ABSTRACT
Large-scale observational studies can provide useful information on changes in health outcomes over time. The aim of this study was to investigate the effect of 3 months of usual care on quality of life (QOL) and pain outcomes in noncancer chronic pain patients managed by pain specialists and to examine factors associated with changes in QOL. This was assessed using the EQ-5D and pain outcomes using the Brief Pain Inventory (BPI). Changes in QOL and pain were studied for the overall sample and in subgroups defined by baseline pain severity. Multivariate regression was used to investigate factors associated with change on EQ-5D. Three thousand and twenty-nine patients were included for analysis. After 3 months of usual care, a mean of 40.9% of patients showed improvement on individual EQ-5D dimensions, with the highest rates of improvement seen on the pain/discomfort (50.8%) and anxiety/depression (48.3%) dimensions. The EQ-5D Index increased from a mean (SD) of 0.35 (0.2) to 0.58 (0.21) points between baseline and month 3, and the thermometer from 41.5 (19.4) to 58.7 (17.8), indicating a large effect. Improvements in QOL were larger in those with severe baseline pain. The BPI severity summary score improved from a mean (SD) of 6.5 (1.4) to 4.1 (1.7) and the interference summary score from 6.6 (1.5) to 4.2 (1.9). Changes on the BPI severity and interference scores were associated with changes in the EQ-5D Index and thermometer. In conclusion, 3 months of usual care in noncancer pain patients led to substantial improvements in QOL and pain outcomes.