Practicing population-based care in an HMO: evaluation after 18 months.

OBJECTIVE: To determine whether population-based care in a primary care practice results in improvement in compliance with patient care guidelines.
DESIGN: Time series analysis.
SETTING: One primary care practice in Group Health Cooperative of Puget Sound (GHC). PARTICIPANTS: Approximately 1500 enrollees cared for by the practice.
INTERVENTIONS: An ongoing approach to aid clinical planning at the level of the primary care team--population-based care--that depends on clinical guidelines, a computing system to provide epidemiologic data on guideline performance in the practice and reminders, and a process whereby the practice team analyzed and designs interventions for specific clinical problems. MAIN OUTCOME MEASURES: We compared compliance with practice guidelines for preventive care and chronic illness management at baseline and after 18 months in the intervention population with other patients in the same clinic and with patients in GHC as a whole.
RESULTS: Compliance with breast cancer screening and colorectal cancer screening guidelines in the intervention population increased from baseline 32% and 18% respectively. These increases were significantly greater than in the remainder of the clinic or in GHC as a whole.
CONCLUSIONS: The availability of practice-based data, clinical guidelines and a local intervention design process resulted in significant improvements in compliance with patient care guidelines.