Predictors of long-term pain and disability in patients with low back pain investigated by magnetic resonance imaging: A longitudinal study Full Text
BMC Musculoskeletal Disorders, 11/02/2011
McNee P et al. – These findings suggest that the magnetic resonance imaging (MRI) abnormalities examined are not major predictors of outcome in patients with low back pain (LBP). They give no support to the use of MRI findings as a way of refining case definition for LBP in epidemiological research.Methods
- A consecutive series of patients aged 20–64 years, who were investigated by MRI because of mechanical LBP (median duration of current episode 16.2 months), were identified from three radiology departments, and those who agreed completed self–administered questionnaires at baseline and after a mean follow–up period of 18.5 months (a mean of 22.2 months from MRI investigation).
- MRI scans were assessed blind to other clinical information, according to a standardised protocol.
- Associations of baseline MRI findings with pain and disability at follow–up, adjusted for treatment and for other potentially confounding variables, were assessed by Poisson regression and summarised by prevalence ratios (PRs) with their 95% confidence intervals (CIs).
- Questionnaires were completed by 240 (74%) of the patients who had agreed to be followed up.
- Among these 111 men and 129 women, 175 (73%) reported LBP in the past four weeks, 89 (37%) frequent LBP, and 72 (30%) disabling LBP.
- In patients with initial disc degeneration there was an increased risk of frequent (PR 1.3, 95%CI 1.0–1.9) and disabling LBP (PR 1.7, 95%CI 1.1–2.5) at follow–up.
- No other associations were found between MRI abnormalities and subsequent outcome.