A measure for quality of life assessment in chronic pain: preliminary properties of the WHOQOL-pain.

Chronic pain has a considerable impact on patient-reported outcomes such as quality of life (QoL). To assess QoL in people with chronic pain, a pain and discomfort module (PDM) was developed for use with the WHOQOL-100 and its psychometric properties assessed. Sixteen items covered four facets on pain relief; anger and frustration; vulnerability, fear and worry; and uncertainty. Chronic low back pain patients (n = 133) (age 56; pain duration 85 months; 65% female) completed the WHOQOL-100 and PDM, McGill Pain Questionnaire, and SF-12. The PDM showed good internal consistency reliability (alpha = .88) (alphas .66-.81). Except for anger, all facets associated most strongly with their 'parent' domain. Pain and poorer QoL were strongly associated, supporting construct validity. The SF-12 physical health component associated strongly with pain relief, and the mental health score with other facets, indicating good concurrent validity. Discriminant validity tests showed that PDM scores distinguished between ill and well patients, and between those reporting different health statuses. The PDM has fair to good psychometric properties indicating its value as a patient-reported outcome measure for clinical trials.