Patients who develop diabetes at a normal weight may be at higher risk for mortality compared with those who are overweight or obese at diagnosis, according to data from a pooled longitudinal analysis of five cohort studies.

The study included 2,625 patients (aged >40 years, 50% women) from the Atherosclerosis Risk in Communities (ARIC) study, Cardiovascular Health Study (CHS), Coronary Artery Risk Development in Young Adults (CARDIA) study, Framingham Offspring Study (FOS), and the Multi-Ethnic Study of Atherosclerosis (MESA) who developed incident diabetes.

Researchers chose the studies based on repeated measures of body weight, fasting glucose level and medication use. Other factors included demographic characteristics, health behaviors and clinical factors, as well as follow-up for events and mortality, researchers wrote.

Mercedes R. Carnethon, PhD, from the department of preventive medicine at Feinberg School of Medicine at Northwestern University, and colleagues found that the portion of patients who were normal weight at the time of incident diabetes ranged from 9% to 21% (overall 12%). Additional data found that 449 patients died during follow-up, including 178 from cardiovascular causes, 253 from noncardiovascular causes and 18 causes not classified.

Within the pooled patient sample, total (284.8 per 10,000 person-years); CV (99.8 per 10,000 person-years); and non-CV mortality (198.1 per 10,000 person-years) were higher in normal-weight patients, compared with rates among overweight or obese patients.

“These patterns are consistent for total and non-CV mortality within each cohort and present for CV mortality in CHS and FOS,” researchers wrote. “Mortality rates were markedly higher in CHS cohort participants who were older, on average, than other cohort participants.”

Once adjustments were made for demographic characteristics and BP, lipid levels, waist circumference and smoking status, HRs compared normal-weight patients with overweight/obese patients for total (HR=2.08; 95% CI, 1.52-2.85); CV (HR=1.52; 95% CI, 0.89-2.58); and noncardiovascular mortality (HR=2.32; 95% CI, 1.55-3.48).

Researchers concluded that the mechanisms to explain their findings remain unknown. They recommend further studies research normal-weight patients with diabetes as they apply to other mechanisms, such as inflammation, distribution and action of adipose tissue, atherosclerosis and position of fatty plaques and pancreatic beta-cell function.

• Source: Endocrine Today.