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

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.

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.

Weight loss reduced ACQ score (WMD -0.67 [95%CIs - 1.20, -0.13], P = 0.02; I² 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; I² 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; I² 95.6%, P < 0.001) and forced vital capacity percent predicted (FVC _pp, WMD 4.90 [-3.22, 13.02], P = 0.24; I² 91.4%, P < 0.001) were not statistically significant.

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.