The feasibility, reliability and validity of the EORTC QLQ-C30 in assessing the quality of life of patients with a symptomatic HIV infection or AIDS (CDC IV)

The objective of this study was to evaluate the feasibility, reliability and validity of the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (the QLQ-C30) in a longitudinal study of the quality of life (QoL) of patients with a symptomatic HIV infection or AIDS. The OLQ-C30 is a 30-item questionnaire composed of five functional subscales. 3 symptom subscales, an overall QoL subscale, and a number of additional single item symptom measures. The questionnaire was administered serially to a sample of 156 Dutch patients. The average time to complete the questionnaire was less than 11 minutes, with most patients requiring no assistance. With one exception (role functioning subscale), the data supported the hypothesized scale structure of the questionnaire. Eight of the 9 subscales met or approached the minimal criterion for reliability (Cronbach's alpha ≤ .70) at baseline and/or follow-up. The validity of the QLQ-C30 was supported by 3 findings: (1) the correlations observed among the subscales. while statistically significant, were of only a moderate magnitude, indicating that distinct components of QoL are being assessed; (2) a number of the subscales could discriminate clearly between patients differing in stage of disease and in Karnofsky Performance Status; and (3) significant changes in QLQ-C30 scores in the expected direction, were observed over time. These results lend support to the QLQ-C30 as a reasonably reliable and valid instrument for assessing the QoL of patients with HIV infection. Additional research is needed to improve the role functioning subscale. to evaluate the QLQ-C30's concurrent validity by comparing it with other available QoL instruments, and to examine more thoroughly its responsiveness to clinically important changes in patients' health status over the entire disease and treatment trajectory.