Do integrated medical groups provide higher-quality medical care than individual practice associations?

Background: The association between the organizational structure of physician groups and health care quality has never been evaluated empirically. Objective: To examine whether integrated medical groups (IMGs) provide higher-quality primary care than individual practice associations (IPAs). Design: Cross-sectional study. Setting: PacifiCare, a large health maintenance organization. Participants: Approximately 1.7 million enrollees of PacifiCare cared for by 119 California physician groups between July 1999 and June 2000. Measurements: The percentage of eligible PacifiCare enrollees who received mammography, Papanicolaou smear screening, chlamydia screening, diabetic eye examination, an asthma controller medication, or a beta-blocker after acute myocardial infarction. Results: Physician groups identified as IMGs, compared with those identified as IPAs, had higher rates of mammography (relative risk, 1.15 [95% CI, 1.01 to 1.33]), Papanicolaou smear screening (relative risk, 2.29 [CI, 1.53 to 3.42]), chlamydia screening (relative risk, 2.17 [CI, 1.04 to 4.55]), and diabetic eye screening (relative risk, 1.55 [CI, 1.28 to 1.88]). Leaders of IMGs were more likely to report using EMRs (37% vs. 2%; P < 0.001) and quality improvement strategies, but these characteristics explained little of the quality differences between IMGs and IPAs. Limitations: Organizational characteristics, including group type, were reported by physician group leaders and not directly assessed. Patient characteristics that could have accounted for some of the observed differences also were not assessed. Conclusions: Patients cared for in IMGs generally received higher-quality primary care than those cared for in IPAs. Having an EMR and implementation of quality improvement strategies did not explain the differences in quality. These findings suggest that physician group type influences health care quality.