Findings from a new study suggest that obesity per se is not a risk factor for acute organ failure or death. However, diabetes, which often develops in obese individuals, does increase the risk. Study co-author Dr. David M. Mannino, from the University of Kentucky Medical Center in Lexington stated that, "There are several studies out there showing worse outcomes for people with higher BMIs. "Surprisingly, most of the studies really didn’t look at how diabetes entered into the picture."
The present research, which is reported in the September 24th issue of Critical Care, involved an analysis of data from 15,408 subjects who participated in the Atherosclerosis Risk in Communities (ARIC) study, a prospective, population-based study.
BMI and the presence of diabetes were determined at baseline. A subject was considered diabetic if they confirmed that a doctor told them they had diabetes, if they reported recently taking medications for "diabetes or high blood sugar," or if their fasting blood glucose was 126 mg/dL or higher.
The main outcomes were the development of acute organ failure within 3 years of the baseline evaluation, in-hospital death during organ failure, and death at 3 years in all subjects and in those with organ failure.
Consistent with previous research, the risk of diabetes was higher in obese subjects. The rate of diabetes among subjects with a BMI of at least 30 was 22.4%, significantly higher the 7.9% rate noted among subjects with a lower BMI.
As noted, BMI alone had no bearing on the risk of acute organ failure. Diabetes, by contrast, was associated with an increased rate of organ failure, at 2.4% versus 0.7% in nondiabetics (p < 0.01).
Diabetes was also associated with an elevated risk of death among organ failure patients compared with nondiabetic patients, while hospitalized (46.5% vs. 12.2%) and at 3 years (51.2% vs. 21.1%).
Given the association between a high BMI and diabetes, obese people are still at elevated risk, albeit indirectly, for developing the adverse outcomes described in the present study, Dr. Mannino noted.
Moreover, due to low subject numbers, "we could not address the effect of morbid obesity," so it is possible that a very high BMI is, in fact, an independent risk factor for organ failure and death, he added.
Slynkova, K, et al "The role of body mass index and diabetes in the development of acute organ failure and subsequent mortality in an observational cohort" Critical Care 2006; 9/25.