Prediabetics may gain most in long term from bariatric surgery
medwireNews: Research shows that the largest long-term reductions in microvascular complications around 20 years after bariatric surgery for obesity are seen among patients who had prediabetes at the time of surgery.
After a median follow-up of 19 years of 4032 of the original 4047 patients in the Swedish Obese Subjects study, the microvascular outcome rate in the 2001 surgical patients was 6.3 events per 1000 person–years, compared with 10.9 events per 1000 person–years among 2031 patients who did not undergo surgery and were matched to the surgery patients on 18 variables, including age, weight, height, and waist and hip circumferences.
The patients who underwent surgery did so in their late 40s to early 50s, at which point 301 had prediabetes, 159 had diabetes detected in pre-surgery screening, and 184 had established diabetes, with the others being normoglycemic. Although all these groups saw benefits, the size of that benefit varied between them.
The relative risk reductions for microvascular risk were 82% for patients with prediabetes, and 61%, 46%, and 37%, for those with newly detected diabetes, established diabetes, and normoglycemia, respectively. And the effect of glycemic status on the size of treatment benefit remained after further adjustment for baseline variables.
The overall benefit was driven largely by changes in the risk for retinopathy, the most common complication. Surgery also significantly reduced the risk for diabetic kidney disease in patients with baseline prediabetes or established diabetes. Neuropathy was very rare overall, although it was most common in patients with established diabetes at baseline, which was true of all complications.
The microvascular complication risk was reduced by surgery even in patients who had developed diabetes by the 15-year follow-up, although those who remained free of diabetes benefited the most, with rates of 8.0 versus 25.2 events per 1000 person–years for those without and with diabetes at 15 years after surgery.
“Our results suggest that long-lasting remission of diabetes is important to prevent microvascular events,” say Lena Carlsson (University of Gothenburg, Sweden) and colleagues. But they caution that “it is not known if patients cycled between remission and relapse before this timepoint.”
Patients with baseline prediabetes benefited from surgery irrespective of whether they had developed diabetes within 15 years after surgery. This, coupled with the fact that patients who underwent surgery had lower fasting glucose levels at the 2-year follow-up than those who did not, led the researchers to speculate that “the reduced risk of microvascular events after bariatric surgery might be explained not only by prevention of diabetes, but also by reductions in slightly elevated glucose concentrations.”
This finding “emphasises the importance of treating prediabetes,” they write in The Lancet Diabetes & Endocrinology.
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