Drm Catholic University in Rome, Italy and colleagues report this finding in the January 31 online issue of Diabetes Care. They point out that a recent meta-analysis found that type 2 diabetes resolves in the majority of patients after bariatric surgery, with BPD and duodenal switch providing the greatest effect. However, data on the long term benefit are lacking.
Dr. Mingrone and colleagues followed for 10 years 50 obese patients (BMI > 35) with newly diagnosed type 2 diabetes who were treated at the Day Hospital of Metabolic Diseases in Rome with BPD or conventional medical therapy (metformin alone or with sulfonylurea or insulin).
They found that the patients who opted for BPD had less micro- and macrovascular complications at 10 years than those treated with conventional medical therapy.
After one year, all patients in the BPD group were in remission from type 2 diabetes compared with 45% in the control group (P < 0.001). None of the surgery patients experienced diabetes again during the remainder of follow-up. At 10 years, surgical patients had lost 34.6% of their initial weight, compared with a weight loss of 0.38% in the control group.
According to the investigators, the relative percentage variation in glomerular filtration rate (GFR) over 10 years, a main outcome measure, was significantly different between the groups (P < 0.001) and favored surgery. Gains in GFR were seen in the surgery group and declines in GFR indicative of diabetic nephropathy were seen in the medical group (13.6% and -45.7%, respectively).
At diagnosis of diabetes, 14.3% of the control group and 31.8% of the BPD group had microalbuminuria. After 2 years, the percentage increased in the control group to 28.6% and decreased in the BPD group to 9.1%.
After 10 years, all BPD subjects recovered from microalbuminuria, whereas in the control group microalbuminuria cases worsened, with a 39.3% prevalence of hypercreatininemia (175 µmol/L; P = 0.001).
Four major events in four different patients occurred during follow-up, all in the control group. There were three myocardial infarctions and one stroke. “The absence of episodes of myocardial infarction and stroke and the net reduction in the cardiovascular risk in the surgical group suggest that metabolic surgery had a strong impact on abating cardiovascular disease,” the investigators say.
After 10 years, the estimated probability of coronary heart disease was 0.22 in the control group versus 0.05 in the BPD group (P < 0.001).
“Our study,” Dr. Mingrone said, “is the first report in the literature showing the efficacy of bariatric surgery in reducing (or better, in avoiding) the micro- and macro-vascular complications of diabetes. Indeed, even though the patients are well controlled pharmacologically in relation to their glycemia, as it can be shown by a glycated hemoglobin lower than 6.5%, diabetes complications are not prevented but only reduced in their entity.”
“Therefore, our data are particular relevant because long-term complications of diabetes develop gradually and can eventually be disabling or even life-threatening,” Dr. Mingrone noted.
Early complications after BPD included one pulmonary (4.5%) and one wound infection (4.5%); late complications included three incisional hernias (13.6%) and two peptic ulcers (9.1%). There were no operative deaths.
Major weaknesses of the study, according to the team, are the large dropout rate, lack of randomization, and a large average BMI (roughly 50). “As a result of these factors, the population studied does not represent the general population of patients with diabetes.”
Dr. Mingrone noted that BPD is “scarcely performed in the United States, an equivalent operation might be the duodenal switch. In Europe subjects with BMI ? 35 kg/m2 and type 2 diabetes are candidates.”
“What is in my opinion, however, more important,” the researcher said, “is that by studying the mechanisms of action of BPD in preventing diabetes complication, new drugs might be discovered and used to cure diabetes, particularly in presence of insulin resistance.”
Diabetes Care, Published online January 31, 2011.