Physician practice size and variations in treatments and outcomes: evidence from Medicare patients with AMI.

Little is known about the relationships between physician practice size and patient treatments or outcomes. We examined whether the practice size of attending physicians was related to within-hospital differences in care for Medicare patients with acute myocardial infarction (AMI). We found that patients treated by solo physicians were less likely to receive cardiac catheterization and angioplasty within a day of admission and more likely to die than other patients in the same hospital, even after a number of patient and physician characteristics were taken into account. These differences suggest that solo practitioners are less likely to follow guidelines calling for quick use of angioplasty.