Auricular stimulation for preoperative anxiety - a systematic review and meta-analysis of randomized controlled clinical trials
Abstract Study objective: Previous randomized controlled trials (RCTs) suggest that auricular stimulation (AS) is safe and effective in treatment of preoperative anxiety; however, a systematic evaluation is lacking. The aim was to summarize the evidence on efficacy and safety of AS in the treatment of preoperative anxiety and evaluate the quality of evidence. Design: MEDLINE (PubMed), EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), ISI Web of Science, and Scopus Database were searched from their inception to June 2020. Interventions: RCTs were included according to pre-defined criteria including AS used for preoperative anxiolysis, compared to various control procedures and measured with validated anxiety questionnaires. Measurements: Quality and risk assessment of included trials was performed using the Cochrane 6.2, 2021 handbook criteria and meta-analysis of symptom score data was conducted using the software RevMan V.5.3. Main results: Fifteen trials with total 1603 patients were included in the review. AS was superior to sham control (7 trials; low certainty): Standardized Mean Difference (SMD) = -0.58, 95% confidence interval (CI) -0.87 to -0.29, p<0.0001; better than no intervention (4 trials; very low certainty): SMD = -1.01, 95% CI (-1.58 to -0.45), p=0.0004; and comparable with anxiolytic effect of benzodiazepines (3 trials; very low certainty): SMD = -0.03, 95% CI (-0.34 to 0.28), p=0.84. AS was safe, the overall quality of evidence was low or very low. Conclusions: Auricular stimulation may be useful in treatment of preoperative anxiety. Due to low certainty in effect estimates, large trials with appropriate methodology are needed to confirm the benefit of this therapeutic option.