Effects of transcranial direct current stimulation on patient-reported outcomes in chronic low back pain: a systematic review and three-level meta-analysis

Abstract

Background Growing evidence suggests that central nervous system alterations may contribute to the persistence of chronic low back pain (CLBP). Transcranial direct current stimulation (tDCS) can effectively modulate cortical excitability and holds considerable potential for the rehabilitation of CLBP. However, evidence regarding its effects remains controversial. Purpose This study aimed to systematically evaluate the effects of tDCS on pain, disability, and psychosocial outcomes in individuals with CLBP. Methods Five electronic databases were searched from their inception to January 20, 2026. Randomized controlled trials were included to evaluate the effects of tDCS in CLBP individuals. Meta-analysis was performed using the random-effects model implemented in the metafor package in R. Subgroup analyses were based on tDCS polarity, electrode placement, current intensity, treatment sessions, and comparison type. Results A total of 14 randomized controlled trials were included. Meta-analysis results showed that compared with the control group, the tDCS group reported significantly reduced pain (standardized mean difference [SMD] = −0.40, 95% confidence interval [CI]: −0.61 to −0.19, P < 0.001) and disability (SMD = −0.18, 95 CI: −0.34 to −0.03, P < 0.02) in individuals with CLBP. However, no significant effects were observed for follow-up pain (SMD = −0.19, 95% CI: −0.46–0.08, P = 0.173), follow-up disability (SMD = −0.10, 95% CI: −0.26–0.05, P = 0.194), quality of life (SMD = 0.17, 95% CI: −0.08–0.41, P = 0.179), anxiety (SMD = −0.04, 95% CI: −0.23–0.15, P = 0.659), or depression (SMD = −0.18, 95% CI: −0.49–0.12, P = 0.241). Subgroup analyses based on tDCS polarity, electrode placement, current intensity, treatment sessions, and comparison type showed variations in effect estimates, but no significant between-subgroup differences were detected. Conclusion Current evidence suggests that tDCS may reduce pain and produce a small improvement in disability in individuals with CLBP. Given the low-to-moderate certainty of the available evidence, these findings should be interpreted cautiously. Systematic Review Registration identifier CRD420261286288.