To the Editor:
The article written by Zamora et al1 provided an excellent description of the phenomenon known as the obesity paradox in heart failure patients, in this case in a population of heart failure outpatients who had received adequate concomitant treatment for heart failure.
Obstructive sleep apneahypopnea syndrome (OSAHS) is highly prevalent among the general population and is related to the development of various cardiovascular complications that determine patient prognosis, among them, ventricular dysfunction, systemic and pulmonary hypertension, cerebrovascular disease, and cardiac rhythm disorders.2-5 In addition, obesity is the main risk factor of OSAHS, with a direct relation observed between the degree of obesity and the severity of the sleep disorder. It has been estimated that as many as 40% to 90% of obese patients present OSAHS.6 Furthermore, OSAHS is very common in patients with heart failure, both those with left ventricular systolic dysfunction and those with normal systolic function.7 There is also evidence that OSAHS in subjects with heart failure is an additional independent predictor of mortality in this population.8
Zamora et al1 did not analyze the possibility of OSAHS in the patients of their series, something also not undertaken in various previous studies that have uncovered the phenomenon of the obesity paradox in heart failure.9 In view of the data discussed, it appears plausible to assume that OSAHS diagnosis and treatment in obese subjects with heart failure could widen the differences in mortality compared to nonobese subjects even further, something that would enhance the magnitude of the obesity paradox in heart failure. Evidently, future studies in this field will provide an answer to this hypothesis.