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Public Health and Epidemiology - Respiratory Medicine

Body Mass Index and Mortality in Chronic Obstructive Pulmonary Disease: A Meta-Analysis
Published: Friday, August 24, 2012
Author: Chao Cao et al.

by Chao Cao, Ran Wang, Jianmiao Wang, Hansvin Bunjhoo, Yongjian Xu, Weining Xiong


The association between body mass index (BMI) and mortality in patients suffering from chronic obstructive pulmonary disease (COPD) has been a subject of interest for decades. However, the evidence is inadequate to draw robust conclusions because some studies were generally small or with a short follow-up.


We carried out a search in MEDLINE, Cochrane Central Register of Controlled Trials, and EMBASE database for relevant studies. Relative risks (RRs) with 95% confidence interval (CI) were calculated to assess the association between BMI and mortality in patients with COPD. In addition, a baseline risk-adjusted analysis was performed to investigate the strength of this association.


22 studies comprising 21,150 participants were included in this analysis. Compared with patients having a normal BMI, underweight individuals were associated with higher mortality (RR ?=?1.34, 95% CI ?=?1.01–1.78), whereas overweight (RR ?=?0.47, 95% CI ?=?0.33–0.68) and obese (RR ?=?0.59, 95% CI ?=?0.38–0.91) patients were associated with lower mortality. We further performed a baseline risk-adjusted analysis and obtained statistically similar results.


Our study showed that for patients with COPD being overweight or obese had a protective effect against mortality. However, the relationship between BMI and mortality in different classes of obesity needed further clarification in well-designed clinical studies.