Adherence to antihypertensives: feasibility of two self-report instruments to investigate medication-taking behaviour in German community pharmacies.

Objective: To design and test the feasibility of two questionnaires in German community pharmacies exploring self-reported adherence to antihypertensives.

Methods: Two self-report questionnaires were designed for patients treated with antihypertensives. The 29-item-questionnaire (long form, LF) was completed by pharmacists interviewing patients who were on the premises filling a prescription. The short form (SF; 19 items) was sent by pharmacies to patients via mail. The acceptance of the instruments by patients and pharmacists as well as the feasibility to measure medication-taking behaviour was investigated. Adherence was investigated by using a modified 5-(LF) or 6-item (SF) Morisky score.

Results: Of 44 community pharmacies contacted, 18 agreed to participate. Patients' response rates were 428/915 (46.8%) for the SF and 249/760 (32.8%) for the LF. One hundred and seventy-nine patients (41.8%) and 70 patients (28.1%) reported adherence problems according to the SF and LF respectively.

Conclusions: To our knowledge, this is the first attempt to develop a self-report instrument for the detection of non-adherence in patients taking antihypertensives in this setting in Germany. Patients were willing to provide detailed information about their medication-taking behaviour. Underestimation of non-adherence may be more pronounced when applying the questionnaire in the pharmacy.