Pulmonology · Medical Literature
Effectiveness of Metabolic and Bariatric Surgery for Patients with Obesity and Asthma: A Systematic Review and Meta-Analysis.
Abstract
Obesity is a modifiable risk factor for asthma worldwide and is associated with poor asthma control. Weight loss is an effective intervention for patients with obesity and asthma; however, a consistent association between metabolic bariatric surgery (MBS) and asthma in patients with obesity is lacking. To assess the effects of MBS in patients with obesity and asthma, we conducted a meta-analysis of data from inception to February 2026. Thirty-three observational studies including 3731 patients were analyzed. A total of 47% of patients achieved discontinuation of asthma medication (95% CI, 0.38-0.56; p < 0.05), and 58% of patients achieved clinical asthma remission (95% CI, 0.45-0.70; p < 0.05). Additionally, MBS was associated with an 8.5% increase in forced expiratory volume in one second (FEV1) (95% CI, 4.5-12.6; p < 0.05) and a 9.4% increase in forced vital capacity (FVC) (95% CI, 6.3-12.6; p < 0.05). This evidence suggests that MBS results in clinical remission of asthma and improvement in pulmonary function in patients with obesity and asthma. KEY POINTS: •MBS can alleviate clinical asthma in patients with obesity. •MBS can improve FEV1 in patients with obesity and asthma. •MBS can improve FVC in patients with obesity and asthma.
Clinical relevance
Does metabolic and bariatric surgery (MBS) improve asthma-related outcomes — including clinical remission, medication discontinuation, and pulmonary function — in patients with concurrent obesity and asthma? __SNAPSHOT__ {"studyDesign":"Systematic review and meta-analysis of observational studies (inception to February 2026)","setting":"Multicenter; international; institution type not reported. Lead author affiliated with Hospital Don Benito-Villanueva, Don Benito, Spain.","sampleSize":"n = 3,731 patients across 33 observational studies","population":"Adults with obesity and a concurrent diagnosis of asthma undergoing metabolic and bariatric surgery; predominance of female participants across included studies","intervention":"Metabolic and bariatric surgery (MBS; specific procedure types not uniformly reported across included studies)","comparator":"Not applicable — single-arm pre/post design within included observational studies; no surgical vs. non-surgical comparator arm reported in the meta-analysis","primaryOutcome":"Clinical asthma remission and discontinuation of asthma medication post-MBS; secondary outcomes included changes in FEV1 and FVC","followUp":"Variable across included studies; uniform follow-up duration not reported at the meta-analysis level","fundingSource":"No specific grants from public, commercial, or non-profit funding agencies received"}
Key findings
Among 3,731 patients across 33 observational studies, MBS was associated with asthma medication discontinuation in 47% of patients (95% CI: 0.38–0.56; p < 0.05) and clinical asthma remission in 58% of patients (95% CI: 0.45–0.70; p < 0.05). Pulmonary function improved significantly: FEV1 increased by a mean of 8.5% (95% CI: 4.5–12.6; p < 0.05) and FVC increased by a mean of 9.4% (95% CI: 6.3–12.6; p < 0.05). The wide confidence intervals for both remission (0.45–0.70) and medication discontinuation (0.38–0.56) indicate substantial between-study heterogeneity and statistical imprecision. Absolute effect sizes for FEV1 and FVC are reported as mean percentage point changes, not as changes in absolute liters or percent-predicted — limiting direct comparison to spirometric thresholds used in clinical practice. NNT cannot be calculated from the data as reported; no surgical complication rates, asthma exacerbation rates, or safety data were reported at the meta-analytic level.
Practice implications
This meta-analysis provides the most current pooled estimate — drawn from data through February 2026 — supporting the association between MBS and meaningful improvements in asthma outcomes, including clinical remission in approximately 58% and medication discontinuation in approximately 47% of patients with obesity-related asthma. These findings are statistically significant and directionally consistent with prior smaller reviews. However, several critical limitations constrain their clinical applicability: (1) all 33 included studies were observational, with no randomized controlled trials available, precluding causal inference; (2) 12 of 33 studies were rated as only fair quality due to methodological issues; (3) 28 of 33 studies included fewer than 50 patients, raising concerns about individual study power and publication bias; (4) female participants predominated across all studies, limiting generalizability to male patients; (5) no subgroup analyses were performed stratifying by asthma phenotype or endotype, severity, metabolic syndrome status, concurrent GERD, or smoking — all factors known to modify surgical response; and (6) only the abstract was available for this review, which constrains full assessment of heterogeneity statistics, funnel plot symmetry, and surgical procedure breakdown. The pulmonary function improvements (FEV1 +8.5%, FVC +9.4%) are physiologically plausible and consistent with relief of mechanical restriction from abdominal adiposity, but their clinical meaningfulness relative to a minimum clinically important difference threshold cannot be fully assessed from the data as reported. Clinicians should regard MBS as a potentially beneficial but not yet definitively proven intervention for obesity-asthma comorbidity, and individualize surgical candidacy based on standard MBS criteria rather than asthma outcomes alone. Patients with concurrent metabolic syndrome may derive attenuated benefit, per external evidence. __LIMITATIONS__ Exclusively observational evidence base; no RCTs exist in this area, precluding causal conclusions,12 of 33 studies rated as only fair quality due to methodological deficiencies,28 of 33 studies enrolled fewer than 50 patients, raising concerns about individual study reliability and publication bias toward positive results,Female predominance across all included studies limits generalizability to male patients,No subgroup analyses by asthma phenotype/endotype, asthma severity, metabolic syndrome status, GERD, or smoking status — all established effect modifiers,Heterogeneous definitions of 'clinical asthma remission' and 'medication discontinuation' likely across studies; specific definitions not detailed in the abstract,Specific MBS procedure types (Roux-en-Y gastric bypass vs. sleeve gastrectomy vs. adjustable gastric band) not reported or stratified in the pooled analysis,Variable and incompletely reported follow-up durations limit assessment of durability of benefit,Wide confidence intervals for remission (0.45–0.70) and medication discontinuation (0.38–0.56) reflect substantial statistical imprecision and likely high between-study heterogeneity,FEV1 and FVC reported as percentage change, not absolute liters or percent-predicted; comparison to minimum clinically important difference thresholds is limited,No surgical safety or complication data reported at the meta-analytic level,No comparison to non-surgical weight loss interventions; superior benefit over diet/exercise programs cannot be established from this analysis alone,Only the abstract was available for full critical appraisal __BOTTOM_LINE_CATEGORY__ promising_but_preliminary __BOTTOM_LINE__ This meta-analysis of 33 observational studies (n = 3,731) reports that metabolic and bariatric surgery is associated with clinical asthma remission in approximately 58% and asthma medication discontinuation in approximately 47% of patients with obesity and asthma, alongside statistically significant improvements in FEV1 and FVC. These findings are hypothesis-generating and directionally consistent with known obesity-asthma pathophysiology, but the exclusive reliance on small observational studies, absence of RCT data, female predominance, and lack of subgroup analysis by asthma severity or phenotype preclude definitive practice change. MBS should continue to be considered for eligible patients with obesity on its established metabolic and cardiovascular indications; asthma improvement may represent a meaningful secondary benefit, but should not yet serve as a primary or standalone indication for surgery.