To investigate the contribution of symptoms of depression to future episodes of low back pain (LBP).
A search was conducted of AMED, CINAHL, Embase, Health and Society (H&S), LILACS, MEDLINE, PsycINFO, Scopus, and Web of Science databases. We included cohort studies investigating the effect of symptoms of depression on the development of new episodes of LBP, either lifetime incidence or a recurrent episode, in a population free of LBP at baseline. We accepted the original study's definition for a new episode of LBP, and for classifying patients as LBP-free at study entry. Two independent investigators extracted data and assessed methodological quality. Meta-analyses with random effects were used to pool risk estimates.
We included 19 studies, with 11 incorporated in the meta-analyses. Overall pooled results showed that symptoms of depression increased the risk of developing LBP (odds ratio [OR] 1.59, 95% confidence interval [95% CI] 1.26-2.01). The risk was similar in studies that used the diagnostic interview method (OR 1.66, 95% CI 1.14-2.42) and in studies using self-report screening questionnaires (OR 1.68, 95% CI 1.05-2.70). No statistically significant relationship was observed when we pooled studies that employed nonspecific screening questionnaires (OR 1.17, 95% CI 0.48-2.87). Three studies provided results in incremental categories of symptoms of depression and the pooled OR for the most severe level of depression (OR 2.51, 95% CI 1.58-3.99) was higher than for the lowest level (OR 1.51, 95% CI 0.89-2.56).
Individuals with symptoms of depression have an increased risk of developing an episode of LBP in the future, with the risk being higher in patients with more severe levels of depression.