Validation of the German version of the Family Reported Outcome Measure (FROM-16) to assess the impact of disease on the partner or family member

Background The Family Reported Outcome Measure (FROM-16) assesses the impact of a patient's chronic illness on the quality of life (QoL) of the patient's partner or family members. The aim of the study was to translate, explore the structure of and validate the FROM-16. Methods The questionnaire was translated from English into German (forward, backward, four independent translators). Six interviews with family members were conducted to confirm the questionnaire for linguistic, conceptual, semantic and experiential equivalence and its practicability. The final German translation was tested for internal consistency, reproducibility and test validity. Criterion validity was tested by correlating the scores of the FROM-16 and the Global Health Scale (GHS). Principal component analysis, factor analysis, and confirmatory factor analysis was used to assess the questionnaire's structure and its domains. Reliability and reproducibility were tested computing the intraclass correlation coefficient (ICC) using one sample t-test for testing the hypothesis that the difference between the scores was not different from zero. Results Overall, 83 family members (61% female, median age: 61 years) completed the questionnaire at two different times (mean interval: 22 days). Internal consistency was good for the FROM-16 scores (Cronbach's alpha for total score = 0.86). In those with stable GHS, the ICC for the total score was 0.87 and the difference was not different from zero (p = 0.262) indicating reproducible results. A bi-factor model with a general factor including all items, and two sub-factors comprising the items from the original 2-factor construct had the best fit. Conclusions The German FROM-16 has good reliability, test validity and practicability. It can be considered as an appropriate and generic tool to measure QoL of a patient's partner or family member. Due to the presence of several cross-loadings we do not recommend the reporting of the scores of the two domains proposed for the original version of FROM-16 when using the German version. Thus, in reporting the results emphasis should be put on the total score. Trial registration: Retrospectively registered: DRKS00021070.