[Chronicity, recurrence, and return to work in low back pain: common prognostic factors]

To determine the common risk factors of recurrence, chronicity and non return to work in low back pain.

A systematic review of the literature was done by searches of Medline, Embase, Pascal, the Cochrane database and also in the unindexed literature. Keywords used were low back pain, chronic, risk factors, recurrence, predictive value of tests, prognosis, confounding factors. Studies were assessed by two readers using the ANAES (French Agency for Health Assessment) scale allowing classification into high-, moderate- and low-quality trials. The scientific evidence level of the identified risk factors depend on the methodological quality of the studies, the number of studies in agreement, the coherence of their results and their clinical relevance.

Fifty-four high quality studies were included. Several prognostic factors are common to the three described clinical situations. A history of low back pain (including the concept of pain severity, duration, disability, leg pain, related sickness leave and a history of spinal surgery), low level of job satisfaction and poor general health are highlighted with a strong level of evidence. Socioprofessionel and psychological factors including employment status, amount of wage, workers' compensation, and depression were found but with moderate level of evidence. Physical factors including lifting time per day and work postures were also found with moderate level of evidence.

This study confirm that several prognostic factors are commun to recurrence, chronicity and non return to work in low back pain. Early identification of these factors is important in understanding, and hopefully preventing, the recurrence or the progression to chronicity and disability in low back trouble.