Real-world bariatric surgery data show microvascular protection
medwireNews: Obese patients with type 2 diabetes who undergo bariatric surgery achieve large reductions in their risk for microvascular complications, shows a real-world study.
The rates of incident microvascular disease were 6.0%, 11.8%, 16.9%, and 22.5% at 1, 3, 5, and 7 years after the patients underwent surgery, report David Arterburn (Kaiser Permanente Washington Health Research Institute, Seattle, USA) and co-researchers in the Annals of Internal Medicine.
The corresponding rates were 11.2%, 24.3%, 34.7%, and 44.2% in matched patients who continued to receive usual care. After further adjustment for additional variables including hypertension, medications, and smoking status, this equated to significant 62%, 65%, 59%, and 60% reductions in microvascular risk for the patients who had surgery.
Speaking to medwireNews, obesity specialist John Wilding (University of Liverpool, UK) described the study as “good news for those people who are advocates of bariatric surgery, because what it’s saying is […] that this has important effects on outcomes that are important to patients.”
He said: “We’ve got data in the past on cardiovascular disease, but microvascular disease hasn’t really been studied very well. This does seem to be much more convincing and is entirely consistent with what we know about complications of diabetes.”
Long-term follow-up of the SOS study, reported last year, showed significant reductions in microvascular outcomes over the long term – 20 years after surgery – but included only a small proportion of patients with diabetes.
All patients in the current study had type 2 diabetes and a BMI of 35 kg/m2 or more; 4024 underwent bariatric surgery and were matched to 11,059 patients who did not on study site, sex, age, BMI, glycated hemoglobin (HbA1c) level, insulin use, diabetes duration, and healthcare use.
Three-quarters of the patients were female, and they were aged around 48 years on average. Wilding noted that the average HbA1c level of 7.1% suggests that diabetes was in its relatively early stages for most patients.
Bariatric surgery “may not put everybody into diabetes remission, but everyone who has bariatric surgery will have improved glucose control,” said Wilding, “and what we see here is that improved control translates, as you would expect, into a very significant reduction in the complications of diabetes.”
The reduction occurred for all microvascular complications, with surgery reducing the 5-year risk for retinopathy, neuropathy, and nephropathy by 45%, 63%, and 59%, respectively.
Wilding noted the potential for seeing larger risk reductions in medically managed patients using the most effective of the more recent diabetes medications, and cautioned that this may in turn lessen the advantages of bariatric surgery. Patients in the current study underwent surgery between 2005 and 2011, and glucagon-like peptide-1 receptor agonists became available only toward the end of this period.
Wilding added that the BMI cutoff used is also “an important caveat” given the recent move in the guidelines toward allowing bariatric surgery in less severely obese people if they have poor glucose control. “If we’re going to offer that, then we would need to have the data to support that,” he said.
By Eleanor McDermid
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