German language adaptation of the Cluster Headache Quality of Life Scale (CH-QoL)

Cluster headache (CH) can lead to high disability and reduced quality of life (QoL). QoL should be assessed as an important outcome both in research and in clinical care. The 28-item Cluster Headache Quality of Life Scale (CH-QoL) is a valid self-report questionnaire to assess disease-specific QoL. A German version is lacking. This study aims to develop a German-language version and to determine its psychometric properties.

The CH-QoL was translated into German by two headache experts and blindly back-translated by two professional translators. Additionally, the CH-QoL was tested for comprehensibility by nine persons with CH. In this multi-stage process, linguistic discrepancies were repeatedly discussed in an expert panel and appropriate modifications were conducted to optimize the translation. A cross-sectional online survey, comprising the CH-QoL and further self-report questionnaires such as the Cluster Headache Scales (CHS), yielded a sample of N = 106 persons with CH (53.8% female, M = 45.5 [SD = 11.8] years, 48.1% episodic CH, 51.9% chronic CH, 79.2% currently having recurring CH attacks).

Exploratory factor analysis revealed two clearly interpretable factors ("restriction of activities of daily living", and "impact on mood and interpersonal relationships"), which is in discrepancy to the four factors of the original English version. The model fit was good, with χ²(323) = 590.74, p < .001, RMSEA = 0.088, SRMR = 0.053, TLI = 0.857. Reliability was very good (McDonald's omega ω = 0.97, Subscale/Factor 1: ω = 0.96, Subscale/Factor 2: ω = 0.92). Correlational analyses (correlations with related questionnaires as well as with clinical parameters) confirmed convergent validity.

Since the German version of the CH-QoL has very good psychometric properties, it is suitable for the assessment of disease-specific QoL in people with CH in German-speaking countries.

This study is registered with the German Clinical Trials Register (DRKS-ID: DRKS00028475, registration date 03 March 2022).