Diabetes, Not Obesity, Increases Critical Illness and Death Risk

LEXINGTON, Ky. Sept. 25 -- Diabetes is a strong predictor of acute organ failure and early death for obese or non-obese patients alike, eclipsing even obesity without diabetes, according to researchers here.

In the absence of diabetes, a patient's body mass index (BMI) did not foretell organ failure or in-hospital death, according to a large prospective cohort study of 15,408 middle-aged adults, reported in the Sept 25 issue of Critical Care.

By contrast, diabetics had a threefold higher rate of organ failure over three years from baseline versus non-diabetics, said David Mannino, M.D., of the University of Kentucky here, and colleagues here and at Emory in Atlanta. Within three years, 5.4% of those with diabetes died, compared with 1.6% of those without diabetes.

Patients in the analysis, ages 44 to 66, came from the Atherosclerosis Risk in Communities study and had originally been studied from 1986 to 1989. Overall, 11.9% of all the participants had diabetes, and not surprisingly those with diabetes were more likely than those without diabetes to have a BMI of 30 or more (52% vs 24% P

Discussing the limitations of the study, Dr. Mannino and colleagues listed a number of shortcomings, including the possibility that the diagnostic codes used to identify specific medical conditions may have underestimated their true prevalence. Also, they said, the fact that they focused on hospitalized patients, left the possibility that there may have been organ failure and deaths without hospitalization.

In addition, they said, they did not subcategorize morbidly obese patients (BMI > 40), a small group of patients who should be studied separately.

Treatment for diabetes and acute organ failure may have changed since the late 1980s when patients were enrolled in this trial. It is also possible, they noted, that the definition of diabetes might not have included all subjects with the disease.

Finally, they wrote that because of the relatively short three-year follow-up, over the long term patients with high BMIs might be more likely to develop diabetes with its life-threatening risks.

The results of this large prospective study of middle-aged U.S. adults suggest that the development of acute organ failure followed by death is related more to the presence of diabetes than to an increased BMI, the researchers said in summary.

These results, they added, "bring a new perspective on this still controversial subject of obesity, critical illness, and mortality."

The findings "call for further investigation to determine the mechanisms that underlie this complex relationship between obesity, diabetes, and critical illness," Dr. Mannino concluded.