Author(s): Brigham E.; Wise R.; Anderson J.A.; Brook R.D.; Calverley P.M.A.; Celli B.R.; Cowans N.J.; Diserens J.E.; Crim C.; Yates J.; Martinez F.J.; Newby D.E.; Vestbo J.
Source: American Journal of Respiratory and Critical Care Medicine; 2018; vol. 197
Publication Date: 2018
Publication Type(s): Conference Abstract
Available at American Journal of Respiratory and Critical Care Medicine – from Edge Hill Aintree LIRC (lib302411) Local Print Collection [location] : Edge Hill Aintree LIRC.
Abstract:RATIONALE While in the general population obesity confers a higher risk of mortality, several studies in COPD populations demonstrate improved survival in obese compared with normal weight individuals; the “obesity paradox.” Few studies evaluating the obesity paradox include individuals at the extreme of obesity (BMI >=40 kg/m2). We utilized data from the SUMMIT Trial (a double-blind randomized controlled trial of fluticasone furoate and vilanterol in adults with moderate COPD and heightened cardiovascular risk) to post hoc investigate consistency of the paradox across the full range of BMI. METHODS BMI was categorized as follows: underweight <20 kg/m2; normal 20-<25 kg/m2; overweight 25-<30 kg/m2; class I obesity 30-<35 kg/m2; class II obesity 35-<40 kg/m2; class III obesity >=40 kg/m2. The effect of BMI on time to death was modeled via a proportional hazards model, with normal weight as the reference group, and adjusted for the following confounders: age, sex, region, race, ischemic heart disease, vascular disease, smoking status, cardiovascular history and risk by age, previous COPD exacerbations, percent predicted FEV1, treatment arm, BMI, and a treatment arm by BMI interaction term. RESULTS 16,485 men and women from 43 countries with FEV1/FVC <0.7, FEV1 50-70% predicted and at least 10 pack-years smoking history were in the SUMMIT trial. Complete baseline characteristics of trial participants were published previously. No treatment arm by BMI interaction was present, therefore all treatment arms are presented together. Relative to the normal weight group, underweight individuals demonstrated increased mortality (HR 1.31 (95% CI 1.04-1.64). Reduced mortality was noted in overweight (HR 0.62 (95% CI 0.52-0.73)) and obese class I (HR 0.75 (95% CI 0.62-0.90)) groups. In obese class II there was also a trend for reduced mortality (HR 0.85 (95% CI 0.66-1.10)); however, there was increased mortality compared with normal weight in obese class III (HR 1.36 (95% CI 1.00-1.86)) (Figure 1). CONCLUSION Within a large, multinational cohort of patients with moderate COPD and increased cardiovascular risk, the phenomenon of reduced mortality with obesity did not hold true at BMI >=40 kg/m2. These results challenge the obesity paradox in moderately obstructed patients with cardiovascular risk, suggesting that obesity may not remain protective at the extremes in this population. (Figure pressented).