Impact of Body Mass Index on Risk of Exacerbation in Patients With COPD: A Systematic Review and Meta-Analysis.

Objective: To synthesize current evidence of the association between body mass index (BMI) categories and the risk of exacerbation in patients with chronic obstructive pulmonary disease (COPD).

Methods: A systematic search was conducted across three electronic databases: PubMed, Embase, and Scopus. Eligible studies should have reported on the association between BMI (either as continuous or categorical) and a risk of COPD exacerbation, as defined according to recognized clinical criteria. Observational studies (cohort, case-control, cross-sectional) were eligible for inclusion. The Newcastle Ottawa Scale (NOS) was used to evaluate the methodological quality. Combined effect sizes were reported as relative risk (RR) and corresponding 95% confidence intervals (CI).

Results: A total of 11 studies were included. Of them, four studies were prospective, and four were retrospective cohorts in design, two were cross-sectional studies and one study was a secondary data analysis from a randomized trial. Compared to patients with normal BMI, underweight patients had increased risk of COPD exacerbation (RR 1.90, 95% CI: 1.03, 3.48; N=7, I²=94.2%). Overweight and obese BMI status was associated with a similar risk of exacerbation.

Conclusion: Our findings report that underweight, but not overweight or obese patients, have increased risk of COPD exacerbation, compared to individuals with normal BMI. This differential association emphasizes the need for nuanced investigations into the underlying mechanisms of the impact of BMI on the course of COPD. Further research is needed to inform personalized interventions and improved COPD management strategies.