Physician-specific variation in medication adherence among diabetes patients

To examine the relationship that the patient has with his/her healthcare practitioner as a factor affecting medication adherence.

Aggregate, physician-level adherence rates for patients were compared in a retrospective, non-case-controlled study of 3777 diabetes patients enrolled in a commercial pharmacy benefits program in a 6-county area in northeast Ohio.

Data for the top prescribing 200 physicians and their 3777 patients were analyzed based on the adherence of their patients to medications for diabetes, statins, and angiotensin-converting enzyme inhibitors/angiotensin receptor blockers (ACEIs/ARBs). Physicians were then separated into adherence quartiles based on the results. Statistical tests for assessing between-group differences were performed. Results were reported for diabetes medication-specific adherence as well as adherence to statins and ACEIs/ARBs.

No appreciable demographic differences were noted between patient or physician groups, including age, sex, race, cost share, and chronic medication use. Statistically significant differences in aggregate physician-specific medication adherence between the best performing and worst performing physician quartiles were identified, with medication adherence rates of 89.5% for the highest performing quartile compared with 68.1% for the lowest performing quartile. Medication adherence for statins and ACEIs/ARBs paralleled the results for diabetes medications: 88.4% versus 73.4% and 89.8% versus 76.9%, respectively. Importantly, significantly fewer patients in the lowest performing physician group had filled prescriptions for statins or ACEIs/ARBs.

Physician-specific factors have an underappreciated impact on medication adherence. A better understanding of these factors may have substantial benefit in improving compliance with treatment and clinical outcomes.