Impact of body mass index on the efficacy of acupuncture treatment of postprandial distress syndrome: secondary analysis of a randomized clinical trial

OBJECTIVE: To assess the impact of body mass index (BMI) on the effectiveness of acupuncture in treating postprandial distress syndrome (PDS).METHODS: Data from 278 patients enrolled in a prior multicenter, randomized, sham-controlled trial were analyzed in this secondary study.Patients were classified into three groups according to baseline BMI: low, normal, and high.The primary outcome was the response rate after 4 weeks of treatment.The 2 test was used to examine the effect of BMI on acupuncture efficacy.After multiple imputation for missing data, logistic regression analysis was performed to evaluate this association.A sensitivity analysis was conducted by combining the low and normal BMI groups.In addition, BMI was analyzed as a continuous variable using logistic regression to explore its relationship with treatment efficacy in the acupuncture group. RESULTS:The 2 test revealed a statistically significant difference, with the acupuncture group demonstrating a markedly higher response rate than the sham group (82.91% vs 51.79%, 2 = 25.34,P < 0.001).In both the normal and high BMI categories, the response rate in the acupuncture group (82.91%) was higher than that in the sham acupuncture group (48.21%) ( 2 = 25.34,P < 0.001).Following multiple imputation, logistic regression analysis demonstrated a significant overall association between BMI category and treatment response (P < 0.001).Acupuncture showed superior efficacy compared with sham acupuncture [OR = 1.97, 95% CI (1.34, 2.90), P < 0.001].At week 4, response rates were 68.4% in the low BMI group, 81.7% in the normal BMI group, and 96.3% in the high BMI group ( 2 = 6.303,P = 0.043).A significant difference was observed only between the low and high BMI groups ( 2 = 6.717,P = 0.010).Sensitivity analysis showed that the high BMI group achieved significantly better outcomes than the non-high BMI group in elimination rates at week 8 and week 12 ( 2 = 4.571, P = 0.033; 2 = 4.589, P = 0.032).Logistic regression analysis indicated that BMI was an independent predictor of response rate at week 4 [OR = 1.186, 95% CI (1.010, 1.394), P = 0.038] and elimination rate at week 12 [OR = 1.126, 95% CI (1.002, 1.265), P = 0.047], whereas no significant associations were observed at other follow-up points.CONCLUSION: This subgroup analysis indicated that acupuncture improved PDS symptoms across different BMI categories.Acupuncture was suggested as a viable therapeutic option for patients with PDS, particularly those with a higher BMI.