Bariatric Surgery Benefits Diabetic Renal, Retinal Disease

February 07, 2013

ISTANBUL — Physicians from the United Kingdom have reported the first data showing that bariatric surgery in morbidly obese patients with type 2 diabetes may be of benefit for the renal and retinal complications of diabetes.

Presenting the findings from a small study in 2 posters here at the Excellence in Diabetes 2013 meeting, Carel Le Roux, MD, from Imperial College London, United Kingdom, noted that they had also been partly reported in a recent letter published in Diabetes Care. He told Medscape Medical News, "Bariatric surgery was used before to treat glycemia, and what we are seeing now is that we can actually use it to treat the entire metabolic syndrome and reverse some of the end-organ damage."

Dr. Le Roux stressed, however, that such weight-loss surgery "must be used as an add-on therapy to medicine because these patients have decades of disease that can't be reversed in 2 days. We were probably overselling it before. It's true that in our hands — and also in some of the randomized controlled studies — about 34% to 41% of patients do go into 'remission' of diabetes, but it's not 80% as we thought before. But even these people who go into remission for their glycemia are not optimally treated as far as their lipids and their BP are concerned." What surgery can achieve is a large reduction in the number of medications people have to take and "stabilization of the disease," he says.

Dr. Carel Le Roux

One-year results show that bariatric surgery improves markers of kidney disease and might ultimately halt the progression of diabetic nephropathy, says Dr. Le Roux. An overt benefit for retinopathy was not as apparent at 1 year, but he hopes it is only a matter of time before improvement is seen in this outcome, too.

The results are also important in that they demonstrate the safety of bariatric surgery on microvascular complications, he said; paradoxically, the rapid improvements in glycemia that often result from weight-loss surgery can exacerbate microvascular complications, so this had been a concern.

Bariatric Surgery May Halt Progression of Diabetic Nephropathy

The Imperial College London researchers performed a prospective case-control study comprising 75 patients who underwent bariatric surgery —gastric bypass, sleeve gastrectomy, or gastric banding procedures — and 71 who received best medical care. The primary end point for kidney disease was change in urine albumin-creatinine ratio (ACR) from baseline to 1 year after the intervention. Of the patients, 41% from the surgical group and 49% from the medical group had baseline albuminuria.

At 1 year, urine ACR improved in the surgical cohort from 10.4 to 5.7 mg/mmol, whereas it worsened in the best medical treatment group, from 14.2 to 15.1mg/mmol. "Bariatric surgery resulted in improvements in ACR. It may halt or improve the progression of diabetic kidney disease," say the researchers in their poster.

"It turns out that the most sensitive of all the organs appears to be the kidney, so you can show very significant reductions in kidney damage markers such as ACR," Dr. Le Roux observed to Medscape Medical News.

Of the patients undergoing surgery, 67 had complete retinal data, and they were compared with 66 controls who got best medical care. There was a 16% improvement in retinopathy 1 year after bariatric surgery compared with the best medical care (P = .0054). Nine patients (30%) with preexisting retinopathy who underwent surgery returned to grade 0 as compared with 5 (15%) in the best-medical-care cohort.

"The effects of surgery to halt and in some cases reverse retinopathy were encouraging. Improvement of retinopathy is rarely encountered, and the rates of deterioration observed after surgery, albeit in a small number of patients, did not exceed the rates reported in the literature," he and his colleagues observe. "We hope that after 3, 4, or 5 years, we may even start seeing an improvement in retinopathy," Dr. Le Roux noted.

Although encouraging, the results for microvascular complications need to be confirmed in larger, randomized, controlled clinical trials, said Dr. Le Roux.

Remission of type 2 diabetes occurred in 55% of the surgical cohort and 11% of the best medical group, and surgery resulted in greater improvements in body-mass index (BMI) and glycated hemoglobin (A1c) when compared with best medical therapy. Blood pressure (BP) improved after surgery but worsened after medical therapy.

The improvements in microvascular complications were seen in the context of a reduction in medication usage among those in the surgical group, but did not correlate with reductions in weight, glycemia, or BP.

Key Is to Use Surgery as Add-On Therapy

Dr. Le Roux says the key to successful management of these patients postsurgery is the use of International Diabetes Federation (IDF) criteria for optimization of the metabolic state. This dictates an A1c of 42 mmol/mol (6%) or less, no hypoglycemia, total cholesterol less than 4 mmol/L, LDL cholesterol less than 2 mmol/L, triglycerides less than 2.2mmol/L, BP less than 135/85 mm Hg, more than 15% weight loss, and reduced medication.

"We should continue to treat lipids, BP, etc and use surgery as an add-on therapy to medicine; we are going to get much better outcomes than just using surgery on its own or just using medicine on its own. We need to get away from this antagonism between surgery and medicine and go for synergism.

"If you have patients who are at very high risk, morbidly obese with type 2 diabetes and microvascular disease, these are the patients with the highest direct healthcare costs to any health system, and surgery will generate a massive benefit — you reduce direct healthcare costs and you reduce their risks of having really expensive things like dialysis."

Bariatric surgery will not make you thin, and it will not make you happy, but it will make you healthier. Dr. Carel Le Roux

Dr. Le Roux says his message to patients is: "Bariatric surgery will not make you thin, and it will not make you happy, but it will make you healthier and more functional. The benefit to the patient is that there is a significant reduction in medication, so now they don't need 3 drugs for their glucose; they just need metformin. They don't need 2 drugs for their lipids; they just need a small dose of a statin. They don't need 4 drugs for their BP; they need an ACE inhibitor; so that's a reduction in medication load. The real benefit to them is now suddenly they can tie their shoelaces and more important, they can see their feet."

The authors have disclosed no relevant financial relationships.

Excellence in Diabetes 2013: Posters PP05 and PP20. Presented February 7, 2013.

Diabetes Care. 2012;35:e81. Abstract


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