Implementing guidelines in general practice. Evaluation of process and outcome of care in chronic diseases.

In a prospective longitudinal study over 21 months the performance of general practitioners and the disease status of their patients was measured during the formulation and implementation of guidelines on follow-up care. Data on 15 general practitioners and on 613 patients with hypertension, 95 with diabetes mellitus, 66 with chronic ischemic heart disease, 115 with chronic respiratory disease, and 17 with osteoarthritis were used for analysis. Performance measures were defined and for each disease a disease status indicator was used. The possibly modifying effect of compliance of the general practitioner, and of patient compliance with the guidelines was taken into account. The general practitioners formulated consensus guidelines on follow-up care and implemented these guidelines in their practices. The implementation was supported by peer review. The performance of general practitioners tended to conform more with the guidelines during the study period, especially with regards to actions that should be performed routinely. There were no major changes in the disease status indicators. Compliant hypertensive patients had a normotensive status more frequently than non-compliant patients. Diabetic patients were more likely to be normoglycaemic when they received care according to guidelines. None of the differences were statistically significant over time.