Drug-adherence questionnaires not valid for patients taking blood-pressure-lowering drugs in a primary health care setting.

Purpose: To validate two established questionnaires [Morisky and Medication Adherence Report Scale (MARS-5)] for the measurement of medical adherence of patients treated with antihypertensive drugs in primary care in Germany.

Setting: General practitioners (GPs) and their patients in North Rhine-Westphalia, Germany.

Methods: GPs were asked to recruit 12 consecutive patients using blood-pressure-lowering medication for at least 12 months.