PHILADELPHIA — The “obesity paradox” — the survival advantage of people with a higher body mass index (BMI) seen in some studies of myocardial infarction, heart failure, and other acute illnesses — may also apply to stroke, an analysis of patients in the FAST-MAG stroke trial showed.
Elevated BMI was associated with reduced 3-month mortality and reduced disability, reported Zuolu Liu, MD, of the University of California, Los Angeles, and co-authors, in an early-release abstract from the American Academy of Neurology meeting to be held here in May.
The findings mirrored those seen 6 years ago in Europe when BMI data from the TEMPiS trial were analyzed. “We pretty much showed exactly the same thing,” said Wolfram Doehner, MD, PhD, of Charite Universitatsmedizin Berlin in Germany.
“It’s counterintuitive, many people say. We have been told that being overweight is bad and that we should fight obesity and overweight by whatever means,” Doehner said in an interview with MedPage Today. “But it’s a little more complicated than that, because when patients do have a disease, being overweight seems to change the development of the disease.”
Other studies, however, have not linked obesity to better stroke outcomes, observed Tom Skyhoj Olsen, MD, PhD, of Bispebjerg University Hospital in Copenhagen.
In an analysis of 71,617 patients in Denmark, “we found no evidence of survival advantage linked to obesity,” Olsen told MedPage Today, and no significant difference in risk of death by stroke when normal weight (reference), overweight (HR 0.96), and obese (HR 1.0) stroke patients were compared.
“Stroke occurred 3 years earlier in overweight patients and 6 years earlier in obese patients than in normal weight,” he added.
In the current research, Liu and colleagues analyzed all acute ischemic stroke patients enrolled in the multicenter FAST-MAG study, looking at death, disability, or death defined by the modified Rankin Scale, and low stroke-related quality of life as defined on the Stroke Impact Scale.
The 1,033 patients in the FAST-MAG study had a mean age of 71, a mean NIH Stroke Scale Score of 10.6, and a mean BMI of 27.5. Less than half (45.1%) were female.
Risk of death declined linearly with higher BMI. Adjusted odds ratios for mortality declined across the BMI categories of underweight (OR 1.67), normal (reference), overweight (OR 0.85), obese (OR 0.54), and severely obese (OR 0.62).
Odds ratios for disability or death declined through the first four BMI categories — underweight (OR 1.19), normal (reference), overweight (OR 0.78), obese (OR 0.72) — but not for people who were severely obese (OR 0.96). Similar but non-significant trends were seen for low stroke-related quality of life.
How extra body fat may confer an advantage is unknown, but “one possible explanation is that people who are overweight or obese may have a nutritional reserve that may help them survive during prolonged illness,” Liu speculated.
A limitation of the study was that all participants were from southern California and results may not be similar in other places, Liu added. However, the racial and ethnic distribution of the population in this analysis mirrored that of the national population, she said.
Disclosures were not reported.