Generic prognostic factors for musculoskeletal pain in primary care: a systematic review.

Problem

Whilst evidence is available for prognostic factors for individual musculoskeletal (MSK) conditions, little is known about generic prognostic factors across a range of MSK conditions, regardless of anatomical site. The aim of this study is to review and synthesise evidence for generic prognostic factors for MSK pain in primary care setting.

Approach

MEDLINE, CINAHL, PsychINFO, and EMBASE were searched for prospective cohort studies, based in primary care. Studies were included if they reported on adults consulting with MSK pain and provided data on a measure of association between baseline characteristics (prognostic factors) and outcome (search period – inception to December 2015). A prognostic factor was identified as generic when found to be significantly associated with any outcome for two or more different MSK pain complaints. Analysis focused on consistency (consistent if ≥75% of studies reporting on the factor showed the same direction of association with outcome) and study quality (each study was assessed against 15 items of internal and external validity and a total score of 9 points or more considered high quality).

Findings

14682 independent citations were identified and 78 studies were included (more than 48000 participants with 18 different outcome domains). 51 studies were on spinal pain/back pain/low back pain, 12 on neck/shoulder/arm pain, 3 on knee pain, 3 on hip pain and 9 on multisite pain/widespread pain. Total quality scores ranged from 5 to 14 (mean 11) and 65 studies (83%) scored 9 or more. Out of a total of 78 different prognostic factors for which data were provided, 15 factors were considered as generic with strong evidence for: widespread pain, high functional disability and somatisation. Evidence was moderate for high pain intensity, long pain duration and high depression/anxiety score. Evidence that factors are not generic was strong for low level of education and moderate for use of pain medications. Evidence was not conclusive for poor social support and heavy lifting. Sensitivity analysis using different cut-off levels for quality scores did not change the overall direction of evidence.

Consequences

This large review of studies, the majority of which were of high quality, provides important new evidence about generic prognostic factors for musculoskeletal pain in primary care. Identifying factors that apply to any MSK pain is important to investigate whether targeting these factors or identifying patients at risk or poor prognosis across conditions would help improve patient outcomes. It could also help focus the discussion between clinicians and their patients in primary care, where most these conditions are managed.