Organizational and physician characteristics predicting practice style: A study of outpatient care in a large group practice

This dissertation examines the impact of non-clinical factors on physician practice styles in a large group practice. I compared the outpatient resources used for HMO vs. FFS patients during episodes of acute illness when the HMO and FFS patients being compared were treated by the same physicians. I also examined whether the setting--a free-standing branch clinic or the hospital-based main clinic--where physicians practiced lead to different styles of care. In both sets of analyses, I used extensive controls for clinical factors and a variety of non-clinical factors including physician specialty and organizational factors.The study site was one of the 15 largest group practices in the U.S., where 1/3 of the patients were HMO and 2/3 FFS--all treated by the same physicians. The claims data for the HMO and FFS patients were identical. I used an episode approach in which all care rendered during a specified period was recorded, along with who provided it and where it was provided. Seven diseases including ulcer, esophagitis, gastritis, bronchitis, otitis media, eczema and back pain were considered. Based on 3 and 1/2 years of billing records (1986-89), between 1,300 and 46,000 episodes for each disease were obtained. In addition, socio-demographic and health-related information about each patient and organizational and professional information about the physician was obtained. Separate linear regression models with adjustments for case-mix, physician specialty, and organizational factors were used to determine the effect of insurance status and practice location on 5 different measures of resource use including the number of visits, and expenses for clinical, laboratory, and radiology services, and total outpatient costs.The findings indicate that although clinical factors were the most powerful predictors of resource use, both patient insurance type and practice location were significant predictors of practice styles as well. The specific effects of insurance and practice location varied somewhat by disease and types of resources. However, in most instances resource use was lower for episodes involving HMO patients and especially for those treated by physicians located in branch clinics.U of I OnlyETDs are only available to UIUC Users without author permissio