Objectives. This study investigates the levels of participation and the relative association of economic and noneconomic factors on primary care physician participation in the Medicare program.

Methods. Demographic information, participation in Medicare, and attitudes toward both the Medicare program and Medicare patients were collected in a written survey mailed to half the primary care physicians in Iowa. Ordinary least squares and logistic regression analyses were conducted to determine factors associated with the percentage of Medicare patients in a practice and the acceptance of all new Medicare patients, respectively.

Results. Two thirds of physicians were accepting all new Medicare patients, whereas 16% were accepting no new Medicare patients. Factors associated with having a higher percentage of Medicare patients in a practice were as follows: (1) a larger proportion of Medicare recipients in the county, (2) practice as a general internal medicine physician, (3) more years in practice at the current location, (4) greater enjoyment treating elderly patients, (5) less concern about having too many Medicare patients, and (6) a stronger belief that the Medicare program respects their professional judgment. Physicians less concerned about having too many Medicare patients in their practice and physicians in counties with a higher percentage of Medicare patients were significantly more likely to accept all new Medicare patients.

Conclusions. These results suggest that as Medicare reforms are discussed, careful consideration of the impact of these reforms on noneconomic issues is important to ensure adequate physician participation and access for elderly patients through the Medicare program.