Transcutaneous Electrical Nerve Stimulation (TENS) for Opioid-Induced Constipation in Palliative Care: A Systematic Review and Network Meta-Analysis

BACKGROUND: Opioid-induced constipation (OIC) has become increasingly prevalent with the rise of prescription opioid use, particularly in patients with advanced illnesses. Existing literature suggests that transcutaneous electrical nerve stimulation (TENS) could be applied to treat cancer pain and reduce OIC incidence. However, there need to be more systematic review studies on the effectiveness of TENS in treating OIC. OBJECTIVE: In order to fill the gap of TENS in treating OIC in current knowledge, we have conducted a systematic review and network meta-analysis. METHODS: The comprehensive computer retrieval PubMed, Embase, Cochrane, China National Knowledge Infrastructure (CNKI), Chinese Biomedical (CBM), and Wanfang Database were used to collect literature for relevant studies of TENS treatment of OIC, in accordance with the standard of literature filtering, data extraction, and quality evaluation. The data were meta-analysed using ReviewManager 5.3 software recommended by Cochrane. RESULTS: A total of 180 pieces of literature were yielded through original search. Based on the inclusion and exclusion criteria, a total of 9 articles were included in this study. Our analysis of seven studies has revealed that TENS (28.18%) significantly reduces the incidence rate of OIC compared to control (52.45%) (I(2) = 57%, P=0.03; OR = 0.66 (95% CI, 0.53 to 0.82), Z = 3.70, P < 0.01). The results of two studies indicated that TENS significantly improved the quality of life compared to the control group (i.e., treatment-as-usual only) (I(2) = 80%, P=0.03; OR = −1.91; 95% CI, −2.54 to −1.29, Z = 6.00, P < 0.01). CONCLUSION: The administration of TENS therapy holds the potential to mitigate the occurrence of OIC and augment the quality of life for individuals suffering from cancer. Particularly, TENS therapy proves to be appropriate for propagation within community and domestic environments. Nevertheless, advanced clinical randomized controlled trials of superior quality are necessary to authenticate the comprehensive clinical efficiency and safety of this therapy. Further investigation is indispensable to comprehend its mechanism in greater detail and establish the optimum therapeutic strategy.