Validation of a short-form of the Freiburg Life Quality Assessment for lymphoedema (FLQA-LS) instrument

Background Chronic lymphoedema (CLE) is a burdensome disease of multiple causes leading to significant reductions in health-related quality of life (HRQoL). A specific method to assess HRQoL is the Freiburg Life Quality Assessment for lymphoedema (FLQA-L), which consists of 92 items. Objectives To develop and validate a short form of the FLQA-L with improved psychometric properties and feasibility. Methods The FLQA-L validation data were reanalysed by patients and experts. The application of factor analysis enabled the exclusion of lower-load items. An optimized short version of the questionnaire (FLQA-LS) with 33 items was generated and tested in a validation study on patients with different forms of CLE. Results In total, 348 patients with CLE of the upper or lower extremities were included (mean age 57.3 years, range 24-89; 90.8% female), and data from 301 patients could be analysed. Overall, 42.8% of the patients had secondary lymphoedema, 23.6% had primary lymphoedema, 9.5% had lipoedema and 24.1% had lipolymphoedema. The lower extremities were mostly affected (64.4% of the patients presented with leg involvement and 17.5% with both arm and leg impairment). The FLQA-LS showed good internal consistency, with high Cronbach's alpha in the subscales and in the global scale ranging between 0.79 and 0.94. Regarding convergent validity, a good correlation was found with the general HRQoL questionnaire EQ-5D (r = 0.72, P < 0.001). Conclusions FLQA-LS is an improved version of the FLQA-L questionnaire for chronic lymphoedema. It demonstrated validity and feasibility and can be easily used in clinical practice and research studies.