Weight loss and asthma control: A systematic review of randomized controlled trials

Summary Background In the current systematic review and meta‐analysis, we evaluated the possible role of weight loss on asthma control, quality of life (QOL), and clinical outcomes among patients with asthma. Methods We performed a systematic search of PubMed, CINAHL, and OVID Medline for randomized controlled human trials that examined the effects of weight loss on asthma control, QOL, and spirometry results, from 1 January 2000 to 31 December 2023. Twelve eligible studies (total n = 1052 participants) were included. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were used to evaluate the effect size. Subgroup analyses and meta‐regression approaches were performed to reveal possible sources of heterogeneity. Fractional polynomial modeling was performed to assess non‐linear associations. Results Weight loss reduced ACQ score (WMD −0.67 [95%CIs − 1.20, −0.13], P = 0.02; I 2 91.3%, P < 0.001), and improved forced expiratory volume percent predicted (FEV)1 pp (WMD 13.08 [95%CIs 2.42, 23.73], P = 0.02; I 2 94.1%, P < 0.001) among patients with asthma. In a dose–response analysis, a significant non‐linear association was reported between change in weight and changes in FEV1 pp (P non‐linearity = 0.01). The effects of weight loss on QOL (WMD 0.53 [−0.38, 1.44], P = 0.25; I 2 95.6%, P < 0.001) and forced vital capacity percent predicted (FVC pp , WMD 4.90 [−3.22, 13.02], P = 0.24; I 2 91.4%, P < 0.001) were not statistically significant. Conclusion Weight loss improves asthma control and FEV1 pp among patients with asthma in a two‐class meta‐analysis. Because of the relatively low number of well‐designed clinical trials (n = 12), further trials are needed to better define the beneficial effects of weight loss on asthma control.