State-of-the-art Medical Therapy Versus Roux-en-Y Gastric Bypass Alone for Treatment of Early Diabetic Kidney Disease.

OBJECTIVE: Type 2 diabetic kidney disease (DKD) is the most common global cause of kidney disease and failure. Obesity is a major risk factor for DKD due to its causal relationship with diabetes, hypertension, and other factors promoting kidney disease. We therefore investigated whether metabolic surgery such as Roux-en-Y gastric bypass is more effective than state-of-the-art medical therapy (i.e., renin-angiotensin-aldosterone system, sodium-glucose co-transporter 2 inhibitors, and glucagon-like peptide-1 receptor agonists) in treating DKD. DESIGN AND METHODS: In a post hoc analysis of the Microvascular Outcomes after Metabolic Surgery trial, we compared the likelihood of regression of microalbuminuria as the primary endpoint and other renal and metabolic secondary endpoints in a population of patients with obesity, type 2 diabetes, microalbuminuria, and early chronic kidney disease followed for 24 months. Nine patients underwent Roux-en-Y gastric bypass, and 24 patients were on state-of-the-art medical therapy. RESULTS: The gastric bypass arm had a significantly higher rate of regression of microalbuminuria (P < .001), borderline significant reduction in mean urine albumin-to-creatinine ratio (P = .055), and much greater weight loss (P = .001). There were no statistically significant differences between arms in estimated glomerular filtration rate, risk of developing estimated glomerular filtration rate <60 mL/min/1.73 m2 over 5 years, mean hemoglobin A1c, systolic blood pressure, low-density lipoprotein cholesterol, or the American Diabetes Association triple endpoint. CONCLUSION: We found that metabolic surgery offers more kidney protection than state-of-the-art triple therapy for DKD at 24 months. Prospective studies in this area are necessary to better define the benefits and risks of medical versus surgical treatment of DKD.

Urinary Metabolomic Changes Accompanying Albuminuria Remission following Gastric Bypass Surgery for Type 2 Diabetic Kidney Disease.

In the Microvascular Outcomes after Metabolic Surgery randomised clinical trial (MOMS RCT, NCT01821508), combined metabolic surgery (gastric bypass) plus medical therapy (CSM) was superior to medical therapy alone (MTA) as a means of achieving albuminuria remission at 2-year follow-up in patients with obesity and early diabetic kidney disease (DKD). In the present study, we assessed the urinary 1H-NMR metabolome in a subgroup of patients from both arms of the MOMS RCT at baseline and 6-month follow-up. Whilst CSM and MTA both reduced the urinary excretion of sugars, CSM generated a distinctive urinary metabolomic profile characterised by increases in host-microbial co-metabolites (N-phenylacetylglycine, trimethylamine N-oxide, and 4-aminobutyrate (GABA)) and amino acids (arginine and glutamine). Furthermore, reductions in aromatic amino acids (phenylalanine and tyrosine), as well as branched-chain amino acids (BCAAs) and related catabolites (valine, leucine, 3-hydroxyisobutyrate, 3-hydroxyisovalerate, and 3-methyl-2-oxovalerate), were observed following CSM but not MTA. Improvements in BMI did not correlate with improvements in metabolic and renal indices following CSM. Conversely, urinary metabolites changed by CSM at 6 months were moderately to strongly correlated with improvements in blood pressure, glycaemia, triglycerides, and albuminuria up to 24 months following treatment initiation, highlighting the potential involvement of these shifts in the urinary metabolomic profile in the metabolic and renoprotective effects of CSM.