The 8-item Morisky Medication Adherence Scale translated in German and validated against objective and subjective polypharmacy adherence measures in cardiovascular patients Isabelle Arnet PhD, 1 Corina Metaxas MSc, 2 Philipp N. Walter PhD, 1 Donald E. Morisky ScD ScM MSPH 4 and Kurt E. Hersberger PhD 3 1 Senior Scientist, 2 PhD Candidate, 3 Professor, Department of Pharmaceutical Sciences, Pharmaceutical Care Research Group, University of Basel, Basel, Switzerland 4 Professor, Department of Community Health Sciences, UCLA Fielding School of Public Health, Los Angeles, CA, USA Keywords adherence, German version, questionnaire, validation Correspondence Dr Isabelle Arnet Pharmaceutical Care Research Group Department of Pharmaceutical Sciences University of Basel Klingelbergstr. 50 Basel 4056 Switzerland E-mail: isabelle.arnet@unibas.ch Accepted for publication: 17 November 2014 doi:10.1111/jep.12303 Copyright licence statement The copyrights of the instruments remain with the originators. Permission for use is required. Permissions to use the BMQ must be obtained from Rob Horne, University of London. A license agreement to use the MMAS is available from Donald E. Morisky, ScD, ScM, MSPH, Professor, Department of Community Health Sciences, UCLA School of Public Health, 650 Charles E. Young Drive South, Los Angeles, CA 90095-1772; all translation of the MMAS-8 are copyrighted intellectual property and must be obtained from the developer/owner. Abstract 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. Conver- gent 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 medica- tion adherence in cardiovascular patients. It may be useful in patients with chronic therapy for detecting non-adherence. Introduction The assessment of medication adherence in patients is crucial as non-conformity with prescribed drug regimen poses a substantial risk for therapeutic failure, regardless of the underlying disease [1]. Various adherence assessment methods have been used over the past decades, either direct (i.e. with detection of the substance in a biological fluid, thus proving that a dose of a drug was Journal of Evaluation in Clinical Practice ISSN 1365-2753 Journal of Evaluation in Clinical Practice (2015) © 2015 John Wiley & Sons, Ltd. 1