Body mass index and mortality in chronic obstructive pulmonary disease: a meta-analysis

• Published in: PloS one 2012-08, Vol.7 (8), p.e43892-e43892
• Main Authors: Cao, Chao, Wang, Ran, Wang, Jianmiao, Bunjhoo, Hansvin, Xu, Yongjian, Xiong, Weining
• Format: Article
• Language: English
• Subjects: Analysis; Biology; Body mass; Body Mass Index; Body size; Body Weight; China; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Clinical trials; Complications and side effects; Confidence intervals; Health aspects; Hospitals; Humans; Lung diseases; Medical prognosis; Medicine; Meta-analysis; Mortality; Obesity; Obesity - complications; Obesity - mortality; Obstructive lung disease; Overweight; Overweight - complications; Overweight - mortality; Patients; Population; Prognosis; Pulmonary Disease, Chronic Obstructive - complications; Pulmonary Disease, Chronic Obstructive - mortality; Risk analysis; Risk assessment; Science; Statistical analysis; Studies; Systematic review; Thinness - complications; Thinness - mortality; Underweight
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0043892

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.