Translation, Cross-Cultural Adaptation and Validation of the Lymphedema Quality of Life Questionnaire (LYMQOL) in German-Speaking Patients with Lymphedema of the Lower Limbs.

The LYMQOL Leg questionnaire is the most widely used, evidence-based tool for the assessment of health-related quality of life (HRQoL) in patients with lower limb lymphedema (LLL). It has been translated into several languages, but a German version is currently lacking. The aim of our study was to validate a German translation of LYMQOL Leg. Translation and cross-cultural adaptation were performed in accordance with ISPOR principles. A total of 103 patients with LLL from Germany, Austria, and Switzerland were interviewed twice. The content and face validity assessments indicated that the German LYMQOL Leg questionnaire was acceptable for interviewing patients with lymphedema. Comparing the LYMQOL Leg with the SF-36 demonstrated good construct validity. Reliability determined by the test-retest procedure was good (intra-class-correlation coefficients 0.68-0.92). Cronbach's alpha values ranged from 0.76 to 0.90 in both interviews, showing an acceptable internal consistency. The four domains of the questionnaire reached a cumulative variance of 52.7% in the factor analysis. The association between the lymphedema stages and the LYMQOL Leg domain scores was not significant. In conclusion, the validity of the German version of LYMQOL Leg, called , was confirmed and thus represents a suitable tool for measuring HRQoL in German-speaking patients with LLL.