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Obesity associated with increased mortality in type 2 diabetes
Adults with type 2 diabetes and BMI 40 kg/m2 or greater faced a significantly increased mortality risk compared with less-severe overweight or with the general population, researchers in Sweden reported.
“While obesity is a major factor contributing to type 2 diabetes, reports on mortality outcomes associated with weight among people with type 2 diabetes are inconsistent,” Jon Edqvist, a PhD student at the Sahlgrenska Academy at the University of Gothenburg, and colleagues wrote. “An obesity paradox proposes that being overweight, as opposed to a low BMI, might be of benefit in type 2 diabetes, although more-recent reports indicate that any such association could be because of reverse causation or could be confounded by smoking.”
The researchers conducted a prospective study of patients in the Swedish National Diabetes Registry, all of whom had a diabetes duration of 5 years or less (n = 149, 345). Edqvist and colleagues assessed both long-term and short-term mortality in patients with type 2 diabetes and compared them with five matched controls from the general population per patient.
There were 17,546 deaths in patients with diabetes during a median follow-up of 5.5 years, the researchers reported. At death, mean age was 59.6 years; 40% of those who died were women. Among controls, there were 68,429 deaths from a population of 743,907.
BMI demonstrated a U-shaped relationship with mortality risk in the short term (within 5 years): the HR was 0.81 (95% CI, 0.75-0.88) for patients with BMI 30 kg/m2 to less than 35 kg/m2, and 1.37 (95% CI, 1.11-1.71) for those with BMI 40 kg/m2 or more, compared with controls.
All weight categories showed long-term mortality increases for patients with diabetes, the researchers reported. The nadir occurred at patients with BMI ranging from 25 kg/m2 to less than 30 kg/m2, and there was a stepwise increase leading to patients with BMI 40 kg/m2 or greater (HR = 2; 95% CI, 1.58-2.54). This increase was more pronounced in patients aged younger than 65 years, Edqvist and colleagues wrote.
“Our findings suggest that the apparent paradoxical findings in other studies in this area may have been affected by reverse causality and that weight management remains an important aspect of care in a large proportion of diabetes patients,” the researchers wrote. – by Andy Polhamus
Disclosures: Edqvist reports no relevant financial disclosures. One author reports grants from AstraZeneca; grants and personal fees from Boehringer Ingelheim; and personal fees from Eli Lilly, Janssen and Novo Nordisk, all outside of the submitted work.