Profiling resource use by primary-care practices: managed Medicare implications.

Variations in elderly Medicare beneficiaries' health service use are examined using a 100-percent sample of fee-for-service (FFS) claims data from Alabama, Iowa, and Maryland. Provider specialty, group practice type, practice size, and location are found to be significant factors affecting hospital and ambulatory care utilization and cost, after controlling for patient and regional characteristics. These results provide insights into utilization and cost expectations from different types of primary-care gatekeepers as the Medicare managed care market develops.