Transcutaneous electrical nerve stimulation over acupoint for chronic obstructive pulmonary disease: A systematic review and meta-analysis

BACKGROUND: Transcutaneous electrical nerve stimulation over an acupoint (acu-TENS), a new technique applied in pulmonary rehabilitation programs, has been gradually used in the management of chronic obstructive pulmonary disease (COPD). However, the effects of acu-TENS have not been fully evaluated. Therefore, this review was conducted to assess the effects of acu-TENS on COPD. METHODS: A total of seven electronic databases were searched from their inception to September 2021 for randomized controlled trials of acu-TENS for COPD. Two investigators independently performed data extraction and methodological quality assessment. Heterogeneity was examined by Cochrane χ(2) and I(2) tests. The source of heterogeneity was investigated by subgroup analysis or sensitivity analysis. RESULTS: In our review, ten studies between 2008 and 2021 were included. The aggregated results indicated that acu-TENS showed positive effects in forced expiratory volume in 1 s (FEV1) [MD = 0.13 L, 95% CI (0.11–0.16), P < 0.00001], FEV1% predicted [MD = 5.92%, 95% CI (3.43–8.41), P < 0.00001], 6-min walk distance (6MWD) [MD = 14.68m, 95% CI (6.92–22.44), P = 0.0002], dyspnea visual analog scale (DVAS) [MD = −7.58, 95%CI (−14.33 to −0.84), P = 0.03], modified Borg scale (MBS) [MD = −0.46, 95% CI (−0.86 to −0.06), P = 0.03], and COPD assessment test (CAT) [MD = −4.25, 95% CI (−5.24 to −3.27), P < 0.00001]. Although six studies reported adverse effects, only one patient had shoulder pain after acu-TENS. CONCLUSION: Acu-TENS seems to be effective in improving pulmonary function and health status in patients with COPD, with little effect on exercise capacity and dyspnea. However, this result should be interpreted with caution, and high-quality RCTs were needed for further verification.