New evidence for construct validity and interpretability of the German Quality of Life in Hand Eczema Questionnaire (QOLHEQ).

Background: The Quality of Life in Hand Eczema Questionnaire (QOLHEQ) is a disease-specific instrument used to assess health-related quality of life (HRQoL) in patients with hand eczema according to the domains of (a) symptoms, (b) emotions, (c) functioning, and (d) treatment/prevention. Today it is not clear what a single score of the QOLHEQ in its German-language version means to a patient.

Objectives: It was the aim of this study to band the QOLHEQ score to an anchor question (AQ) in order to obtain meaningful categories of the QOLHEQ to aid its interpretation. In addition, we assessed the minimal important change (MIC) by using anchor- and distribution-based methods.

Methods: Overall n = 440 hand eczema patients were included in the study. Mean age was 47.5 years (SD 11.9); 38.4% of the sample were female.

Results: With a weighted kappa of 0.62, the total QOLHEQ score showed the best agreement for the following band: QOLHEQ of <17 = no impairment; QOLHEQ of 18-28 = slight impairment; QOLHEQ of 29-41 = moderate impairment; QOLHEQ of 42-79 = severe impairment; and QOLHEQ of >79 = very severe impairment. The MIC for the total score was found to be 16.5 points.

Conclusion: This banding represents a standardized means of interpreting the QOLHEQ total score. Our results indicate that a banding study should be performed for each language version of the QOLHEQ.