NEW DELHI: It's a well-known paradox that had little evidence to support it, until now. Doctors from UCLA's David Geffen School of Medicine have, for the first time, successfully demonstrated that obese patients actually fare better and have better chances of survival when hospitalised for acute heart failure than their leaner counterparts.

In the first-ever large scale study to assess the relationship between Body Mass Index and survival in patients hospitalised with acute heart failure, doctors have found the obesity paradox - BMI being inversely associated with long-term mortality in chronic heart failure - to be real.

The study has found that by weight category, in-hospital mortality rate was 6.3% for underweight, 4.6% for healthy weight, 3.4% for overweight and 2.4% for obese patients.

Researchers also found that for every five-unit increase in body mass, the odds of risk-adjusted mortality fell 10%, irrespective of the patients age, sex, blood urea nitrogen, blood pressure and additional prognostic factors.

Speaking to TOI, Gregg Fonarow, the school's director and lead author of this study, said, "The study suggests overweight, obese patients may have a greater metabolic reserve to call upon during an acute heart failure, which may lessen in-hospital mortality risk. Prior studies in outpatients with chronic heart failure had shown overweight patients had better chances of survival compared to patients who were normal weight, the so called obesity paradox."

Fonarow said the study was initiated in October 2001 and involved 263 hospitals in the US. Researchers utilised data of over 100,000 patients with acute heart failure patients from the Acute Decompensated Heart Failure National Registry from October 2001 through December 2004.

"Further study is required but the finding suggests that nutritional/metabolic support may have therapeutic benefit in specific patients hospitalised with heart failure. Obesity is a known risk factor for developing heart disease and heart failure and every effort should be made to avoid it, but once heart failure has manifested, this paradox seems to occur," Fonarow added.

According to cardiologist Dr K K Agarwal of Moolchand Hospital, obesity paradox is also called reverse epidemiology. "Such a paradox has been found in obese patients undergoing dialysis or suffering from advanced cancer and renal failure. Elderly patients who have better BMI have better chance of pulling through such severe health complications."