Randy Williams, PhD

Problematic use of alcohol is a major source of morbidity¹ and mortality.² It is also common: 7.4% of adults in the United States meet criteria for a past-year alcohol use disorder,³ and 15.8% have had at least one episode of heavy drinking in the past month.⁴ In randomized clinical trials, brief interventions in primary care settings have helped 20% of hazardous and harmful drinkers reduce alcohol consumption to safe levels.^5,6

In medical practice, however, most individuals who engage in hazardous or harmful drinking go undetected,⁷ despite the availability of effective screening instruments.⁸ Major barriers to implementing screening for alcohol problems include a lack of physician familiarity with screening methods^7,9 and a lack of time.¹⁰ A simple time-efficient instrument could increase the frequency of screening, which could reduce the burden of alcohol-related harm in our society.

Previous research in primary care showed that a single question about the last occasion of heavy drinking had a sensitivity of 62% and a specificity of 93% for detecting patients with either a past-year alcohol use disorder or hazardous drinking in the past month.¹¹ In that study, the question was presented in written form: “On any single occasion during the past 3 months, have you had more than 5 drinks containing alcohol?” In this report, we examine the clinical utility of a revision of that question presented orally with different threshold values for men and women as a screening instrument for problem drinking among injured patients presenting to emergency departments.

Methods

Data for this report were taken from a study of alcohol and injury that was approved by the institutional review board of the University Health Science Center. Interviews were conducted with patients presenting for care to 1 of the 3 hospital emergency departments in Boone County, Missouri, within 48 hours of an acute injury. Patients were eligible for the study if they were aged 18 years or older, able to converse in English, cognitively intact, not in police custody, and if the injury did not occur in a controlled environment (eg, a nursing home or jail where access to alcohol is limited). Research staff trained in the use of the structured interview provided equal coverage of each day of the week and hour of the day. Interviews were conducted from February 1998 through March 2000.

Instruments

After obtaining informed consent, the first question of the structured interview was about tobacco use. The second was, “When was the last time you had more than X drinks in 1 day?” with X = 5 for men and X=4 for women. The answers were coded as never, more than 12 months ago, 3 to 12 months ago, and within the last 3 months. The threshold values were based on empirical work¹² and guidelines;¹³ we set them one drink higher than in the guidelines to balance sensitivity and specificity based on our previous work.¹¹

We defined problem drinking as either past-month hazardous drinking or a past-year alcohol use disorder. We defined hazardous drinking as consumption of more than 4 drinks in 1 day or 14 in 1 week for men, more than 3 in 1 day or 7 in 1 week for women. One drink in the United States contains approximately 11.5 g of ethanol, the amount in 12 oz of beer, 5 oz of wine, or 1.5 oz of liquor. Data for this assessment were from a 29-day retrospective calendar-based review of day-by-day consumption.¹⁴ We defined alcohol use disorders (ie, alcohol abuse or dependence) according to the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV),¹⁵ using the alcohol questions in the structured Diagnostic Interview Schedule (DIS).¹⁶ Participants were given a breath alcohol test at the end of the interview using the Alco-Sensor IV model breathalyzer (Intoximeters, Inc, St. Louis, Mo).

Patients

Of 3616 injured persons presenting for care to one of the participating emergency centers during times when research staff were present, 579 were excluded, because the injury occurred more than 48 hours before, because of mental status changes (chronic or acute), or because the injury occurred in a controlled environment. Of 3037 eligible patients on covered shifts, 12.2% declined to participate, and 15.4% were missed, either because their injuries were severe enough to preclude an interview in the emergency department (8.1%) or because research staff were busy with other interviews (7.3%); 2199 persons were interviewed during covered emergency department shifts from February 1998 through January 2000.

Some injured patients were missed because of the severity of their injuries. Therefore, we recruited additional patients who had been admitted to the hospital during times not covered in the emergency department by study staff. These interviews were conducted from June 1999 through March 2000. A total of 618 were identified: 52 refused (8.4%); 69 were too severely injured (11.2%); and 139 were missed (22.5%), leaving 358 who were interviewed.

We combined these 2 groups (from covered and noncovered emergency department shifts) and excluded those from noncovered shifts who had minimal effect on the results presented here. Of those 2557 interviews, 40 were with patients who had been injured and interviewed before. We excluded these from analysis, leaving 2517 individual patients. Table 1 shows basic demographic data and prevalence of alcohol problems. Seven patients (0.3% of interviews) did not answer the single problem-drinking screening question, and 13 (0.5%) did not complete the calendar-based review of recent drinking.

Statistical Analysis

We used bivariate analysis to calculate sensitivity and specificity, and confidence interval (CI) analysis¹⁷ to determine 95% CIs. We used the c statistic from logistic regression to calculate the area under the receiver-operating characteristic (ROC) curve¹⁸ in bivariate and multivariate models. We used the formula in Hanley and McNeil1⁹ to calculate 95% CIs around the area under the ROC curve.*

Results

For detecting problem drinking, the single question (with “within the last 3 months” considered positive) had a sensitivity of 86% and a specificity of 86% Table 2. Sensitivity was higher in men; specificity was higher in women. The question was better in detecting hazardous drinking than alcohol use disorder and more effective in whites than in African Americans. In this study with a prevalence of problem drinking of 35%, the positive and negative predictive values were 77% and 92%. In a clinical setting with a prevalence of 15% (the national prevalence of past-month heavy drinking⁴), positive and negative predictive values would be 52% and 97%. Likelihood ratios18 are provided in Table 3.

Breath or blood alcohol levels were obtained for 2335 patients; 257 had some alcohol detected, and 139 had a level of 0.22 mmol/L (0.1 g/dL) or greater. Of 1493 patients without hazardous drinking or an alcohol use disorder only 49 had any alcohol detected, a specificity of 96%. However, the sensitivity of alcohol testing was only 24% (198 with a positive breath or blood alcohol level out of 842 with problem drinking). Interestingly, 27 of the patients with an alcohol level higher than 0.22 mmol/L (indicative of problem drinking) were negative by the criterion standards (22 of the 27 screened positive with the single question).

Tobacco use is common among patients with alcohol use disorders²⁰ and was associated with problem drinking in our study. Almost half the patients in this study used tobacco in some form; 1013 were cigarette smokers, and 139 used only other forms of tobacco. Current tobacco use had a sensitivity 65% and a specificity of 64% in identifying problem drinking.

The single screening question had 4 answer options (never, >12 months ago, 3-12 months, and within the last 3 months). Using the 3 cut points defined by those answer options, the area under the ROC curve²¹ for identifying problem drinking was 0.90 (95% CI, 0.88-0.91). With a past-year alcohol use disorder as the diagnostic criterion, the area under the ROC curve was 0.81 (95% CI, 0.79-0.83). Entering the single question, sex, age (continuous or ordinal), and tobacco use as independent variables, the area under the ROC curve increased minimally to 0.91 Figure 1. Entering race/ethnicity, injury severity score,²² or alcohol level into the model had essentially no effect. Considering only current drinkers (n=1535), the single question had a sensitivity for detecting problem drinking of 86% and a specificity of 69%, and the area under the ROC curve was 0.79 (95% CI, 0.77-0.82).

Discussion

A single question about recent heavy drinking has clinically useful sensitivity and specificity for detecting recent hazardous drinking and current alcohol use disorders. In response to “When was the last time you had more than X drinks in one day?”, an answer within the past 3 months has a sensitivity and a specificity of 86%. An answer of “never” with a sensitivity of more than 99% essentially rules out problem drinking. The question has less utility in African American patients, but works equally well in women and men.

Previous studies have explored the utility of a single question about the frequency of drinking 5 or more drinks at one time. Drinking 5 or more drinks on one occasion at least once in the past year had a sensitivity of 86% and a specificity of 63% in detecting past-year alcohol dependence.²³ In an emergency center–based study with a positive screening result defined as heavy drinking at least monthly, sensitivity was 58% and specificity 85%.²⁴ The authors of these reports concluded that a single question about the frequency of heavy drinking was inadequate in screening for problem drinking. However, the question we used inquired about the last occasion of heavy drinking not the usual frequency and used different thresholds for men and women, narrowing the sex differences in sensitivity and specificity found in previous work using a single threshold.¹¹

The single question we used compares favorably with the CAGE²⁵ and the Alcohol Use Disorders Identification Test (AUDIT).²⁶ For the single question, the area under the ROC curve is 0.90 for problem drinking and 0.81 for alcohol use disorders only. With the AUDIT,²⁷ the area under the ROC curve was 0.83 to 0.90 in a variety of settings in detecting alcohol use disorders^26,28,29 (hazardous drinkers not included) and 0.88 in detecting problem drinking.²⁹ With the CAGE questions the area under the ROC curve was 0.89 in one study²⁵ and 0.68 to 0.88 in a variety of sex-ethnic subgroups in another²⁶ for detecting alcohol use disorders only.

The criterion standards we used are reliable and valid.^14,30 Although they were negative in 27 patients with alcohol levels of 0.22 mmol/L or greater in whom intoxication may have limited the validity of self-report, 22 of those 27 patients had a positive screening result with the single question.

Limitations

Several limitations of our study should be noted. The interviewer was aware of the patient’s response on the screening question, and this may have led to ascertainment bias. However, the interview was the same for all participants whether their screen produced positive or negative results, and the DIS is a fully structured interview, minimizing this potential bias.

The study is limited by its nonparticipation rate of 30%. Of eligible injured patients from covered emergency department shifts 15.4% were missed, either because interviewers were busy with other participants or because the patient had severe injuries that precluded interview. Another 12.2% declined to participate. The utility of the screening question in these patients is unknown.

The single question did not perform as well for African Americans as it did for whites; its sensitivity and specificity, however, are clinically useful in both groups. Consistent with the population of central Missouri, the study included few members of other ethnic groups, and the question’s utility in those groups needs study.

The generalizability of our findings may be limited. The study included only injured patients presenting for care to emergency centers in central Missouri. However, alcohol-related injury is a major source of morbidity and mortality especially among young adults, and brief interventions in emergency centers are efficacious.³¹ We have little reason to expect the question used in this study would be less effective in other clinical settings.

We examined only one approach to screening. However, the screening question used in this study was selected in advance and remained unchanged throughout data collection. Some screening instruments³² developed post hoc from a longer list of questions have been validated in separate samples,²⁴ but others^33,34 have not.^35,36

Given the morbidity associated with hazardous drinking and the efficacy of brief interventions, screening should include hazardous drinking as well as alcohol use disorders, which we did in this study. Studies of other screening instruments have generally tested their utility only in detecting alcohol use disorders, in which the single question was less specific. Although our study did not address the issue, the single question probably would not identify patients in long-term recovery from a past alcohol use disorder, especially those abstinent for more than a year.

Conclusions

Further study is needed to determine whether clinicians will find this single question easier to apply and whether problem drinkers find it more engaging than alternative screening instruments. The goal of screening is to identify problem drinkers and to engage them effectively in the process of change.³⁷ Different screening approaches—and different ways of following up positive screen results—may vary in their ability to help problem drinkers move toward change.

A single question about the last occasion of heavy drinking has clinically useful sensitivity and specificity in detecting hazardous drinkers and current alcohol use disorders. The question is simple enough that it could be used, as is a question about tobacco use,³⁸ as part of the taking of routine vital signs. If the question used in our study were adopted, it could efficiently identify which patients require further discussion about their drinking habits, with positive and negative predictive values of 77% and 92% in this emergency center population, approximately 52% and 97%, respectively, in a typical population-based sample. That in turn could lead to more frequent use of effective brief intervention and referral strategies, thereby potentially decreasing society’s burden of alcohol-related harm.

Acknowledgments

Our study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism (R01 AA11078). During pilot work, Dr Vinson was supported by a Generalist Physician Faculty Scholars Program grant from the Robert Wood Johnson Foundation. The work has also been supported in part by a research center grant from the American Academy of Family Physicians and by the Opal Lewis Fund for Alcohol Research. Data were collected by Deborah Bailey; Ciprian Crismaru, MD; Amelia Devera-Sales, MD; Kari Gilmore; Indira Gujral; Carol Reidinger; and Carey Smith. Data collection was assisted by the following medical students: Stephen Griffith, Darin Lee, Greg Morlin, Rebecca Shumate, Lindsey Thornton, and Aneesh Tosh. Data management was provided by Darla Horman, MA; Robin Kruse, PhD.; and Sandra Taylor. Logistic regression analyses were performed by Jim Hewett, MS; John Hewett, PhD; and Fan Liu. We also thank the personnel of the emergency centers of the University of Missouri, Boone Hospital Center, and Columbia Regional Hospital.

Related resources

FOR PATIENTS:

• “How to Cut Down on Your Drinking,” a brochure for patients from the National Institute on Alcohol Abuse and Alcoholism (NIAAA)http://www.niaaa.nih.gov/publications/handout.htm
• The Center for Substance Abuse Treatment—includes searchable database of substance abuse treatment programs with maps, phone numbers, types of insurance coverage accepted by each center, and other information. Part of the federal Substance Abuse and Mental Health Services Administration.http://www.samhsa.gov/centers/csat/csat.html
• Alcoholics Anonymous http://www.aa.org
• Moderation Management (seeks to help problem drinkers control their consumption)http://www.moderation.org
• Join Together, an advocacy group addressing alcohol and other drug abuse, violence, etc. Resources for individuals, parents, other groups. http://www.jointogether.org/sa/

FOR FAMILY PHYSICIANS/RESEARCHERS:

• “The Physicians’Guide to Helping Patients with Alcohol Problems,” also published by NIAAA.http://www.niaaa.nih.gov/publications/physicn.htm
• The Research Society on Alcoholism http://www.rsa.am/
• Association for Medical Education and Research in Substance Abusehttp://www.amersa.org/
• American Society of Addiction Medicinehttp://www.asam.org/

Problematic use of alcohol is a major source of morbidity¹ and mortality.² It is also common: 7.4% of adults in the United States meet criteria for a past-year alcohol use disorder,³ and 15.8% have had at least one episode of heavy drinking in the past month.⁴ In randomized clinical trials, brief interventions in primary care settings have helped 20% of hazardous and harmful drinkers reduce alcohol consumption to safe levels.^5,6

In medical practice, however, most individuals who engage in hazardous or harmful drinking go undetected,⁷ despite the availability of effective screening instruments.⁸ Major barriers to implementing screening for alcohol problems include a lack of physician familiarity with screening methods^7,9 and a lack of time.¹⁰ A simple time-efficient instrument could increase the frequency of screening, which could reduce the burden of alcohol-related harm in our society.

Previous research in primary care showed that a single question about the last occasion of heavy drinking had a sensitivity of 62% and a specificity of 93% for detecting patients with either a past-year alcohol use disorder or hazardous drinking in the past month.¹¹ In that study, the question was presented in written form: “On any single occasion during the past 3 months, have you had more than 5 drinks containing alcohol?” In this report, we examine the clinical utility of a revision of that question presented orally with different threshold values for men and women as a screening instrument for problem drinking among injured patients presenting to emergency departments.

Methods

Data for this report were taken from a study of alcohol and injury that was approved by the institutional review board of the University Health Science Center. Interviews were conducted with patients presenting for care to 1 of the 3 hospital emergency departments in Boone County, Missouri, within 48 hours of an acute injury. Patients were eligible for the study if they were aged 18 years or older, able to converse in English, cognitively intact, not in police custody, and if the injury did not occur in a controlled environment (eg, a nursing home or jail where access to alcohol is limited). Research staff trained in the use of the structured interview provided equal coverage of each day of the week and hour of the day. Interviews were conducted from February 1998 through March 2000.

Instruments

After obtaining informed consent, the first question of the structured interview was about tobacco use. The second was, “When was the last time you had more than X drinks in 1 day?” with X = 5 for men and X=4 for women. The answers were coded as never, more than 12 months ago, 3 to 12 months ago, and within the last 3 months. The threshold values were based on empirical work¹² and guidelines;¹³ we set them one drink higher than in the guidelines to balance sensitivity and specificity based on our previous work.¹¹

We defined problem drinking as either past-month hazardous drinking or a past-year alcohol use disorder. We defined hazardous drinking as consumption of more than 4 drinks in 1 day or 14 in 1 week for men, more than 3 in 1 day or 7 in 1 week for women. One drink in the United States contains approximately 11.5 g of ethanol, the amount in 12 oz of beer, 5 oz of wine, or 1.5 oz of liquor. Data for this assessment were from a 29-day retrospective calendar-based review of day-by-day consumption.¹⁴ We defined alcohol use disorders (ie, alcohol abuse or dependence) according to the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV),¹⁵ using the alcohol questions in the structured Diagnostic Interview Schedule (DIS).¹⁶ Participants were given a breath alcohol test at the end of the interview using the Alco-Sensor IV model breathalyzer (Intoximeters, Inc, St. Louis, Mo).

Patients

Of 3616 injured persons presenting for care to one of the participating emergency centers during times when research staff were present, 579 were excluded, because the injury occurred more than 48 hours before, because of mental status changes (chronic or acute), or because the injury occurred in a controlled environment. Of 3037 eligible patients on covered shifts, 12.2% declined to participate, and 15.4% were missed, either because their injuries were severe enough to preclude an interview in the emergency department (8.1%) or because research staff were busy with other interviews (7.3%); 2199 persons were interviewed during covered emergency department shifts from February 1998 through January 2000.

Some injured patients were missed because of the severity of their injuries. Therefore, we recruited additional patients who had been admitted to the hospital during times not covered in the emergency department by study staff. These interviews were conducted from June 1999 through March 2000. A total of 618 were identified: 52 refused (8.4%); 69 were too severely injured (11.2%); and 139 were missed (22.5%), leaving 358 who were interviewed.

We combined these 2 groups (from covered and noncovered emergency department shifts) and excluded those from noncovered shifts who had minimal effect on the results presented here. Of those 2557 interviews, 40 were with patients who had been injured and interviewed before. We excluded these from analysis, leaving 2517 individual patients. Table 1 shows basic demographic data and prevalence of alcohol problems. Seven patients (0.3% of interviews) did not answer the single problem-drinking screening question, and 13 (0.5%) did not complete the calendar-based review of recent drinking.

Statistical Analysis

We used bivariate analysis to calculate sensitivity and specificity, and confidence interval (CI) analysis¹⁷ to determine 95% CIs. We used the c statistic from logistic regression to calculate the area under the receiver-operating characteristic (ROC) curve¹⁸ in bivariate and multivariate models. We used the formula in Hanley and McNeil1⁹ to calculate 95% CIs around the area under the ROC curve.*

Results

For detecting problem drinking, the single question (with “within the last 3 months” considered positive) had a sensitivity of 86% and a specificity of 86% Table 2. Sensitivity was higher in men; specificity was higher in women. The question was better in detecting hazardous drinking than alcohol use disorder and more effective in whites than in African Americans. In this study with a prevalence of problem drinking of 35%, the positive and negative predictive values were 77% and 92%. In a clinical setting with a prevalence of 15% (the national prevalence of past-month heavy drinking⁴), positive and negative predictive values would be 52% and 97%. Likelihood ratios18 are provided in Table 3.

Breath or blood alcohol levels were obtained for 2335 patients; 257 had some alcohol detected, and 139 had a level of 0.22 mmol/L (0.1 g/dL) or greater. Of 1493 patients without hazardous drinking or an alcohol use disorder only 49 had any alcohol detected, a specificity of 96%. However, the sensitivity of alcohol testing was only 24% (198 with a positive breath or blood alcohol level out of 842 with problem drinking). Interestingly, 27 of the patients with an alcohol level higher than 0.22 mmol/L (indicative of problem drinking) were negative by the criterion standards (22 of the 27 screened positive with the single question).

Tobacco use is common among patients with alcohol use disorders²⁰ and was associated with problem drinking in our study. Almost half the patients in this study used tobacco in some form; 1013 were cigarette smokers, and 139 used only other forms of tobacco. Current tobacco use had a sensitivity 65% and a specificity of 64% in identifying problem drinking.

The single screening question had 4 answer options (never, >12 months ago, 3-12 months, and within the last 3 months). Using the 3 cut points defined by those answer options, the area under the ROC curve²¹ for identifying problem drinking was 0.90 (95% CI, 0.88-0.91). With a past-year alcohol use disorder as the diagnostic criterion, the area under the ROC curve was 0.81 (95% CI, 0.79-0.83). Entering the single question, sex, age (continuous or ordinal), and tobacco use as independent variables, the area under the ROC curve increased minimally to 0.91 Figure 1. Entering race/ethnicity, injury severity score,²² or alcohol level into the model had essentially no effect. Considering only current drinkers (n=1535), the single question had a sensitivity for detecting problem drinking of 86% and a specificity of 69%, and the area under the ROC curve was 0.79 (95% CI, 0.77-0.82).

Discussion

A single question about recent heavy drinking has clinically useful sensitivity and specificity for detecting recent hazardous drinking and current alcohol use disorders. In response to “When was the last time you had more than X drinks in one day?”, an answer within the past 3 months has a sensitivity and a specificity of 86%. An answer of “never” with a sensitivity of more than 99% essentially rules out problem drinking. The question has less utility in African American patients, but works equally well in women and men.

Previous studies have explored the utility of a single question about the frequency of drinking 5 or more drinks at one time. Drinking 5 or more drinks on one occasion at least once in the past year had a sensitivity of 86% and a specificity of 63% in detecting past-year alcohol dependence.²³ In an emergency center–based study with a positive screening result defined as heavy drinking at least monthly, sensitivity was 58% and specificity 85%.²⁴ The authors of these reports concluded that a single question about the frequency of heavy drinking was inadequate in screening for problem drinking. However, the question we used inquired about the last occasion of heavy drinking not the usual frequency and used different thresholds for men and women, narrowing the sex differences in sensitivity and specificity found in previous work using a single threshold.¹¹

The single question we used compares favorably with the CAGE²⁵ and the Alcohol Use Disorders Identification Test (AUDIT).²⁶ For the single question, the area under the ROC curve is 0.90 for problem drinking and 0.81 for alcohol use disorders only. With the AUDIT,²⁷ the area under the ROC curve was 0.83 to 0.90 in a variety of settings in detecting alcohol use disorders^26,28,29 (hazardous drinkers not included) and 0.88 in detecting problem drinking.²⁹ With the CAGE questions the area under the ROC curve was 0.89 in one study²⁵ and 0.68 to 0.88 in a variety of sex-ethnic subgroups in another²⁶ for detecting alcohol use disorders only.

The criterion standards we used are reliable and valid.^14,30 Although they were negative in 27 patients with alcohol levels of 0.22 mmol/L or greater in whom intoxication may have limited the validity of self-report, 22 of those 27 patients had a positive screening result with the single question.

Limitations

Several limitations of our study should be noted. The interviewer was aware of the patient’s response on the screening question, and this may have led to ascertainment bias. However, the interview was the same for all participants whether their screen produced positive or negative results, and the DIS is a fully structured interview, minimizing this potential bias.

The study is limited by its nonparticipation rate of 30%. Of eligible injured patients from covered emergency department shifts 15.4% were missed, either because interviewers were busy with other participants or because the patient had severe injuries that precluded interview. Another 12.2% declined to participate. The utility of the screening question in these patients is unknown.

The single question did not perform as well for African Americans as it did for whites; its sensitivity and specificity, however, are clinically useful in both groups. Consistent with the population of central Missouri, the study included few members of other ethnic groups, and the question’s utility in those groups needs study.

The generalizability of our findings may be limited. The study included only injured patients presenting for care to emergency centers in central Missouri. However, alcohol-related injury is a major source of morbidity and mortality especially among young adults, and brief interventions in emergency centers are efficacious.³¹ We have little reason to expect the question used in this study would be less effective in other clinical settings.

We examined only one approach to screening. However, the screening question used in this study was selected in advance and remained unchanged throughout data collection. Some screening instruments³² developed post hoc from a longer list of questions have been validated in separate samples,²⁴ but others^33,34 have not.^35,36

Given the morbidity associated with hazardous drinking and the efficacy of brief interventions, screening should include hazardous drinking as well as alcohol use disorders, which we did in this study. Studies of other screening instruments have generally tested their utility only in detecting alcohol use disorders, in which the single question was less specific. Although our study did not address the issue, the single question probably would not identify patients in long-term recovery from a past alcohol use disorder, especially those abstinent for more than a year.

Conclusions

Further study is needed to determine whether clinicians will find this single question easier to apply and whether problem drinkers find it more engaging than alternative screening instruments. The goal of screening is to identify problem drinkers and to engage them effectively in the process of change.³⁷ Different screening approaches—and different ways of following up positive screen results—may vary in their ability to help problem drinkers move toward change.

A single question about the last occasion of heavy drinking has clinically useful sensitivity and specificity in detecting hazardous drinkers and current alcohol use disorders. The question is simple enough that it could be used, as is a question about tobacco use,³⁸ as part of the taking of routine vital signs. If the question used in our study were adopted, it could efficiently identify which patients require further discussion about their drinking habits, with positive and negative predictive values of 77% and 92% in this emergency center population, approximately 52% and 97%, respectively, in a typical population-based sample. That in turn could lead to more frequent use of effective brief intervention and referral strategies, thereby potentially decreasing society’s burden of alcohol-related harm.

Acknowledgments

Our study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism (R01 AA11078). During pilot work, Dr Vinson was supported by a Generalist Physician Faculty Scholars Program grant from the Robert Wood Johnson Foundation. The work has also been supported in part by a research center grant from the American Academy of Family Physicians and by the Opal Lewis Fund for Alcohol Research. Data were collected by Deborah Bailey; Ciprian Crismaru, MD; Amelia Devera-Sales, MD; Kari Gilmore; Indira Gujral; Carol Reidinger; and Carey Smith. Data collection was assisted by the following medical students: Stephen Griffith, Darin Lee, Greg Morlin, Rebecca Shumate, Lindsey Thornton, and Aneesh Tosh. Data management was provided by Darla Horman, MA; Robin Kruse, PhD.; and Sandra Taylor. Logistic regression analyses were performed by Jim Hewett, MS; John Hewett, PhD; and Fan Liu. We also thank the personnel of the emergency centers of the University of Missouri, Boone Hospital Center, and Columbia Regional Hospital.

Related resources

FOR PATIENTS:

• “How to Cut Down on Your Drinking,” a brochure for patients from the National Institute on Alcohol Abuse and Alcoholism (NIAAA)http://www.niaaa.nih.gov/publications/handout.htm
• The Center for Substance Abuse Treatment—includes searchable database of substance abuse treatment programs with maps, phone numbers, types of insurance coverage accepted by each center, and other information. Part of the federal Substance Abuse and Mental Health Services Administration.http://www.samhsa.gov/centers/csat/csat.html
• Alcoholics Anonymous http://www.aa.org
• Moderation Management (seeks to help problem drinkers control their consumption)http://www.moderation.org
• Join Together, an advocacy group addressing alcohol and other drug abuse, violence, etc. Resources for individuals, parents, other groups. http://www.jointogether.org/sa/

FOR FAMILY PHYSICIANS/RESEARCHERS:

• “The Physicians’Guide to Helping Patients with Alcohol Problems,” also published by NIAAA.http://www.niaaa.nih.gov/publications/physicn.htm
• The Research Society on Alcoholism http://www.rsa.am/
• Association for Medical Education and Research in Substance Abusehttp://www.amersa.org/
• American Society of Addiction Medicinehttp://www.asam.org/

Problematic use of alcohol is a major source of morbidity¹ and mortality.² It is also common: 7.4% of adults in the United States meet criteria for a past-year alcohol use disorder,³ and 15.8% have had at least one episode of heavy drinking in the past month.⁴ In randomized clinical trials, brief interventions in primary care settings have helped 20% of hazardous and harmful drinkers reduce alcohol consumption to safe levels.^5,6

In medical practice, however, most individuals who engage in hazardous or harmful drinking go undetected,⁷ despite the availability of effective screening instruments.⁸ Major barriers to implementing screening for alcohol problems include a lack of physician familiarity with screening methods^7,9 and a lack of time.¹⁰ A simple time-efficient instrument could increase the frequency of screening, which could reduce the burden of alcohol-related harm in our society.

Previous research in primary care showed that a single question about the last occasion of heavy drinking had a sensitivity of 62% and a specificity of 93% for detecting patients with either a past-year alcohol use disorder or hazardous drinking in the past month.¹¹ In that study, the question was presented in written form: “On any single occasion during the past 3 months, have you had more than 5 drinks containing alcohol?” In this report, we examine the clinical utility of a revision of that question presented orally with different threshold values for men and women as a screening instrument for problem drinking among injured patients presenting to emergency departments.

Methods

Data for this report were taken from a study of alcohol and injury that was approved by the institutional review board of the University Health Science Center. Interviews were conducted with patients presenting for care to 1 of the 3 hospital emergency departments in Boone County, Missouri, within 48 hours of an acute injury. Patients were eligible for the study if they were aged 18 years or older, able to converse in English, cognitively intact, not in police custody, and if the injury did not occur in a controlled environment (eg, a nursing home or jail where access to alcohol is limited). Research staff trained in the use of the structured interview provided equal coverage of each day of the week and hour of the day. Interviews were conducted from February 1998 through March 2000.

Instruments

After obtaining informed consent, the first question of the structured interview was about tobacco use. The second was, “When was the last time you had more than X drinks in 1 day?” with X = 5 for men and X=4 for women. The answers were coded as never, more than 12 months ago, 3 to 12 months ago, and within the last 3 months. The threshold values were based on empirical work¹² and guidelines;¹³ we set them one drink higher than in the guidelines to balance sensitivity and specificity based on our previous work.¹¹

We defined problem drinking as either past-month hazardous drinking or a past-year alcohol use disorder. We defined hazardous drinking as consumption of more than 4 drinks in 1 day or 14 in 1 week for men, more than 3 in 1 day or 7 in 1 week for women. One drink in the United States contains approximately 11.5 g of ethanol, the amount in 12 oz of beer, 5 oz of wine, or 1.5 oz of liquor. Data for this assessment were from a 29-day retrospective calendar-based review of day-by-day consumption.¹⁴ We defined alcohol use disorders (ie, alcohol abuse or dependence) according to the criteria in the Diagnostic and Statistical Manual of Mental Disorders, 4th edition (DSM-IV),¹⁵ using the alcohol questions in the structured Diagnostic Interview Schedule (DIS).¹⁶ Participants were given a breath alcohol test at the end of the interview using the Alco-Sensor IV model breathalyzer (Intoximeters, Inc, St. Louis, Mo).

Patients

Of 3616 injured persons presenting for care to one of the participating emergency centers during times when research staff were present, 579 were excluded, because the injury occurred more than 48 hours before, because of mental status changes (chronic or acute), or because the injury occurred in a controlled environment. Of 3037 eligible patients on covered shifts, 12.2% declined to participate, and 15.4% were missed, either because their injuries were severe enough to preclude an interview in the emergency department (8.1%) or because research staff were busy with other interviews (7.3%); 2199 persons were interviewed during covered emergency department shifts from February 1998 through January 2000.

Some injured patients were missed because of the severity of their injuries. Therefore, we recruited additional patients who had been admitted to the hospital during times not covered in the emergency department by study staff. These interviews were conducted from June 1999 through March 2000. A total of 618 were identified: 52 refused (8.4%); 69 were too severely injured (11.2%); and 139 were missed (22.5%), leaving 358 who were interviewed.

We combined these 2 groups (from covered and noncovered emergency department shifts) and excluded those from noncovered shifts who had minimal effect on the results presented here. Of those 2557 interviews, 40 were with patients who had been injured and interviewed before. We excluded these from analysis, leaving 2517 individual patients. Table 1 shows basic demographic data and prevalence of alcohol problems. Seven patients (0.3% of interviews) did not answer the single problem-drinking screening question, and 13 (0.5%) did not complete the calendar-based review of recent drinking.

Statistical Analysis

We used bivariate analysis to calculate sensitivity and specificity, and confidence interval (CI) analysis¹⁷ to determine 95% CIs. We used the c statistic from logistic regression to calculate the area under the receiver-operating characteristic (ROC) curve¹⁸ in bivariate and multivariate models. We used the formula in Hanley and McNeil1⁹ to calculate 95% CIs around the area under the ROC curve.*

Results

For detecting problem drinking, the single question (with “within the last 3 months” considered positive) had a sensitivity of 86% and a specificity of 86% Table 2. Sensitivity was higher in men; specificity was higher in women. The question was better in detecting hazardous drinking than alcohol use disorder and more effective in whites than in African Americans. In this study with a prevalence of problem drinking of 35%, the positive and negative predictive values were 77% and 92%. In a clinical setting with a prevalence of 15% (the national prevalence of past-month heavy drinking⁴), positive and negative predictive values would be 52% and 97%. Likelihood ratios18 are provided in Table 3.

Breath or blood alcohol levels were obtained for 2335 patients; 257 had some alcohol detected, and 139 had a level of 0.22 mmol/L (0.1 g/dL) or greater. Of 1493 patients without hazardous drinking or an alcohol use disorder only 49 had any alcohol detected, a specificity of 96%. However, the sensitivity of alcohol testing was only 24% (198 with a positive breath or blood alcohol level out of 842 with problem drinking). Interestingly, 27 of the patients with an alcohol level higher than 0.22 mmol/L (indicative of problem drinking) were negative by the criterion standards (22 of the 27 screened positive with the single question).

Tobacco use is common among patients with alcohol use disorders²⁰ and was associated with problem drinking in our study. Almost half the patients in this study used tobacco in some form; 1013 were cigarette smokers, and 139 used only other forms of tobacco. Current tobacco use had a sensitivity 65% and a specificity of 64% in identifying problem drinking.

The single screening question had 4 answer options (never, >12 months ago, 3-12 months, and within the last 3 months). Using the 3 cut points defined by those answer options, the area under the ROC curve²¹ for identifying problem drinking was 0.90 (95% CI, 0.88-0.91). With a past-year alcohol use disorder as the diagnostic criterion, the area under the ROC curve was 0.81 (95% CI, 0.79-0.83). Entering the single question, sex, age (continuous or ordinal), and tobacco use as independent variables, the area under the ROC curve increased minimally to 0.91 Figure 1. Entering race/ethnicity, injury severity score,²² or alcohol level into the model had essentially no effect. Considering only current drinkers (n=1535), the single question had a sensitivity for detecting problem drinking of 86% and a specificity of 69%, and the area under the ROC curve was 0.79 (95% CI, 0.77-0.82).

Discussion

A single question about recent heavy drinking has clinically useful sensitivity and specificity for detecting recent hazardous drinking and current alcohol use disorders. In response to “When was the last time you had more than X drinks in one day?”, an answer within the past 3 months has a sensitivity and a specificity of 86%. An answer of “never” with a sensitivity of more than 99% essentially rules out problem drinking. The question has less utility in African American patients, but works equally well in women and men.

Previous studies have explored the utility of a single question about the frequency of drinking 5 or more drinks at one time. Drinking 5 or more drinks on one occasion at least once in the past year had a sensitivity of 86% and a specificity of 63% in detecting past-year alcohol dependence.²³ In an emergency center–based study with a positive screening result defined as heavy drinking at least monthly, sensitivity was 58% and specificity 85%.²⁴ The authors of these reports concluded that a single question about the frequency of heavy drinking was inadequate in screening for problem drinking. However, the question we used inquired about the last occasion of heavy drinking not the usual frequency and used different thresholds for men and women, narrowing the sex differences in sensitivity and specificity found in previous work using a single threshold.¹¹

The single question we used compares favorably with the CAGE²⁵ and the Alcohol Use Disorders Identification Test (AUDIT).²⁶ For the single question, the area under the ROC curve is 0.90 for problem drinking and 0.81 for alcohol use disorders only. With the AUDIT,²⁷ the area under the ROC curve was 0.83 to 0.90 in a variety of settings in detecting alcohol use disorders^26,28,29 (hazardous drinkers not included) and 0.88 in detecting problem drinking.²⁹ With the CAGE questions the area under the ROC curve was 0.89 in one study²⁵ and 0.68 to 0.88 in a variety of sex-ethnic subgroups in another²⁶ for detecting alcohol use disorders only.

The criterion standards we used are reliable and valid.^14,30 Although they were negative in 27 patients with alcohol levels of 0.22 mmol/L or greater in whom intoxication may have limited the validity of self-report, 22 of those 27 patients had a positive screening result with the single question.

Limitations

Several limitations of our study should be noted. The interviewer was aware of the patient’s response on the screening question, and this may have led to ascertainment bias. However, the interview was the same for all participants whether their screen produced positive or negative results, and the DIS is a fully structured interview, minimizing this potential bias.

The study is limited by its nonparticipation rate of 30%. Of eligible injured patients from covered emergency department shifts 15.4% were missed, either because interviewers were busy with other participants or because the patient had severe injuries that precluded interview. Another 12.2% declined to participate. The utility of the screening question in these patients is unknown.

The single question did not perform as well for African Americans as it did for whites; its sensitivity and specificity, however, are clinically useful in both groups. Consistent with the population of central Missouri, the study included few members of other ethnic groups, and the question’s utility in those groups needs study.

The generalizability of our findings may be limited. The study included only injured patients presenting for care to emergency centers in central Missouri. However, alcohol-related injury is a major source of morbidity and mortality especially among young adults, and brief interventions in emergency centers are efficacious.³¹ We have little reason to expect the question used in this study would be less effective in other clinical settings.

We examined only one approach to screening. However, the screening question used in this study was selected in advance and remained unchanged throughout data collection. Some screening instruments³² developed post hoc from a longer list of questions have been validated in separate samples,²⁴ but others^33,34 have not.^35,36

Given the morbidity associated with hazardous drinking and the efficacy of brief interventions, screening should include hazardous drinking as well as alcohol use disorders, which we did in this study. Studies of other screening instruments have generally tested their utility only in detecting alcohol use disorders, in which the single question was less specific. Although our study did not address the issue, the single question probably would not identify patients in long-term recovery from a past alcohol use disorder, especially those abstinent for more than a year.

Conclusions

Further study is needed to determine whether clinicians will find this single question easier to apply and whether problem drinkers find it more engaging than alternative screening instruments. The goal of screening is to identify problem drinkers and to engage them effectively in the process of change.³⁷ Different screening approaches—and different ways of following up positive screen results—may vary in their ability to help problem drinkers move toward change.

A single question about the last occasion of heavy drinking has clinically useful sensitivity and specificity in detecting hazardous drinkers and current alcohol use disorders. The question is simple enough that it could be used, as is a question about tobacco use,³⁸ as part of the taking of routine vital signs. If the question used in our study were adopted, it could efficiently identify which patients require further discussion about their drinking habits, with positive and negative predictive values of 77% and 92% in this emergency center population, approximately 52% and 97%, respectively, in a typical population-based sample. That in turn could lead to more frequent use of effective brief intervention and referral strategies, thereby potentially decreasing society’s burden of alcohol-related harm.

Acknowledgments

Our study was supported by a grant from the National Institute on Alcohol Abuse and Alcoholism (R01 AA11078). During pilot work, Dr Vinson was supported by a Generalist Physician Faculty Scholars Program grant from the Robert Wood Johnson Foundation. The work has also been supported in part by a research center grant from the American Academy of Family Physicians and by the Opal Lewis Fund for Alcohol Research. Data were collected by Deborah Bailey; Ciprian Crismaru, MD; Amelia Devera-Sales, MD; Kari Gilmore; Indira Gujral; Carol Reidinger; and Carey Smith. Data collection was assisted by the following medical students: Stephen Griffith, Darin Lee, Greg Morlin, Rebecca Shumate, Lindsey Thornton, and Aneesh Tosh. Data management was provided by Darla Horman, MA; Robin Kruse, PhD.; and Sandra Taylor. Logistic regression analyses were performed by Jim Hewett, MS; John Hewett, PhD; and Fan Liu. We also thank the personnel of the emergency centers of the University of Missouri, Boone Hospital Center, and Columbia Regional Hospital.

Related resources

FOR PATIENTS:

• “How to Cut Down on Your Drinking,” a brochure for patients from the National Institute on Alcohol Abuse and Alcoholism (NIAAA)http://www.niaaa.nih.gov/publications/handout.htm
• The Center for Substance Abuse Treatment—includes searchable database of substance abuse treatment programs with maps, phone numbers, types of insurance coverage accepted by each center, and other information. Part of the federal Substance Abuse and Mental Health Services Administration.http://www.samhsa.gov/centers/csat/csat.html
• Alcoholics Anonymous http://www.aa.org
• Moderation Management (seeks to help problem drinkers control their consumption)http://www.moderation.org
• Join Together, an advocacy group addressing alcohol and other drug abuse, violence, etc. Resources for individuals, parents, other groups. http://www.jointogether.org/sa/

FOR FAMILY PHYSICIANS/RESEARCHERS:

• “The Physicians’Guide to Helping Patients with Alcohol Problems,” also published by NIAAA.http://www.niaaa.nih.gov/publications/physicn.htm
• The Research Society on Alcoholism http://www.rsa.am/
• Association for Medical Education and Research in Substance Abusehttp://www.amersa.org/
• American Society of Addiction Medicinehttp://www.asam.org/