What is reverse epidemiology in relation to obesity and mortality in patients with HF?
Reverse epidemiology is a phenomenon in which an exposure that is typically associated with an increased risk of disease is associated with a decreased risk or improved prognosis in a particular population. In relation to obesity and mortality in patients with HF, it has been observed that increased mortality is observed in patients with a BMI <18.5, while overweight and obese patients may have lower mortality than lean patients. This is thought to be due to potential differences in clearance of active natriuretic peptides, decreased levels of lipoprotein molecules and adipocytes, increased protection against endotoxin or inflammatory cytokines, and increased nutritional and metabolic reserve. However, brain natriuretic peptide levels still predict worse symptoms, impaired hemodynamics, and higher mortality in any BMI category, even in obese patients.