Adaptation of the Herdecke Quality of Life questionnaire towards quality of life of cancer patients.

Although instruments for the measurement of quality of life (QoL) do exist for cancer patients, factors like sleepiness or digestion are only marginally addressed. We intended to adapt the Herdecke Quality of Life (HLQ) towards these aspects in a multi-centre cross-sectional validation study. A group of 293 subjects [79% female, age: 55.9 +/- 13.4 years; 146 cancer patients, 28 patients with rheumatic diseases and a healthy control group (n = 119)]. Structural relations between the items were detected by factor and reliability analyses. For external validation, correlations with the hospital anxiety and depression scale (HADS), self-regulation score (SRS) and the Marburger short questionnaire on chronotypology (MQC) were performed, and test-retest reliability was calculated. Factor analysis found three sub-scales: physical abilities (PA) (Cronbach's alpha = 0.90), sleep quality (SQ) (Cronbach's alpha = 0.89) and digestive well-being (DWB) (Cronbach's alpha = 0.80). Sleep quality correlated well with HADS-anxiety (r =-0.52), PA with HADS-depression (r =-0.49). We found moderate correlations of PA and SQ with SRS, while the HLQ scales did not correlate with the MQC. Analysis of test-retest reliability resulted in values of r = 0.757 for PA, r = 0.715 for SQ and r = 0.603 for DWB. The HLQ-cancer suits to measure unique features of cancer-related QoL aspects. In future studies it has to be tested in larger samples of cancer patients.