Benefits of weight loss maintained in diabetes

By Karla Gale

NEW YORK (Reuters Health) - The therapeutic benefits achieved by loosing weight soon after type 2 diabetes is diagnosed are sustained, even if patients eventually regain the weight, according to the results of research conducted at Kaiser Permanente Northwest in Portland, Oregon.

"The main significance is that on average, patients who lose weight following diagnosis have better glycemic and blood pressure control than patients who don't, even if they subsequently regain the lost weight," study co-author Dr. Gregory A. Nichols told Reuters Health. "This is encouraging, because people who lose weight often have trouble keeping the weight off. We're saying that's OK, it's still worthwhile to lose it."

Although losing weight is decidedly beneficial in patients with diabetes, previous research that examined the effects of weight loss did not separate intentional from unintentional weight loss due to disease or examine patterns of weight change over time.

Nichols and colleagues evaluated these factors in a group of newly diagnosed type 2 diabetes patients, and excluded from the study those with severe illness or conditions associated with unintentional weight loss. The final study group included 2,574 patients who were weighed at the beginning of the study and at least five more times over the next 3 years.

Four groups were defined based on weight pattern: weight gain, weight loss, higher stable weight, and lower stable weight.

The "weight-loss" group, which consisted of 314 patients (12.2 percent), began at an average weight of 241 and reduced to 213 lb. (9.8 percent loss). After about 18 months, the subjects returned to their original weight, the authors report in an early online issue of Diabetes Care.

By contrast, the 300 subjects in the "weight-gain" group gained 6.4 percent during the first 18 months, followed by weight loss. "Notably," the investigators write, "the weight-gain and weight-loss groups began and ended at similar (average) weights."

The "higher stable weight" group, of 418 subjects and the "lower stable weight" group, of 1,542 averaged 284 lb. and 196 lb, respectively, at study entry.

At year 4, significantly fewer subjects in the weight-loss group had higher than normal blood glucose levels (measured by hemoglobin A1c levels) compared with those in the weight-gain, higher-stable-weight, and lower-stable-weight groups. Corresponding average HbA1c values at year 4 were about the same.

After consideration of the effects of age, gender, initial HbA1c level and diabetes medication use, at year 4, the odd of having high HbA1c levels were increased for subjects without initial weight loss compared with the weight-loss group.

Patients in the weight-loss group were also significantly more likely to have normal blood pressures (below 130/80 mm Hg) compared with the higher-stable-weight and the weight-gain group.

To explain these findings, Nichols suggested that "there is a lag between when the weight was regained and when the adverse effects of weight gain manifested."

"But it could also be that the weight loss benefits are indeed long-lasting," the researcher added. "We've seen this in other clinical trials where an intensively treated group had long-term benefits well after the intervention was stopped. Some have called this 'metabolic memory.'"

In future research, he and his colleagues plan to compare the outcomes of diabetic patients who maintain weight loss or continue to lose weight, and those who lose and then regain weight.

SOURCE: Diabetes Care, August 12, 2008 early online.