Health-related quality of life and burden of disease in chronic pain measured with the 15D instrument.

Health-related quality of life (HRQoL) measurement aims to capture the complete, subjective health state of the patients and to comprehensively evaluate treatment outcomes. The aim of this study was to assess, using the 15D HRQoL instrument, HRQoL in a sample of 1528 chronic pain patients, referred to the multidisciplinary pain clinic of the Helsinki University Hospital during 2004 to 2012. The 15D results of the chronic pain patients were compared with those of a matched general population. To analyse the properties of the 15D, the results were compared with the preadmission questionnaire of the pain clinic, containing questions about background factors, aspects of the pain, and its impact on life. The mean 15D score of the chronic pain patients was one of the lowest reported using 15D; 0.710 vs 0.922 in the general population. It equalled the score of advanced cancer patients in palliative care. The 15D scores were normally distributed, and 15D showed both statistically and clinically significant discriminative power in pain-related background factors. Visual analogue scale on pain intensity, visual analogue scale on pain-related distress, and the impact of pain on daily life correlated well with the 15D score. Pain intensity did not have independent predictive value on the score. The results indicate heavy perceived burden of illness in chronic pain patients. In light of the questions analysed, 15D appears sensitive and discriminative in chronic pain patients in tertiary care. Instead of pain intensity, the impaired HRQoL in chronic pain was mainly because of the psychosocial aspects of pain.