Prognostic factors for short-term improvement in acute and persistent musculoskeletal pain consulters in primary care

BACKGROUND Given the costs associated with the management of musculoskeletal pain in primary care, predicting the course of these conditions remains a research priority. Much of the research into prognostic indicators however considers musculoskeletal conditions in terms of single pain sites whereas in reality, many patients present with pain in more than one site. The aim of this study was to identify prognostic factors for early improvement in primary care consulters with acute and persistent musculoskeletal conditions across a range of pain sites. METHODS Consecutive patients with a new episode of musculoskeletal pain completed self-report questionnaires at baseline, and then again at the 4/5th treatment visit, and if they were still consulting, at the 10th visit. The outcome was defined as patient self-report improvement sufficient to make a meaningful difference. Independent predictors of outcome were identified using multivariate regression analyses. RESULTS Acute (<7 weeks) patients, on average, had more severe conditions in terms of pain, disability, anxiety and work fear-avoidance behaviour than patients with persistent (≥7 weeks) pain, but were more likely to be better by the 4/5th visit. Several variables at baseline were associated with improvement at the 4/5th visit, but the predictive models were weak and unable to discriminate between patients who were improved and those who were not. In contrast, it was possible to elicit a predictive model for improvement later on at the 10th visit, but only in patients with persistent pain. Being employed, reporting a decline in work fear-avoidance behaviour at the 4/5th visit, and being better by the 4/5th visit, were all independently associated with improvement. This model accounted for 34.3% (p < 0.001) of the variation in observed improvement, and had good discriminative ability (the area under receiver operating characteristic (ROC) curve was 0.80 (95%CI 0.73 to 0.86)) and approximate balance in correctly identifying improved and non-improved cases (79.0% and 68% respectively). CONCLUSIONS We were unable to identify baseline characteristics that predicted early outcome in musculoskeletal pain patients. However, early self-reported improvement and decline in work fear-avoidance behaviour as predictors of later improvement highlighted the importance of speedy recovery in persistent musculoskeletal pain consulters. Our findings reinforce the elusive nature of baseline predictors, and the need for more emphasis on early changes as prognostic predictors in musculoskeletal conditions.