Development and psychometric evaluation of the German version of the Medication Regimen Complexity Index (MRCI-D)

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.

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.

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.

The number of medications correlated highly and statistically significantly with the MRCI-D score (0.91, P < 0.001), indicating sufficient convergent validity of the instrument. Both inter-rater and test-retest reliability were very high (intraclass correlation coefficients above 0.80 in all cases).

Our results demonstrate that the German version of the MRCI reflects the complexity of therapeutic regimens with similar validity and reliability as the established English version. Thus, it may be a valuable tool to analyse therapeutic regimens in both clinical practice and science.