There is limited evidence that contracts can potentially contribute to improving adherence, but there is insufficient evidence from large, good quality studies to routinely recommend contracts for improving adherence to treatment or preventive health regimens.
Influencing adherence among hypertensives.
In the treatment of hypertension, problems of nonadherence and consequent poor blood pressure control are particularly severe. Alternative intervention strategies were compared to explore means of improving adherence and lowering blood pressures. In a 3 x 4 repeated measures analysis of variance design, 115 patients were randomly selected and randomly assigned to one of three treatment modalities (routine clinic care, patient education, and contingency contracting) and were followed over four clinic visits. Subjects' knowledge about hypertension and its management, adherence to requests for regular medical follow-up, and blood pressure levels were measured. Patient education was not effective in lowering blood pressures; it produced an untoward outcome, a dropout rate higher than that for patients receiving only routine clinic care. However, contingency contracting was an effective intervention strategy for improving patient knowledge, F (1,59) = 51.32, p less than .0001; adherence to requests for regular medical care, Max L (2) = 25.9, p less than .0001; and decreasing diastolic blood pressures, F (2,49) = 3.39, p less than .05.