Methods of Pharmacy Claims Data-based Persistence Analyses and Community Pharmacy-based Estimation of Adherence – The Case of Antihypertensives

Abstract

Patients with chronic diseases like hypertension require long-term and continuous pharmacotherapy to achieve positive outcomes shown in randomized controlled trials. However, non-adherence to drug therapy (up to 50%), e.g. to antihypertensives, is a major problem. Three projects exploring persistence and adherence with antihypertensives are, therefore, the focus of the presentation: To evaluate persistence of patients when switched from the brand name ramipril to a generic product – after patent expiry in 2004– the medication possession ratio (MPR) was measured. Claims data for ambulatory prescriptions within the statutory health care system (GKV, www.dapi.de) were evaluated based on more than 80% of German community pharmacies (CP). Although data were not corrected for covariates like age or gender, which are currently not available in the database, or further co-medication, the results suggest that persistence is not negatively affected by physician-induced switching from brand name to generic ramipril – whether patients were treated with monotherapy, fixed combinations with diuretics or both. The focus of our 2nd project is persistence in long-term treatment with antihypertensive drugs. Again, DAPI data warehouse claims data will be analyzed. Persistence rates in patients treated with monotherapy of an angiotensin receptor blocker (ARB), an ACE inhibitor (ACEI), a beta blocker (BB), a diuretic or a fixed combination of an ARB, an ACEI or a BB with a diuretic are measured using different methods: MPR and gaps in filling prescriptions. Results of the persistence analyses will be compared to adherence with medication in CP. To detect problems of patients with their medication potentially leading to non-adherence in a real life setting, we started a pilot study in German community pharmacies in April 2008. Patients with a prescription for a beta blocker, an ACE inhibitor, a diuretic or a fixed combination of the mentioned substances are asked to fill-in a questionnaire. This self-report questionnaire contains adherence- and medication-based questions. Afterwards, blood pressure is measured by the pharmacist. Data-based persistence and CP-based adherence analyses will be combined to explore opportunities to detect non-compliance and to improve adherence in daily practice.