Rate of Case Reporting, Physician Compliance, and Practice Volume in a Practice-Based Research Network Study
STUDY DESIGN: This was a prospective observational cohort study of participants in a practice-based research network who submitted data on 231 patients with dyspepsia from a total of 45,337 patient encounters over a 53-week period. Reporting of individual cases involved use of a relatively high-burden data instrument. Outcome measures were compared using rank correlation.
POPULATION: We included 18 physicians in a Wisconsin research network study on initial management of dyspepsia in primary care settings.
OUTCOMES MEASURED: The outcomes were the rate of dyspepsia visits, average weekly patient volume, and self-reported compliance with the study protocol for each physician.
RESULTS: A significant negative correlation existed between physician patient volume and the reported rate of dyspepsia visits. Self-reported compliance with the protocol was negatively correlated with patient volume and positively correlated with the reported rate of dyspepsia visits.
CONCLUSIONS: Practice volume may influence the results in practice-based research. Investigators using practice-base research networks need to consider the complexity of their protocols and should be cognizant of compliance-sensitive measures.
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.
