Descriptive analysis of mail interventions with physicians and patients to improve adherence with antihypertensive and antidiabetic medications in a mixed-model managed care organization of commercial and Medicare members.

Abstract

Medication nonadherence is a major concern for many health care stakeholders. Improving medication adherence in health plan members who have both hypertension and diabetes is essential for the successful management of these chronic diseases, with anticipated outcomes in decreased health care utilization, all-cause mortality and cost. To (a) identify patients who are potentially nonadherent to antidiabetic or antihypertensive agents within 1 managed care organization and (b) determine the relationship of rates of medication nonadherence with 2 mail intervention programs that involved quarterly medication-specific profiles of patients with potential nonadherence sent to primary care physicians (PCPs) and general medication adherence letters sent to patients with potential nonadherence. The study sample consisted of commercial members, Medicare Advantage-Prescription Drug Plan (MA-PD) members and Medicare Prescription Drug Plan (PDP) members who filled prescriptions for antihypertensive and antidiabetic medications and utilized their managed care pharmacy benefit during each measurement quarter (3 months) in the 2-year study period. Nonadherence was defined as a medication possession ratio (MPR) less than 77.0% for 1 or more antihypertensives and/or antidiabetic medications for each standalone calendar quarter. The first intervention, letters to PCPs with patient-specific medication profiles for 2008 Q2, began 6-8 weeks after 2008 Q2 and continued for each standalone calendar quarter through the end of the study period in 2010 Q1 (January 1, 2010, through March 31, 2010). We assumed that patient care was managed by PCPs for hypertension and diabetes treatment. The medication profile also included antihyperlipidemic medication claims information, but there was no adherence analysis performed for antihyperlipidemic medications. The second intervention, letters sent to potentially nonadherent patients, began 6-8 weeks after 2009 Q1 for patients with MPR less than 77% for 1 or more antidiabetic or antihypertensive medications in 2009 Q1 and continued for each standalone calendar quarter through the end of the study period in 2010 Q1. Because there were 2 different interventions, 2 baseline adherence rates were calculated, for 2008 Q2 for the PCP mailing and for 2009 Q1 for the patient mailing. Compared with the baseline nonadherence rate in 2008 Q2 (35.6%), a small increase in nonadherence was observed in 2008 Q3 (36.4%), following by 6 calendar quarters of lower rates of nonadherence with a 27.7% nonadherence rate in the last measurement period in 2010 Q1. Compared with the nonadherence rate of 30.8% in baseline 2 (2009 Q1), the patient mailings were associated with small increases in nonadherence to 31.4% in 2009 Q2 and 31.1% in 2009 Q3, respectively, followed by lower nonadherence rates in 2009 Q4 (29.2%) and 2010 Q1 (27.7%). A 2-part intervention that involved mailings to PCPs for patients with both diabetic and antihypertensive medications who were potentially nonadherent to at least 1 medication, followed 9 months later by a general mailing sent to these potentially nonadherent patients regarding medication adherence, was associated with apparent improvement. However, the effect of the 2-part intervention on medication nonadherence could not be isolated because of coincident disease management interventions in diabetes and hypertension during the 2-year study period.