Shelley Wood

October 04, 2012

October 3, 2012 (Berlin, Germany) — Patients newly diagnosed with diabetes who gain, rather than lose or maintain, weight are at a significantly increased risk of cardiovascular death, new Swedish data suggest [1]. The findings cast a light on a group that is rarely the focus of diabetes studies, lead author Dr Johan Bodegård (Center for Excellence, AstraZeneca Nordic, Södertälje, Sweden) told heartwire . Most studies, he points out, focus on baseline weight of participants but fail to track changes over time, and if they do, they look at diabetics who manage to shed some pounds, not put them on.

Bodegård and colleagues at the Swedish universities of Uppsala and Linköping collected data from 84 primary-care centers in Sweden, looking at all patients with a new diagnosis of type 2 diabetes or newly prescribed glucose-lowering drugs between 1999 and 2008. Patients younger than 35 or older than 79, patients with a previous diagnosis of CVD, and patients with no baseline or follow-up body-mass index (BMI) measurement were excluded from the analysis. This left a total of 8486 patients who had their BMI measured at baseline and again at least one year later.

The majority of patients, they note, either lost weight (32.2%) or maintained their weight (53.4%), but more than 1200 patients (14.4%) actually saw their weight increase.

After a mean follow-up of 4.6 years, diabetic patients who lost weight were no more likely to die of cardiovascular or all-cause mortality than subjects whose weight remained the same. While this finding was somewhat surprising, Bodegård noted, it may in part reflect that the study did not capture the "healthier" subjects who did not return to their doctors for follow-up BMI measurement.

"Of course if you are healthy, young, well-educated, etc, you think, okay, I go home, I eat better, I lose weight, I deal with this," he said. "So we miss a lot of healthy patients. But the other patients, those who are a little trickier to handle, they are more likely to be tracked in the office setting."

By contrast, patients with type 2 diabetes who gained weight over follow-up (a BMI increase of at least one unit) demonstrated a statistically significant 63% increase in CV death and a 34% increase in all-cause death. Survival analyses were adjusted for age, gender, baseline BMI, previous angina, education level, marital status, and glucose-lowering drugs.

"The clear message is that weight gain is extremely hazardous to patients," Bodegård said. "It's not so frequent, but it's dangerous."

Just how the excess risk can be explained is a focus of ongoing research, he added. One explanation may be the type of glucose-lowering drug used in the different study groups. Metformin use was much more common in the group of patients whose BMIs declined over the course of the study as compared with patients whose BMIs climbed (25.5% vs 17.9%). By contrast, sulfonylureas were used in 12.8% of weight-gainers, but in just 5.1% of patients who lost weight.

"Sulfonylureas were used rather frequently in the weight-gain group, and we know that this drug puts patients at increased risk of hypoglycemia," Bodegård explained, "and if you get hypoglycemia, you are at higher risk of MI and CD death."

AstraZeneca sponsored the study. Bodegård is an employee of AstraZeneca.