Health related quality of life in stem cell transplantation: clinical and psychometric validation of the questionnaire module, High Dose Chemotherapy (HDC-19).

The objective of this study was to assess the psychometric properties of the HDC-19, a module questionnaire for assessing symptoms and problems of patients undergoing stem cell transplantation (SCT) following high-dose chemotherapy (HDC). It consists of 19 questions and was developed for use in conjunction with EORTC QLQ-C30. Psychometric evaluations were performed according to guidelines recommended by the EORTC. The principal component analyses suggested that nine of the HDC-19 items could be reduced to four components (sexual functioning, future health perspectives, skin irritations and joint/muscle pain). Multitrait scaling analysis showed that most item-scale correlation coefficients met the standards of convergent (>0.40) and discriminant validity. Test-retest reliability coefficients between assessments at inclusion and admission were high, indicating that perceived health status remained virtually unchanged during this period. As expected, correlations between admission and one month after transplantation were considerably lower. The internal consistency of the multi-item scales was also satisfactory, (Cronbach's alpha 0.59-0.87). Overall, the known-groups comparisons showed smaller differences between designated groups than expected. As expected, changes in the HDC-19 mirrored changes in QLQ-C30 'global quality of life'. These results lend support to the validity of the HDC-19 as a supplementary questionnaire for assessing specific health-related quality of life (HRQOL) issues relevant for SCT patients.