Nancy Calabretta, MS, MD

Evidence summary

SCD in athletes is a rare event; researchers estimate the annual incidence at 0.5 to 2 per 100,000 athletes per year.^1,2 The rarity of SCD, lack of registries recording cases, multiple causes, and varying demographics limit accurate estimation of its incidence.³ Experts also debate whether the ability of a single EKG to detect a potentially lethal arrhythmia outweighs the expense and potential harm of false-positive results. No randomized controlled trials have assessed the efficacy of preparticipation screening, with or without EKG, to reduce SCD. The major studies evaluating this issue are observational and retrospective.

An Italian study suggests lower SCD mortality with EKG screening
An Italian observational study of 33,735 athletes reported results of a 25-year program of mandated SCD screening (1979-2004).⁴ Researchers found that the incidence of sudden death was 89% lower at the end of the screening program (0.4/100,000 athletes/year), compared with the baseline (3.6/100,000 athletes/year).

The program used highly trained sports medicine physicians and supplemented the history and physical examination with universal EKG screening. Screening began at 12 to 14 years of age and was repeated regularly as long as the athlete was engaging in competition. The incidence of SCD in nonathletes (0.79/100,000 nonathletes/year) didn’t change over the 25 years of the study.

Limitations of the study include the lack of a concurrent control group of unscreened athletes and time-dependent bias, also known as immortal time bias. (Studies with time-dependent outcomes in which the test of interest, such as EKG screening, and the outcome analyzed, such as SCD, occur during the same period are susceptible to immortal time bias. Athletes who may have died suddenly during the prescreening period would never have made it to the first screening, so the group of athletes who made it alive to the first screening already represented a selected lower-risk population whose characteristics contributed to the lower mortality rates in the postscreening period.)

Other study limitations included baseline differences in male-to-female ratio (82% male) and age range (12-35 years). In addition, the study used a short measurement time (approximately 3 years) to establish a baseline SCD incidence, resulting in a higher incidence than the average in other studies.

An Israeli study suggests otherwise
An uncontrolled observational study done in Israel compared the number of SCDs before and after implementation of a mandatory nationwide screening program for all athletes.⁵ The screening protocol included a medical questionnaire, physical examination, resting EKG, and exercise stress test. Researchers estimated the SCD incidence by scrutinizing newspaper reports of sudden deaths in competitive athletes for 2 time periods: 12 years before (1985-1997) and 12 years after (1997-2009) the intervention.

They identified 24 presumed cardiac deaths, all in male athletes 12 to 44 years of age (mean 23.9 years). The incidence of SCD in the athletes before and after this protocol was 2.54 and 2.66/100,000 athletes/year, respectively (P not significant).

An advantage of this study is the longer period used to estimate SCD incidence (12 years compared with approximately 3 years). A disadvantage is that the researchers calculated the SCD incidence by relying only on media reports rather than on a death registry.

A US comparison study supports the Israeli findings
In the United States, researchers compared SCD rates in high school and college athletes in Minnesota with the rates reported in the Italian study discussed previously.¹ They collected mortality data from several sources, including a national death registry, over a similar time period (1985-2007), during which routine EKG screening of Minnesota athletes wasn’t mandated or recommended.

During the 23-year study period, SCD mortality rates in young athletes in Minnesota remained stable at 0.97/100,000 athletes/year (range 0.5-1.3). This rate didn’t differ significantly from the death rate reported at the end of the Italian study.⁴ The US authors concluded that their data didn’t support the hypothesis that routine EKG screening in young athletes results in lower SCD mortality.¹

Recommendations

All major groups acknowledge that EKG screening improves the sensitivity of the preparticipation physical exam. The European Society of Cardiology Study Group of Sport Cardiology and the International Olympic Committee advocate routine screening.^6,7

The American Heart Association (AHA) Council on Nutrition, Physical Activity, and Metabolism and the American College of Sports Medicine don’t recommend routine EKGs as part of the preparticipation evaluation of school-aged athletes.^8,9

The AHA recommends that a qualified examiner perform a full history and physical exam, which includes assessments of 12 key risk factors (TABLE), and advocates cardiovascular referral for patients who show positive findings.

TABLE
12 cardiovascular risk factors to watch for during preparticipation physicals for school-aged athletes

Evidence summary

SCD in athletes is a rare event; researchers estimate the annual incidence at 0.5 to 2 per 100,000 athletes per year.^1,2 The rarity of SCD, lack of registries recording cases, multiple causes, and varying demographics limit accurate estimation of its incidence.³ Experts also debate whether the ability of a single EKG to detect a potentially lethal arrhythmia outweighs the expense and potential harm of false-positive results. No randomized controlled trials have assessed the efficacy of preparticipation screening, with or without EKG, to reduce SCD. The major studies evaluating this issue are observational and retrospective.

An Italian study suggests lower SCD mortality with EKG screening
An Italian observational study of 33,735 athletes reported results of a 25-year program of mandated SCD screening (1979-2004).⁴ Researchers found that the incidence of sudden death was 89% lower at the end of the screening program (0.4/100,000 athletes/year), compared with the baseline (3.6/100,000 athletes/year).

The program used highly trained sports medicine physicians and supplemented the history and physical examination with universal EKG screening. Screening began at 12 to 14 years of age and was repeated regularly as long as the athlete was engaging in competition. The incidence of SCD in nonathletes (0.79/100,000 nonathletes/year) didn’t change over the 25 years of the study.

Limitations of the study include the lack of a concurrent control group of unscreened athletes and time-dependent bias, also known as immortal time bias. (Studies with time-dependent outcomes in which the test of interest, such as EKG screening, and the outcome analyzed, such as SCD, occur during the same period are susceptible to immortal time bias. Athletes who may have died suddenly during the prescreening period would never have made it to the first screening, so the group of athletes who made it alive to the first screening already represented a selected lower-risk population whose characteristics contributed to the lower mortality rates in the postscreening period.)

Other study limitations included baseline differences in male-to-female ratio (82% male) and age range (12-35 years). In addition, the study used a short measurement time (approximately 3 years) to establish a baseline SCD incidence, resulting in a higher incidence than the average in other studies.

An Israeli study suggests otherwise
An uncontrolled observational study done in Israel compared the number of SCDs before and after implementation of a mandatory nationwide screening program for all athletes.⁵ The screening protocol included a medical questionnaire, physical examination, resting EKG, and exercise stress test. Researchers estimated the SCD incidence by scrutinizing newspaper reports of sudden deaths in competitive athletes for 2 time periods: 12 years before (1985-1997) and 12 years after (1997-2009) the intervention.

They identified 24 presumed cardiac deaths, all in male athletes 12 to 44 years of age (mean 23.9 years). The incidence of SCD in the athletes before and after this protocol was 2.54 and 2.66/100,000 athletes/year, respectively (P not significant).

An advantage of this study is the longer period used to estimate SCD incidence (12 years compared with approximately 3 years). A disadvantage is that the researchers calculated the SCD incidence by relying only on media reports rather than on a death registry.

A US comparison study supports the Israeli findings
In the United States, researchers compared SCD rates in high school and college athletes in Minnesota with the rates reported in the Italian study discussed previously.¹ They collected mortality data from several sources, including a national death registry, over a similar time period (1985-2007), during which routine EKG screening of Minnesota athletes wasn’t mandated or recommended.

During the 23-year study period, SCD mortality rates in young athletes in Minnesota remained stable at 0.97/100,000 athletes/year (range 0.5-1.3). This rate didn’t differ significantly from the death rate reported at the end of the Italian study.⁴ The US authors concluded that their data didn’t support the hypothesis that routine EKG screening in young athletes results in lower SCD mortality.¹

Recommendations

All major groups acknowledge that EKG screening improves the sensitivity of the preparticipation physical exam. The European Society of Cardiology Study Group of Sport Cardiology and the International Olympic Committee advocate routine screening.^6,7

The American Heart Association (AHA) Council on Nutrition, Physical Activity, and Metabolism and the American College of Sports Medicine don’t recommend routine EKGs as part of the preparticipation evaluation of school-aged athletes.^8,9

The AHA recommends that a qualified examiner perform a full history and physical exam, which includes assessments of 12 key risk factors (TABLE), and advocates cardiovascular referral for patients who show positive findings.

TABLE
12 cardiovascular risk factors to watch for during preparticipation physicals for school-aged athletes

Evidence summary

SCD in athletes is a rare event; researchers estimate the annual incidence at 0.5 to 2 per 100,000 athletes per year.^1,2 The rarity of SCD, lack of registries recording cases, multiple causes, and varying demographics limit accurate estimation of its incidence.³ Experts also debate whether the ability of a single EKG to detect a potentially lethal arrhythmia outweighs the expense and potential harm of false-positive results. No randomized controlled trials have assessed the efficacy of preparticipation screening, with or without EKG, to reduce SCD. The major studies evaluating this issue are observational and retrospective.

An Italian study suggests lower SCD mortality with EKG screening
An Italian observational study of 33,735 athletes reported results of a 25-year program of mandated SCD screening (1979-2004).⁴ Researchers found that the incidence of sudden death was 89% lower at the end of the screening program (0.4/100,000 athletes/year), compared with the baseline (3.6/100,000 athletes/year).

The program used highly trained sports medicine physicians and supplemented the history and physical examination with universal EKG screening. Screening began at 12 to 14 years of age and was repeated regularly as long as the athlete was engaging in competition. The incidence of SCD in nonathletes (0.79/100,000 nonathletes/year) didn’t change over the 25 years of the study.

Limitations of the study include the lack of a concurrent control group of unscreened athletes and time-dependent bias, also known as immortal time bias. (Studies with time-dependent outcomes in which the test of interest, such as EKG screening, and the outcome analyzed, such as SCD, occur during the same period are susceptible to immortal time bias. Athletes who may have died suddenly during the prescreening period would never have made it to the first screening, so the group of athletes who made it alive to the first screening already represented a selected lower-risk population whose characteristics contributed to the lower mortality rates in the postscreening period.)

Other study limitations included baseline differences in male-to-female ratio (82% male) and age range (12-35 years). In addition, the study used a short measurement time (approximately 3 years) to establish a baseline SCD incidence, resulting in a higher incidence than the average in other studies.

An Israeli study suggests otherwise
An uncontrolled observational study done in Israel compared the number of SCDs before and after implementation of a mandatory nationwide screening program for all athletes.⁵ The screening protocol included a medical questionnaire, physical examination, resting EKG, and exercise stress test. Researchers estimated the SCD incidence by scrutinizing newspaper reports of sudden deaths in competitive athletes for 2 time periods: 12 years before (1985-1997) and 12 years after (1997-2009) the intervention.

They identified 24 presumed cardiac deaths, all in male athletes 12 to 44 years of age (mean 23.9 years). The incidence of SCD in the athletes before and after this protocol was 2.54 and 2.66/100,000 athletes/year, respectively (P not significant).

An advantage of this study is the longer period used to estimate SCD incidence (12 years compared with approximately 3 years). A disadvantage is that the researchers calculated the SCD incidence by relying only on media reports rather than on a death registry.

A US comparison study supports the Israeli findings
In the United States, researchers compared SCD rates in high school and college athletes in Minnesota with the rates reported in the Italian study discussed previously.¹ They collected mortality data from several sources, including a national death registry, over a similar time period (1985-2007), during which routine EKG screening of Minnesota athletes wasn’t mandated or recommended.

During the 23-year study period, SCD mortality rates in young athletes in Minnesota remained stable at 0.97/100,000 athletes/year (range 0.5-1.3). This rate didn’t differ significantly from the death rate reported at the end of the Italian study.⁴ The US authors concluded that their data didn’t support the hypothesis that routine EKG screening in young athletes results in lower SCD mortality.¹

Recommendations

All major groups acknowledge that EKG screening improves the sensitivity of the preparticipation physical exam. The European Society of Cardiology Study Group of Sport Cardiology and the International Olympic Committee advocate routine screening.^6,7

The American Heart Association (AHA) Council on Nutrition, Physical Activity, and Metabolism and the American College of Sports Medicine don’t recommend routine EKGs as part of the preparticipation evaluation of school-aged athletes.^8,9

The AHA recommends that a qualified examiner perform a full history and physical exam, which includes assessments of 12 key risk factors (TABLE), and advocates cardiovascular referral for patients who show positive findings.

TABLE
12 cardiovascular risk factors to watch for during preparticipation physicals for school-aged athletes

Evidence summary

A prospective cohort study¹ evaluated dobutamine or dipyridamole pharmacologic stress echocardiography among 904 primary care patients with either typical or atypical chest pain. Patients were enrolled into the study if they had normal resting wall motion, sinus rhythm, and had no history of coronary artery disease, unstable angina, or PTCA. Patients (average age 61 years, 42% men) were followed for an average of 44 months for primary cardiovascular endpoints (fatal or nonfatal myocardial infarction [MI], unstable angina, PTCA, or cardiac death). A negative or positive stress echocardiography is defined as the absence or presence of abnormal cardiac wall motion on either exercise or pharmacologic stress echocardiography. Eighteen percent of patients had a positive pharmacologic stress echocardiography. Over the length of the study, 81 of 904 patients (9%) suffered a cardiovascular event. Patients with a negative pharmacologic stress echocardiography had a mean annual probability of a cardiovascular event of 0.8% vs 8.5% with a positive pharmacologic stress echocardiography (P<0001). The 4-year infarct-free negative predictive value (NPV) of pharmacologic stress echocardiography was 97%, and the positive predictive value (PPV) was 70%.

A similar prospective cohort study² evaluated 105 patients (50% men) with atypical chest pain in an emergency department setting with either exercise or dobutamine/atropine stress echocardiography. The average patient age was 55 years and follow-up was 2.8 years. Patients were clinically stable, had normal or nondiagnostic electrocardiogram (ECG), normal cardiac enzymes, normal left ventricular function, and no history of coronary artery disease or unstable angina. Cardiovascular endpoints included fatal or nonfatal MI, unstable angina, PTCA, or cardiac death. A total of 7 patients (7%) suffered a cardiovascular event during the follow-up period. Positive stress echocardiography results occurred for 9% of patients. The NPV was 99% and the PPV was 75%.

Three other cohort studies^3-5 evaluated exercise or dobutamine/atropine stress echocardiography for a total of 615 patients (48%–67% men, average age 56–58 years) presenting to an emergency department with classical cardiac or atypical chest pain. Patients had normal or nondiagnostic ECG, negative cardiac enzymes, and either no history of coronary artery disease^3,4 or known coronary artery disease of unknown significance.⁵ A positive stress echocardiography was obtained for 4.8% to 42% of patients in the cohorts. During 6 months of follow-up, cardiovascular events occurred in 4 of 145 patients (3%),³ 22 of 227 patients (6%),⁴ and in 11 of 80 patients (14%).⁵ At 6-month follow-up, exercise stress echocardiography had a NPV of 99.3% and a PPV of 43%.³ Dobutamine/atropine stress echocardiography had a NPV of 95% to 96% and a PPV of 25% to 31%.^4,5

One retrospective review⁶ evaluated exercise and dobutamine/atropine stress echocardiography and stress ECG for 661 low-risk outpatients (48% men, average age 58 years) with atypical chest pain. All patients had normal left ventricular function and no history of coronary artery disease and were followed for an average of 23 months. A positive stress echocardiography test occurred among 16% of the patient population.

During follow-up, 41 of 661 patients (6%) suffered a cardiovascular event. For either exercise or dobutamine/atropine stress echocardiography, the NPV was 99% at 12 months and 96% at 30 months. Patients with a positive stress echocardiography test and a negative stress ECG had a 66% event-free survival rate. Event-free survival rate for patients with a negative stress echocardiography and a positive or negative stress ECG was 97% and 96%, respectively.

Recommendations from others

The American College of Cardiology⁷ gives a Class I recommendation (tests for which there is evidence or general agreement that a given procedure or treatment is useful and effective) for standard echocardiogram for evaluation of chest pain for patients with suspected acute myocardial ischemia (when baseline ECG and other laboratory markers are nondiagnostic and when the study can be obtained during pain or within minutes after its abatement).

It gives a Class IIa recommendation (tests for which there is conflicting evidence or divergence of opinion, but favoring usefulness) to stress echocardiography for the detection of myocardial ischemia for women with an intermediate pretest likelihood of coronary artery disease. It also gives a Class IIa recommendation to stress echocardiography for determining the prognosis of myocardial ischemia among patients for whom ECG assessment is less reliable. This group comprises patients with the following ECG abnormalities: pre-excitation syndrome (such as Wolff-Parkinson-White), electronically paced ventricular rhythm, more than 1 mm of ST depression at rest, and complete left bundle branch block.

Evidence summary

A prospective cohort study¹ evaluated dobutamine or dipyridamole pharmacologic stress echocardiography among 904 primary care patients with either typical or atypical chest pain. Patients were enrolled into the study if they had normal resting wall motion, sinus rhythm, and had no history of coronary artery disease, unstable angina, or PTCA. Patients (average age 61 years, 42% men) were followed for an average of 44 months for primary cardiovascular endpoints (fatal or nonfatal myocardial infarction [MI], unstable angina, PTCA, or cardiac death). A negative or positive stress echocardiography is defined as the absence or presence of abnormal cardiac wall motion on either exercise or pharmacologic stress echocardiography. Eighteen percent of patients had a positive pharmacologic stress echocardiography. Over the length of the study, 81 of 904 patients (9%) suffered a cardiovascular event. Patients with a negative pharmacologic stress echocardiography had a mean annual probability of a cardiovascular event of 0.8% vs 8.5% with a positive pharmacologic stress echocardiography (P<0001). The 4-year infarct-free negative predictive value (NPV) of pharmacologic stress echocardiography was 97%, and the positive predictive value (PPV) was 70%.

A similar prospective cohort study² evaluated 105 patients (50% men) with atypical chest pain in an emergency department setting with either exercise or dobutamine/atropine stress echocardiography. The average patient age was 55 years and follow-up was 2.8 years. Patients were clinically stable, had normal or nondiagnostic electrocardiogram (ECG), normal cardiac enzymes, normal left ventricular function, and no history of coronary artery disease or unstable angina. Cardiovascular endpoints included fatal or nonfatal MI, unstable angina, PTCA, or cardiac death. A total of 7 patients (7%) suffered a cardiovascular event during the follow-up period. Positive stress echocardiography results occurred for 9% of patients. The NPV was 99% and the PPV was 75%.

Three other cohort studies^3-5 evaluated exercise or dobutamine/atropine stress echocardiography for a total of 615 patients (48%–67% men, average age 56–58 years) presenting to an emergency department with classical cardiac or atypical chest pain. Patients had normal or nondiagnostic ECG, negative cardiac enzymes, and either no history of coronary artery disease^3,4 or known coronary artery disease of unknown significance.⁵ A positive stress echocardiography was obtained for 4.8% to 42% of patients in the cohorts. During 6 months of follow-up, cardiovascular events occurred in 4 of 145 patients (3%),³ 22 of 227 patients (6%),⁴ and in 11 of 80 patients (14%).⁵ At 6-month follow-up, exercise stress echocardiography had a NPV of 99.3% and a PPV of 43%.³ Dobutamine/atropine stress echocardiography had a NPV of 95% to 96% and a PPV of 25% to 31%.^4,5

One retrospective review⁶ evaluated exercise and dobutamine/atropine stress echocardiography and stress ECG for 661 low-risk outpatients (48% men, average age 58 years) with atypical chest pain. All patients had normal left ventricular function and no history of coronary artery disease and were followed for an average of 23 months. A positive stress echocardiography test occurred among 16% of the patient population.

During follow-up, 41 of 661 patients (6%) suffered a cardiovascular event. For either exercise or dobutamine/atropine stress echocardiography, the NPV was 99% at 12 months and 96% at 30 months. Patients with a positive stress echocardiography test and a negative stress ECG had a 66% event-free survival rate. Event-free survival rate for patients with a negative stress echocardiography and a positive or negative stress ECG was 97% and 96%, respectively.

Recommendations from others

The American College of Cardiology⁷ gives a Class I recommendation (tests for which there is evidence or general agreement that a given procedure or treatment is useful and effective) for standard echocardiogram for evaluation of chest pain for patients with suspected acute myocardial ischemia (when baseline ECG and other laboratory markers are nondiagnostic and when the study can be obtained during pain or within minutes after its abatement).

It gives a Class IIa recommendation (tests for which there is conflicting evidence or divergence of opinion, but favoring usefulness) to stress echocardiography for the detection of myocardial ischemia for women with an intermediate pretest likelihood of coronary artery disease. It also gives a Class IIa recommendation to stress echocardiography for determining the prognosis of myocardial ischemia among patients for whom ECG assessment is less reliable. This group comprises patients with the following ECG abnormalities: pre-excitation syndrome (such as Wolff-Parkinson-White), electronically paced ventricular rhythm, more than 1 mm of ST depression at rest, and complete left bundle branch block.

Evidence summary

A prospective cohort study¹ evaluated dobutamine or dipyridamole pharmacologic stress echocardiography among 904 primary care patients with either typical or atypical chest pain. Patients were enrolled into the study if they had normal resting wall motion, sinus rhythm, and had no history of coronary artery disease, unstable angina, or PTCA. Patients (average age 61 years, 42% men) were followed for an average of 44 months for primary cardiovascular endpoints (fatal or nonfatal myocardial infarction [MI], unstable angina, PTCA, or cardiac death). A negative or positive stress echocardiography is defined as the absence or presence of abnormal cardiac wall motion on either exercise or pharmacologic stress echocardiography. Eighteen percent of patients had a positive pharmacologic stress echocardiography. Over the length of the study, 81 of 904 patients (9%) suffered a cardiovascular event. Patients with a negative pharmacologic stress echocardiography had a mean annual probability of a cardiovascular event of 0.8% vs 8.5% with a positive pharmacologic stress echocardiography (P<0001). The 4-year infarct-free negative predictive value (NPV) of pharmacologic stress echocardiography was 97%, and the positive predictive value (PPV) was 70%.

A similar prospective cohort study² evaluated 105 patients (50% men) with atypical chest pain in an emergency department setting with either exercise or dobutamine/atropine stress echocardiography. The average patient age was 55 years and follow-up was 2.8 years. Patients were clinically stable, had normal or nondiagnostic electrocardiogram (ECG), normal cardiac enzymes, normal left ventricular function, and no history of coronary artery disease or unstable angina. Cardiovascular endpoints included fatal or nonfatal MI, unstable angina, PTCA, or cardiac death. A total of 7 patients (7%) suffered a cardiovascular event during the follow-up period. Positive stress echocardiography results occurred for 9% of patients. The NPV was 99% and the PPV was 75%.

Three other cohort studies^3-5 evaluated exercise or dobutamine/atropine stress echocardiography for a total of 615 patients (48%–67% men, average age 56–58 years) presenting to an emergency department with classical cardiac or atypical chest pain. Patients had normal or nondiagnostic ECG, negative cardiac enzymes, and either no history of coronary artery disease^3,4 or known coronary artery disease of unknown significance.⁵ A positive stress echocardiography was obtained for 4.8% to 42% of patients in the cohorts. During 6 months of follow-up, cardiovascular events occurred in 4 of 145 patients (3%),³ 22 of 227 patients (6%),⁴ and in 11 of 80 patients (14%).⁵ At 6-month follow-up, exercise stress echocardiography had a NPV of 99.3% and a PPV of 43%.³ Dobutamine/atropine stress echocardiography had a NPV of 95% to 96% and a PPV of 25% to 31%.^4,5

One retrospective review⁶ evaluated exercise and dobutamine/atropine stress echocardiography and stress ECG for 661 low-risk outpatients (48% men, average age 58 years) with atypical chest pain. All patients had normal left ventricular function and no history of coronary artery disease and were followed for an average of 23 months. A positive stress echocardiography test occurred among 16% of the patient population.

During follow-up, 41 of 661 patients (6%) suffered a cardiovascular event. For either exercise or dobutamine/atropine stress echocardiography, the NPV was 99% at 12 months and 96% at 30 months. Patients with a positive stress echocardiography test and a negative stress ECG had a 66% event-free survival rate. Event-free survival rate for patients with a negative stress echocardiography and a positive or negative stress ECG was 97% and 96%, respectively.

Recommendations from others

The American College of Cardiology⁷ gives a Class I recommendation (tests for which there is evidence or general agreement that a given procedure or treatment is useful and effective) for standard echocardiogram for evaluation of chest pain for patients with suspected acute myocardial ischemia (when baseline ECG and other laboratory markers are nondiagnostic and when the study can be obtained during pain or within minutes after its abatement).

It gives a Class IIa recommendation (tests for which there is conflicting evidence or divergence of opinion, but favoring usefulness) to stress echocardiography for the detection of myocardial ischemia for women with an intermediate pretest likelihood of coronary artery disease. It also gives a Class IIa recommendation to stress echocardiography for determining the prognosis of myocardial ischemia among patients for whom ECG assessment is less reliable. This group comprises patients with the following ECG abnormalities: pre-excitation syndrome (such as Wolff-Parkinson-White), electronically paced ventricular rhythm, more than 1 mm of ST depression at rest, and complete left bundle branch block.

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.

Evidence summary

Bronchiolitis is the most common diagnosis among hospitalized infants aged <1 year in the US.¹ It is usually mild with a self-limited course. A 1997 study following 1113 healthy full-term infants through 20 consecutive winter seasons showed a 5% hospitalization rate of all infants with a positive respiratory syncytial virus (RSV) cult\ure (hospitalization rates with other pathogens were not reported), confirming the mild nature of most cases of bronchiolitis.² RSV accounts for 50% to 80% of bronchiolitis, along with other pathogens such as parainfluenza virus, influenza virus, and human metapneumovirus. A recent analysis of Centers for Disease Control and Prevention data from 1979 to 1997 showed that an average of 95 children died annually in the US from bronchiolitis, and 77% of these were aged <1 year (median age at death was 3 months).³

When discrete measures such as vital signs and scoring scales for respiratory distress are compared, infants who have mild disease courses are very similar to those who subsequently have a more severe illness. This, combined with the low incidence of serious illness, lowers the predictive value of any single clinical criteria for hospital admission (including oxygen saturation, respiratory rate, apparent respiratory distress, and day of illness) to the degree that no objective criteria are useful to make a decision for or against hospitalization.^4,5

In 2 good-quality retrospective case-control studies, which enrolled infants with milder disease discharged from emergency departments, no infants returned with illness severe enough to require admission to an intensive care unit (ICU).^5,6 No criteria were found that could predict subsequent severe course and need for admission.

One good-quality prospective study that enrolled 213 infants, younger than 13 months and presenting with bronchiolitis as outpatients found that physician impression of appearance was a better predictor of severe illness than numeric scoring systems such as the Yale Observation Scale or the Clinical Asthma Score.⁷ Pulse oximetry (<95%), prematurity (<34 weeks gestational age), respiratory rate >70/minute, atelectasis, “ill” or “toxic” appearance, and age <3 months were associated with more severe illness (defined as inability to remain alert and active or well hydrated throughout their illness). Oxygen saturation (SaO₂) <95% was the most objective predictor of severity (positive predictive value=87%; negative predictive value=73%). The study population was more ill than what is typical in outpatient settings (42% required admission and 11% required mechanical ventilation); therefore the positive predictive value would be lower in a milder, more typical outpatient population.

In a retrospective case-control study of 542 otherwise healthy full-term infants aged <1 year admitted for bronchiolitis with positive RSV tests, tachypnea (rate >80) and hypoxia (SaO₂<85%) were predictive of the need for pediatric ICU–level care (the specificity for predicting deterioration was 97%, but the sensitivity was only 30%).⁴ The authors concluded that the use of any specific variable for a single patient is limited because of its low sensitivity for detecting the risk of an adverse outcome.

Several studies have attempted to define admission criteria or decision-making tools for admission of these infants, but all used the clinical opinion of the attending pediatrician as their gold standard and many excluded infants discharged within 24 hours, thus limiting their applicability to an outpatient population.^4,7-10 Common criteria in these studies were an SaO₂ ≤93% or history of complicating illness such as congenital heart disease, prematurity, or lung disease, plus the clinical impression of the attending physician.

TABLE
Risk factors for deterioration in infants with bronchiolitis

Recommendations from others

The American Academy of Pediatrics does not have a guideline addressing this issue. The only guideline listed at the National Guidelines Clearinghouse was a 2005 Cincinnati Children’s Hospital Medical Center guideline for managing infants with bronchiolitis; it is grounded in assuring good patient oxygenation and hydration.¹¹ This guideline does not give specific criteria for admission but leaves this decision to the judgment of the physician. It also notes that the benefits of hospitalization center on the ability to closely monitor clinical status (including airway maintenance and hydration) and educating parents. The guideline recommends starting supplemental oxygen when SaO₂ is consistently less than 91% and weaning when higher than 94%.