A Cochrane review included 6 studies with a total of 2 316 subjects. A total of 2 061 participants with no back pain were included in three trials, which tested both customized and non-customized insoles versus no intervention or sham-inserts for the prevention of back pain in military settings. The trials lasted five to fourteen weeks. The pooled RR in favor of the use of insoles was 0.73 (95% CI 0.43 to 1.22, P = 0.17). Three studies included mixed participant populations (and thus had both a prevention and treatment assessment). Their data suggest that insoles may help decrease low-back pain prevalence and magnitude, but drawbacks in design and data presentation call into question these conclusions. No pure treatment trials were found.
Comment: The quality of evidence is downgraded by inconsistency (heterogeneity in interventions and outcomes) and by study quality (more than 20% loss to follow up).