Background? Several factors contribute to the complexity of pharmacotherapeutic regimens, like the total number of medications to be taken, the number of dosage units to take at a time, dosage frequency, as well as specific directions concerning the administration. The Medication Regimen Complexity Index (MRCI) is a validated instrument developed in English for the measurement of the complexity of a given pharmacotherapeutic regimen. Objectives? Translation of the MRCI into German and evaluation of the translated instrument (MRCI-D) in order to make it more easily accessible for use in German practice and research. Methods? The process of validation included the translation of the English version to German, back-translation into English, comparison of the back-translated and the original versions, pre-tests, and pilot-testing of the German version by three raters using 20 medication regimens for inpatients. The subsequent psychometric evaluation included the calculation of inter-rater and test-retest reliability, as well as the assessment of convergent validity. Results? The number of medications correlated highly and statistically significantly with the MRCI-D score (0.91, P?
