Rate of Case Reporting, Physician Compliance, and Practice Volume in a Practice-Based Research Network Study

Common medical problems, especially those that are self-limited or in their early phases, can be best studied in community practice settings where they are usually diagnosed and managed. Practice-based research provides one method to conduct studies of these problems. Often practice-based research physicians are linked together in practice-based research networks (PBRNs), thus forming, in effect, laboratories of community practices.^1-3

The methodologic limitations of these laboratories are of concern and have not been extensively explored. Although it has been adequately demonstrated that the patient populations and the problems addressed in participating practices are comparable to patients and problems in the general population,^4-6 the question of the selection bias of the clinicians has been raised.⁴

As research involvement can be a costly endeavor for the individual physician,⁷ participation in a research protocol—to some extent—may be related to the intensity of practice (ie, the volume of patients seen and services provided). It has been shown that high-volume practices differ from low-volume practices⁸ in that high-volume practices provide lower rates of preventive services and generate lower patient satisfaction. One may anticipate that physicians with more discretionary time (ie, fewer patients) may be better able to fully participate in research activities. There have been no direct studies of the impact of practice volume on the reporting of medical problems and compliance in research studies. This study, conducted as part of a larger Wisconsin Research Network (WReN) study of dyspepsia in primary care settings, is a first step in that direction.

Methods

Eighteen family physicians, making up the Practice-Based Research Group of WReN practices, volunteered to participate in a study of the initial management of dyspepsia in primary care.⁹ As part of the study protocol, participants were requested to record the number of adult patients presenting with dyspepsia and the total number of patients seen in their clinic for each week of the 12-month study. Dyspepsia was defined as pain in the upper abdomen lasting for at least 2 weeks and not attributable to cardiac or pulmonary disease or trauma. Data was collected for both initial and follow-up visits. Participants were instructed to complete a 1-page data instrument for each dyspeptic patient at the time of the visit. Each instrument contained 68 data elements and took up to 5 minutes to complete. Data forms were mailed to the study coordinator on a monthly basis. Data collection began on January 30, 1995, and continued through February 2, 1996.

An average weekly patient volume was calculated for each physician, as was the reported rate of dyspepsia visits in their practice. The patient volume was estimated for each physician by summing the weekly patient totals and dividing by the number of weeks during which the physician saw patients in the clinic and participated in the study. The reported rate of dyspepsia visits for each physician was estimated as the total number of patient visits reported meeting the study criteria for dyspepsia divided by the total number of patients seen during the study period.

Following completion of primary data collection, a demographic questionnaire was sent out to all 18 participants. The questionnaire distribution occurred approximately 4 months after data collection and during a chart review phase of the primary study. The chart review was performed by a research assistant and did not involve the participating physicians. One question, included to assess compliance with the study protocol, asked, “On a 10-point scale, how compliant were you at recording data for all qualifying dyspepsia patients during the weeks that you were involved with this study?” Responses were circled on a scale from 1 (poor) to 10 (perfect). Type of practice (solo, group multispecialty, or academic) was also obtained. Seventeen of the 18 questionnaires were completed and returned.

MINITAB was used for statistical analyses. Descriptive statistics were calculated for the outcome variables. Because data for reported rate of dyspepsia visits and compliance were not normally distributed, Spearman rank correlation (“ = 0.05) was used to test the hypotheses that practice volume, protocol compliance, and reported rate of dyspepsia visits were correlated. The one solo practitioner was placed with the group practice physicians because of a high level of similarity in all outcome variables. Because differences were noted among the practice types, the Kruskal-Wallis test was used to assess differences in patient volume, compliance, and reported rate of dyspepsia visits.

Results

The average participant in this study was a 46-year-old male physician who had been in practice for 17 years and saw 61.5 patients per week Table w1. Eight physicians were located in group practices, while 5 were in multispecialty and 3 were in academic practices. The mean reported rate of dyspepsia visits was 7.7 cases per 1000 patient visits. Initial dyspepsia visits accounted for 118 of the 231 reported visits for dyspepsia (0.51%), with a total of 45,337 patient visits recorded by participating physicians.

The average participant recorded visits over 43.2 weeks of the possible 53-week study (81.5% overall participation rate). The average self-reported compliance with the study protocol was 6.7 on a 10-point scale but with a very wide range (from 1 to 10). Significant differences among practice types were found in patient volume, reported rate of dyspepsia visits, and self-reported compliance Table 2. Participants from group practices had the highest patient volumes but the lowest rate of dyspepsia visits and compliance. Academic physicians saw the least number of patients but had the highest reported rate of dyspepsia visits and compliance.

Significant negative rank correlations were found to exist between patient volume and reported rate of dyspepsia visits (Figure 1: rs = -0.548; P .05) and between patient volume and compliance with protocol (Figure 2: rs = -0.490; P .05). A significant positive rank correlation was found between compliance with protocol and rate of dyspepsia visits (Figure 3 (: rs = 0.551; P .05). No significant correlation existed between the number of weeks of participation and patient volume (rs = -0.303), rate of dyspepsia visits (rs = 0.065), or compliance with protocol (rs = 0.415).

Discussion

Practice volume can have a significant effect on physicians’ reporting rates in practice-based studies. The rate of dyspepsia visits, as measured by the identification of patients meeting study criteria and having a completed data form, was negatively related to the number of patients seen per week by the physician. Practice volume appears to be linked to reporting by way of compliance. As an extension, it appears that physicians are generally accurate in self-assessment of their compliance with a protocol.

Although previous evaluations of PBRNs have demonstrated high levels of accuracy within reported data,¹⁰ the results reported here are somewhat disturbing. If other studies show similar results, the idea that PBRNs can assess prevalence of medical conditions could be called into question. Also, there may be a bias in the higher? volume practices for patients with more severe symptoms to be reported in preference to those with less “attention getting” symptoms, or in low-volume practices to seek out problems for which the patient did not seek attention. Consequently, even when a medical problem is identified, there may be patient selection bias toward those with more or less severe symptoms.

Additional burden and lack of practice support were common reasons for withdrawing from participation in PBRNs.¹¹ Overall participation and compliance with a research protocol, therefore, is likely related to the complexity of that protocol. While the reported rate of dyspepsia visits was negatively related to practice volume, the simple reporting of a weekly tally of patients seen in clinic was not. Consequently, compliance-sensitive measurements (eg, prevalence) may need simple time-efficient protocols. For example, full compliance with the protocol for the approximately 1050 physicians currently involved in the Centers for Disease Control and Prevention US Influenza Sentinel Physician Surveillance Network requires less than 3 minutes per week. This surveillance network for monitoring prevalence of influenza-like illness is a highly accurate, timely, and valued component of influenza surveillance.¹² Other enhancements for study protocols may include decreased periods for data gathering, use of intermittent reporting, and use of other office staff for case identification.

Limitations

This study is limited by a potential lack of generalizability. It is an observational study of physician behavior around a complex and relatively high-burden data collection instrument. There were no true standards regarding prevalence of dyspepsia at any location, thus allowing for the possibility that patient populations differed significantly among sites. Self-reported compliance with the research protocol was based on recall 4 months after the end of the data collection period. Also, some of the effect attributable to patient volume could alternatively result from the types of physicians involved in this study.

Academic physicians, with low practice volumes, may be more likely to be compliant with research protocols in general, regardless of their practice volumes. Because of the small sample size, however, this alternate hypothesis cannot be examined independently. With the exclusion of the academic physicians, relationships between the variables demonstrated the same trends, but the Spearman rank correlations were no longer significant (n = 14; patient volume vs rate: rs = -0.345; patient volume vs compliance: rs = -0.187; compliance vs rate: rs = 0.379).

This study does, however, challenge other investigators using PBRNs to revisit suitable data to determine similar patterns. Also, a simple assessment of participant compliance might prove to be an essential enhancement of future practice-based research.

Conclusions

Even encumbered with potential methodologic dilemmas, practice-based research studies may be the only way to approach many common medical issues in the context of the communities in which they occur.^1-3 For example, while selection bias in reporting of dyspepsia is clearly a problem in this example, the selection bias is still far less severe than it would be in the gastrointestinal specialty clinic of a referral center. Likewise, if nonreferred conditions are to be tracked over extensive periods of time, the use of community settings is essential, as was done with a recent longitudinal study of depression.¹³

Acknowledgments

Funding for this study was provided through a grant from the American Academy of Family Physicians. We thank the following participants of the WReN Practice-Based Research Group: R. Baldwin, E. Barr, D. Baumgardner, A. Berlage, M. Chin, D. Erickson, R. Erickson, G. Gay, M. Grajewski, D. Hahn, T. Hankey, D. Madlon-Kay, A. Marquis, E. Ott, D. Pine, and L. Radant.

Common medical problems, especially those that are self-limited or in their early phases, can be best studied in community practice settings where they are usually diagnosed and managed. Practice-based research provides one method to conduct studies of these problems. Often practice-based research physicians are linked together in practice-based research networks (PBRNs), thus forming, in effect, laboratories of community practices.^1-3

The methodologic limitations of these laboratories are of concern and have not been extensively explored. Although it has been adequately demonstrated that the patient populations and the problems addressed in participating practices are comparable to patients and problems in the general population,^4-6 the question of the selection bias of the clinicians has been raised.⁴

As research involvement can be a costly endeavor for the individual physician,⁷ participation in a research protocol—to some extent—may be related to the intensity of practice (ie, the volume of patients seen and services provided). It has been shown that high-volume practices differ from low-volume practices⁸ in that high-volume practices provide lower rates of preventive services and generate lower patient satisfaction. One may anticipate that physicians with more discretionary time (ie, fewer patients) may be better able to fully participate in research activities. There have been no direct studies of the impact of practice volume on the reporting of medical problems and compliance in research studies. This study, conducted as part of a larger Wisconsin Research Network (WReN) study of dyspepsia in primary care settings, is a first step in that direction.

Methods

Eighteen family physicians, making up the Practice-Based Research Group of WReN practices, volunteered to participate in a study of the initial management of dyspepsia in primary care.⁹ As part of the study protocol, participants were requested to record the number of adult patients presenting with dyspepsia and the total number of patients seen in their clinic for each week of the 12-month study. Dyspepsia was defined as pain in the upper abdomen lasting for at least 2 weeks and not attributable to cardiac or pulmonary disease or trauma. Data was collected for both initial and follow-up visits. Participants were instructed to complete a 1-page data instrument for each dyspeptic patient at the time of the visit. Each instrument contained 68 data elements and took up to 5 minutes to complete. Data forms were mailed to the study coordinator on a monthly basis. Data collection began on January 30, 1995, and continued through February 2, 1996.

An average weekly patient volume was calculated for each physician, as was the reported rate of dyspepsia visits in their practice. The patient volume was estimated for each physician by summing the weekly patient totals and dividing by the number of weeks during which the physician saw patients in the clinic and participated in the study. The reported rate of dyspepsia visits for each physician was estimated as the total number of patient visits reported meeting the study criteria for dyspepsia divided by the total number of patients seen during the study period.

Following completion of primary data collection, a demographic questionnaire was sent out to all 18 participants. The questionnaire distribution occurred approximately 4 months after data collection and during a chart review phase of the primary study. The chart review was performed by a research assistant and did not involve the participating physicians. One question, included to assess compliance with the study protocol, asked, “On a 10-point scale, how compliant were you at recording data for all qualifying dyspepsia patients during the weeks that you were involved with this study?” Responses were circled on a scale from 1 (poor) to 10 (perfect). Type of practice (solo, group multispecialty, or academic) was also obtained. Seventeen of the 18 questionnaires were completed and returned.

MINITAB was used for statistical analyses. Descriptive statistics were calculated for the outcome variables. Because data for reported rate of dyspepsia visits and compliance were not normally distributed, Spearman rank correlation (“ = 0.05) was used to test the hypotheses that practice volume, protocol compliance, and reported rate of dyspepsia visits were correlated. The one solo practitioner was placed with the group practice physicians because of a high level of similarity in all outcome variables. Because differences were noted among the practice types, the Kruskal-Wallis test was used to assess differences in patient volume, compliance, and reported rate of dyspepsia visits.

Results

The average participant in this study was a 46-year-old male physician who had been in practice for 17 years and saw 61.5 patients per week Table w1. Eight physicians were located in group practices, while 5 were in multispecialty and 3 were in academic practices. The mean reported rate of dyspepsia visits was 7.7 cases per 1000 patient visits. Initial dyspepsia visits accounted for 118 of the 231 reported visits for dyspepsia (0.51%), with a total of 45,337 patient visits recorded by participating physicians.

The average participant recorded visits over 43.2 weeks of the possible 53-week study (81.5% overall participation rate). The average self-reported compliance with the study protocol was 6.7 on a 10-point scale but with a very wide range (from 1 to 10). Significant differences among practice types were found in patient volume, reported rate of dyspepsia visits, and self-reported compliance Table 2. Participants from group practices had the highest patient volumes but the lowest rate of dyspepsia visits and compliance. Academic physicians saw the least number of patients but had the highest reported rate of dyspepsia visits and compliance.

Significant negative rank correlations were found to exist between patient volume and reported rate of dyspepsia visits (Figure 1: rs = -0.548; P .05) and between patient volume and compliance with protocol (Figure 2: rs = -0.490; P .05). A significant positive rank correlation was found between compliance with protocol and rate of dyspepsia visits (Figure 3 (: rs = 0.551; P .05). No significant correlation existed between the number of weeks of participation and patient volume (rs = -0.303), rate of dyspepsia visits (rs = 0.065), or compliance with protocol (rs = 0.415).

Discussion

Practice volume can have a significant effect on physicians’ reporting rates in practice-based studies. The rate of dyspepsia visits, as measured by the identification of patients meeting study criteria and having a completed data form, was negatively related to the number of patients seen per week by the physician. Practice volume appears to be linked to reporting by way of compliance. As an extension, it appears that physicians are generally accurate in self-assessment of their compliance with a protocol.

Although previous evaluations of PBRNs have demonstrated high levels of accuracy within reported data,¹⁰ the results reported here are somewhat disturbing. If other studies show similar results, the idea that PBRNs can assess prevalence of medical conditions could be called into question. Also, there may be a bias in the higher? volume practices for patients with more severe symptoms to be reported in preference to those with less “attention getting” symptoms, or in low-volume practices to seek out problems for which the patient did not seek attention. Consequently, even when a medical problem is identified, there may be patient selection bias toward those with more or less severe symptoms.

Additional burden and lack of practice support were common reasons for withdrawing from participation in PBRNs.¹¹ Overall participation and compliance with a research protocol, therefore, is likely related to the complexity of that protocol. While the reported rate of dyspepsia visits was negatively related to practice volume, the simple reporting of a weekly tally of patients seen in clinic was not. Consequently, compliance-sensitive measurements (eg, prevalence) may need simple time-efficient protocols. For example, full compliance with the protocol for the approximately 1050 physicians currently involved in the Centers for Disease Control and Prevention US Influenza Sentinel Physician Surveillance Network requires less than 3 minutes per week. This surveillance network for monitoring prevalence of influenza-like illness is a highly accurate, timely, and valued component of influenza surveillance.¹² Other enhancements for study protocols may include decreased periods for data gathering, use of intermittent reporting, and use of other office staff for case identification.

Limitations

This study is limited by a potential lack of generalizability. It is an observational study of physician behavior around a complex and relatively high-burden data collection instrument. There were no true standards regarding prevalence of dyspepsia at any location, thus allowing for the possibility that patient populations differed significantly among sites. Self-reported compliance with the research protocol was based on recall 4 months after the end of the data collection period. Also, some of the effect attributable to patient volume could alternatively result from the types of physicians involved in this study.

Academic physicians, with low practice volumes, may be more likely to be compliant with research protocols in general, regardless of their practice volumes. Because of the small sample size, however, this alternate hypothesis cannot be examined independently. With the exclusion of the academic physicians, relationships between the variables demonstrated the same trends, but the Spearman rank correlations were no longer significant (n = 14; patient volume vs rate: rs = -0.345; patient volume vs compliance: rs = -0.187; compliance vs rate: rs = 0.379).

This study does, however, challenge other investigators using PBRNs to revisit suitable data to determine similar patterns. Also, a simple assessment of participant compliance might prove to be an essential enhancement of future practice-based research.

Conclusions

Even encumbered with potential methodologic dilemmas, practice-based research studies may be the only way to approach many common medical issues in the context of the communities in which they occur.^1-3 For example, while selection bias in reporting of dyspepsia is clearly a problem in this example, the selection bias is still far less severe than it would be in the gastrointestinal specialty clinic of a referral center. Likewise, if nonreferred conditions are to be tracked over extensive periods of time, the use of community settings is essential, as was done with a recent longitudinal study of depression.¹³

Acknowledgments

Funding for this study was provided through a grant from the American Academy of Family Physicians. We thank the following participants of the WReN Practice-Based Research Group: R. Baldwin, E. Barr, D. Baumgardner, A. Berlage, M. Chin, D. Erickson, R. Erickson, G. Gay, M. Grajewski, D. Hahn, T. Hankey, D. Madlon-Kay, A. Marquis, E. Ott, D. Pine, and L. Radant.

Common medical problems, especially those that are self-limited or in their early phases, can be best studied in community practice settings where they are usually diagnosed and managed. Practice-based research provides one method to conduct studies of these problems. Often practice-based research physicians are linked together in practice-based research networks (PBRNs), thus forming, in effect, laboratories of community practices.^1-3

The methodologic limitations of these laboratories are of concern and have not been extensively explored. Although it has been adequately demonstrated that the patient populations and the problems addressed in participating practices are comparable to patients and problems in the general population,^4-6 the question of the selection bias of the clinicians has been raised.⁴

As research involvement can be a costly endeavor for the individual physician,⁷ participation in a research protocol—to some extent—may be related to the intensity of practice (ie, the volume of patients seen and services provided). It has been shown that high-volume practices differ from low-volume practices⁸ in that high-volume practices provide lower rates of preventive services and generate lower patient satisfaction. One may anticipate that physicians with more discretionary time (ie, fewer patients) may be better able to fully participate in research activities. There have been no direct studies of the impact of practice volume on the reporting of medical problems and compliance in research studies. This study, conducted as part of a larger Wisconsin Research Network (WReN) study of dyspepsia in primary care settings, is a first step in that direction.

Methods

Eighteen family physicians, making up the Practice-Based Research Group of WReN practices, volunteered to participate in a study of the initial management of dyspepsia in primary care.⁹ As part of the study protocol, participants were requested to record the number of adult patients presenting with dyspepsia and the total number of patients seen in their clinic for each week of the 12-month study. Dyspepsia was defined as pain in the upper abdomen lasting for at least 2 weeks and not attributable to cardiac or pulmonary disease or trauma. Data was collected for both initial and follow-up visits. Participants were instructed to complete a 1-page data instrument for each dyspeptic patient at the time of the visit. Each instrument contained 68 data elements and took up to 5 minutes to complete. Data forms were mailed to the study coordinator on a monthly basis. Data collection began on January 30, 1995, and continued through February 2, 1996.

An average weekly patient volume was calculated for each physician, as was the reported rate of dyspepsia visits in their practice. The patient volume was estimated for each physician by summing the weekly patient totals and dividing by the number of weeks during which the physician saw patients in the clinic and participated in the study. The reported rate of dyspepsia visits for each physician was estimated as the total number of patient visits reported meeting the study criteria for dyspepsia divided by the total number of patients seen during the study period.

Following completion of primary data collection, a demographic questionnaire was sent out to all 18 participants. The questionnaire distribution occurred approximately 4 months after data collection and during a chart review phase of the primary study. The chart review was performed by a research assistant and did not involve the participating physicians. One question, included to assess compliance with the study protocol, asked, “On a 10-point scale, how compliant were you at recording data for all qualifying dyspepsia patients during the weeks that you were involved with this study?” Responses were circled on a scale from 1 (poor) to 10 (perfect). Type of practice (solo, group multispecialty, or academic) was also obtained. Seventeen of the 18 questionnaires were completed and returned.

MINITAB was used for statistical analyses. Descriptive statistics were calculated for the outcome variables. Because data for reported rate of dyspepsia visits and compliance were not normally distributed, Spearman rank correlation (“ = 0.05) was used to test the hypotheses that practice volume, protocol compliance, and reported rate of dyspepsia visits were correlated. The one solo practitioner was placed with the group practice physicians because of a high level of similarity in all outcome variables. Because differences were noted among the practice types, the Kruskal-Wallis test was used to assess differences in patient volume, compliance, and reported rate of dyspepsia visits.

Results

The average participant in this study was a 46-year-old male physician who had been in practice for 17 years and saw 61.5 patients per week Table w1. Eight physicians were located in group practices, while 5 were in multispecialty and 3 were in academic practices. The mean reported rate of dyspepsia visits was 7.7 cases per 1000 patient visits. Initial dyspepsia visits accounted for 118 of the 231 reported visits for dyspepsia (0.51%), with a total of 45,337 patient visits recorded by participating physicians.

The average participant recorded visits over 43.2 weeks of the possible 53-week study (81.5% overall participation rate). The average self-reported compliance with the study protocol was 6.7 on a 10-point scale but with a very wide range (from 1 to 10). Significant differences among practice types were found in patient volume, reported rate of dyspepsia visits, and self-reported compliance Table 2. Participants from group practices had the highest patient volumes but the lowest rate of dyspepsia visits and compliance. Academic physicians saw the least number of patients but had the highest reported rate of dyspepsia visits and compliance.

Significant negative rank correlations were found to exist between patient volume and reported rate of dyspepsia visits (Figure 1: rs = -0.548; P .05) and between patient volume and compliance with protocol (Figure 2: rs = -0.490; P .05). A significant positive rank correlation was found between compliance with protocol and rate of dyspepsia visits (Figure 3 (: rs = 0.551; P .05). No significant correlation existed between the number of weeks of participation and patient volume (rs = -0.303), rate of dyspepsia visits (rs = 0.065), or compliance with protocol (rs = 0.415).

Discussion

Practice volume can have a significant effect on physicians’ reporting rates in practice-based studies. The rate of dyspepsia visits, as measured by the identification of patients meeting study criteria and having a completed data form, was negatively related to the number of patients seen per week by the physician. Practice volume appears to be linked to reporting by way of compliance. As an extension, it appears that physicians are generally accurate in self-assessment of their compliance with a protocol.

Although previous evaluations of PBRNs have demonstrated high levels of accuracy within reported data,¹⁰ the results reported here are somewhat disturbing. If other studies show similar results, the idea that PBRNs can assess prevalence of medical conditions could be called into question. Also, there may be a bias in the higher? volume practices for patients with more severe symptoms to be reported in preference to those with less “attention getting” symptoms, or in low-volume practices to seek out problems for which the patient did not seek attention. Consequently, even when a medical problem is identified, there may be patient selection bias toward those with more or less severe symptoms.

Additional burden and lack of practice support were common reasons for withdrawing from participation in PBRNs.¹¹ Overall participation and compliance with a research protocol, therefore, is likely related to the complexity of that protocol. While the reported rate of dyspepsia visits was negatively related to practice volume, the simple reporting of a weekly tally of patients seen in clinic was not. Consequently, compliance-sensitive measurements (eg, prevalence) may need simple time-efficient protocols. For example, full compliance with the protocol for the approximately 1050 physicians currently involved in the Centers for Disease Control and Prevention US Influenza Sentinel Physician Surveillance Network requires less than 3 minutes per week. This surveillance network for monitoring prevalence of influenza-like illness is a highly accurate, timely, and valued component of influenza surveillance.¹² Other enhancements for study protocols may include decreased periods for data gathering, use of intermittent reporting, and use of other office staff for case identification.

Limitations

This study is limited by a potential lack of generalizability. It is an observational study of physician behavior around a complex and relatively high-burden data collection instrument. There were no true standards regarding prevalence of dyspepsia at any location, thus allowing for the possibility that patient populations differed significantly among sites. Self-reported compliance with the research protocol was based on recall 4 months after the end of the data collection period. Also, some of the effect attributable to patient volume could alternatively result from the types of physicians involved in this study.

Academic physicians, with low practice volumes, may be more likely to be compliant with research protocols in general, regardless of their practice volumes. Because of the small sample size, however, this alternate hypothesis cannot be examined independently. With the exclusion of the academic physicians, relationships between the variables demonstrated the same trends, but the Spearman rank correlations were no longer significant (n = 14; patient volume vs rate: rs = -0.345; patient volume vs compliance: rs = -0.187; compliance vs rate: rs = 0.379).

This study does, however, challenge other investigators using PBRNs to revisit suitable data to determine similar patterns. Also, a simple assessment of participant compliance might prove to be an essential enhancement of future practice-based research.

Conclusions

Even encumbered with potential methodologic dilemmas, practice-based research studies may be the only way to approach many common medical issues in the context of the communities in which they occur.^1-3 For example, while selection bias in reporting of dyspepsia is clearly a problem in this example, the selection bias is still far less severe than it would be in the gastrointestinal specialty clinic of a referral center. Likewise, if nonreferred conditions are to be tracked over extensive periods of time, the use of community settings is essential, as was done with a recent longitudinal study of depression.¹³

Acknowledgments

Funding for this study was provided through a grant from the American Academy of Family Physicians. We thank the following participants of the WReN Practice-Based Research Group: R. Baldwin, E. Barr, D. Baumgardner, A. Berlage, M. Chin, D. Erickson, R. Erickson, G. Gay, M. Grajewski, D. Hahn, T. Hankey, D. Madlon-Kay, A. Marquis, E. Ott, D. Pine, and L. Radant.