Challenging the obesity paradox: extreme obesity and COPD mortality in the SUMMIT trial

Populations with COPD demonstrate higher survival in overweight and obese compared with normal weight; the "obesity paradox". Relationships in less-severe COPD are unclear, as is the impact of cardiovascular risk, and few studies include individuals at extremes of obesity. We examined the relationship between body mass index (BMI; defined as underweight: <20 kg·m-2, normal: 20-25 kg·m-2, overweight: 25- <30 kg·m-2, obese class I: 30- <35 kg·m-2,...