Obese patients undergoing rehabilitation at an acute rehabilitation hospital recovered faster than patients of normal weight, according to a study by an Emory University researcher.
The findings, reported in the January 2008 issue of the American Journal of Physical Medicine & Rehabilitation, debunk previous assumptions that the obese or overweight have a slower recovery than do those who are normal weight.
"The study's findings are the opposite of what you might expect," says David T. Burke, MD, lead study author and chair of the Department of Rehabilitation Medicine in the Emory School of Medicine.
"After several analyses of the data, we continued to get the same results -- even across various diagnostic categories. We can't deny that this is a real phenomenon," Dr. Burke adds.
The study assessed the association of body mass index (BMI) with the functional independence measure (FIM) scores of 1,077 inpatients admitted to the medicine service of an acute rehabilitation hospital. FIM measures the ability of a person to mobilize and care for their basic needs after a severe injury or illness. The study also examined whether the association between patients' BMI and FIM was different across motor and cognitive skill categories.
Patients in the study were transferred to the rehabilitation hospital during the course of hospitalization for severe and complex medical issues including, renal/dialysis, infectious disease and other conditions.
The results showed that from the time of admission to the rehabilitation hospital to the time of discharge, median gains and the speed of the gains in FIM scores were highest among the most obese group (BMI of 30-35 or higher), followed by the obese group (BMI of 35-49). All obese patients progressed faster than did those who were in the normal weight category and those categorized as underweight. The findings held even after adjusting for age, gender and length of in-hospital stay.
"While this study shows us that obese patients can tolerate exercise and physical activity, and in fact recover more quickly than normal weight patients, it didn't answer the question of why this is the case," Dr. Burke says. "These findings surprised us all. We are currently engaged in studies that will help us understand these results."
The study article is titled "Association between body mass index and functional independence measure in patients with deconditioning." Dr. Burke served as the study's principal investigator and collaborated with Harvard Medical School researchers.