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

Abstract

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 χ² 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 χ² test revealed a statistically significant difference, with the acupuncture group demonstrating a markedly higher response rate than the sham group (82.91% vs51.79%, χ² = 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%) (χ² = 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 (χ²= 6.303, P =0.043). A significant difference was observed only between the low and high BMI groups (χ² = 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 (χ² = 4.571, P =0.033; χ² = 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.