Obesity paradox in CKD
What is the obesity paradox in patients with CKD?
Obesity has reached epidemic proportions in the general population and has been linked to increased morbidity and mortality.
Several epidemiologic studies have suggested a link between obesity and higher risk of developing incident CKD; the link between obesity and adverse outcomes in the general population is evident from epidemiologic studies showing a linear increase in mortality associated with higher BMI, especially greater than 30 kg/m 2 .
Studies in patients with moderate to advanced CKD have shown a reversal of this risk factor pattern, with a linear decrease in mortality in those with higher BMI. In fact, patients with BMI levels reaching morbid obesity have shown the best survival, questioning the validity of the obesity paradigm in this patient population.
Similar reversals in risk factor patterns, also known as “obesity paradox” or “reverse epidemiology,” have emerged in other patient populations characterized by chronic disease states and a high burden of comorbid conditions (such as those with advanced chronic obstructive pulmonary disease, congestive heart failure, rheumatoid arthritis, malignancies, and liver cirrhosis).
The common thread in the populations displaying this phenomenon of reverse epidemiology is their extremely high short-term mortality rate, which probably explains the mechanism whereby obesity appears protective within short periods of time: in such patients the mechanisms responsible for the long-term deleterious effects seen in the general population (metabolic syndrome/insulin resistance/atherosclerosis) are likely overshadowed by the beneficial effects of higher overall nutritional reserves.
