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 χ 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 χ 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%, χ 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%) (χ 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 (χ 2 = 6.303, P = 0.043). A significant difference was observed only between the low and high BMI groups (χ 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 (χ 2 = 4.571, P = 0.033; χ 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.