The 8-item Morisky Medication Adherence Scale translated in German and validated against objective and subjective polypharmacy adherence measures in cardiovascular patients

• Published in: Journal of evaluation in clinical practice Vol. 21; no. 2; pp. 271 - 277
• Main Authors: Arnet, Isabelle, Metaxas, Corina, Walter, Philipp N., Morisky, Donald E., Hersberger, Kurt E.
• Format: Journal Article
• Language: English
• Published: England Blackwell Publishing Ltd 01.04.2015
• Subjects: adherence; Aged; Cross-Sectional Studies; Cytochrome P-450 CYP2C19 - genetics; Female; German version; Health Knowledge, Attitudes, Practice; Humans; Male; Medication Adherence - statistics & numerical data; Middle Aged; Platelet Aggregation Inhibitors - administration & dosage; Polypharmacy; Psychometrics; questionnaire; Reproducibility of Results; Surveys and Questionnaires; Translations; validation; German version; questionnaire; adherence; validation
• ISSN: 1356-1294; 1365-2753
• DOI: 10.1111/jep.12303

Rationale, aims and objectives To translate in German the 8‐item Morisky Medication Adherence Scale (MMAS‐8D). To validate it against objective and subjective measures of adherence in cardiovascular patients with polypharmacy. Methods A standard forward‐backward procedure was used to translate the MMAS‐8 into German. Validation took place on a convenience sample of ambulatory patients on chronic antiplatelet therapy between June 2010 and June 2011. Objective adherence was obtained from electronically monitored multi‐drug punch cards. Internal consistency was assessed using Cronbach's alpha coefficient, construct validity using exploratory factor analyses and correlations between MMAS‐8D and related measures. Convergent validity was assessed with a subjective questionnaire about beliefs about medicines (BMQ Specific, two sub‐scales). Results A total of 70 patients were included (mean age 65.7 ± 9.9 years; 31.4% women). The mean score of the MMAS‐8D was 7.5 (SD 0.8; range 4.5–8). Moderate internal consistency (alpha = 0.31) was observed due to multidimensionality of the scale. Factor analysis yielded four components that accounted for 71.7% of the total variance. Convergent validity was supported by significant correlations with BMQ Necessity (r = 0.31, P < 0.01), BMQ Concerns (r = −0.16, P < 0.05) and with electronic adherence reports (U‐values 44 and 471, P < 0.05). Platelet aggregation values were within therapeutic range for 80% of the patients. Blood values of the antiplatelet agent within therapeutic range were associated with a higher MMAS‐8D score (U‐value 125, P < 0.05). Conclusions The German MMAS‐8 appears to be a reliable instrument to catch medication adherence in cardiovascular patients. It may be useful in patients with chronic therapy for detecting non‐adherence.