Bariatric surgery may reverse complications related to diabetes, including regenerating damaged nerves, according to researchers from the University of Michigan. The study team led by the University of Michigan Health Department of Neurology followed more than 120 patients who underwent bariatric surgery for obesity over two years after the procedure. They found that all metabolic risk factors for developing diabetes, such as high glucose and lipid levels, improved outside of blood pressure and total cholesterol.
"Our findings suggest that bariatric surgery likely enables the regeneration of the peripheral nerves and, therefore, may be an effective treatment for millions of individuals with obesity who are at risk of developing diabetes and peripheral neuropathy," said senior author, Dr Brian C Callaghan, a neurologist at University of Michigan Health and the Eva L Feldman, Professor of Neurology at U-M Medical School.
Researchers assessed two primary measures for peripheral neuropathy in patients with obesity by taking skin biopsies that show the nerve fibre density in the thigh and the leg. A total of 79 patients completed in-person follow-up (age 46.0 ± 11.3 years [mean ± SD], 73.4% female). Participants lost a mean of 31.0 kg (SD 18.4), and all metabolic risk factors improved except for blood pressure and total cholesterol. Following bariatric surgery, one of the primary peripheral neuropathy outcomes improved (IENFD proximal thigh, +3.4 ± 7.8, p<0.01), and cardiovascular autonomic neuropathy (E/I ratio −0.01 ± 0.1, p=0.89) and retinopathy (deviation −0.2 ± 3.0, p=0.52) were stable. Linear regression revealed that a greater reduction in fasting glucose was associated with improvements in retinopathy (mean deviation point estimate −0.7, 95% CI −1.3, −0.1).
Compared to previous studies of medical weight loss, when providers guide a patient's weight loss goals, bariatric surgery led to better metabolic improvements and even greater improvements in peripheral neuropathy.
Treatment for peripheral neuropathy currently focuses on pain, including oral medications such gabapentin and sodium channel blockers, topical analgesics and non-medical treatments, like exercise and cognitive behavioural therapy.
"Given the natural history of peripheral neuropathy decline in patients with obesity, even stability in nerve fibre density may be considered a successful result," said first author, Dr Evan Reynolds, lead statistician for the NeuroNetwork for Emerging Therapies at Michigan Medicine. "Therefore, our findings of stability of nerve fibre density in the leg and improvement in nerve fibre density at the thigh indicate that bariatric surgery may be a successful therapy to improve or reverse peripheral neuropathy for patients with long-term metabolic impairment."
The findings were reported in the paper, ‘The effect of surgical weight loss on diabetes complications in individuals with class II/III obesity’, published in Diabetologia. To access this paper, please click here