Comparative Effects of Glucose-Lowering Medications on Kidney Outcomes in Type 2 Diabetes: The GRADE Randomized Clinical Trial

by Selleckchem | Jul 25 2023

Importance: Type 2 diabetes (T2D) is the leading cause of kidney disease in the US. It is not known whether glucose-lowering medications differentially affect kidney function.

Objective: To evaluate kidney outcomes in the Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) trial comparing 4 classes of glucose-lowering medications added to metformin for glycemic management in individuals with T2D.

Design, setting, and participants: A randomized clinical trial was conducted at 36 sites across the US. Participants included adults with T2D for less than 10 years, a hemoglobin A1c level between 6.8% and 8.5%, and estimated glomerular filtration rate (eGFR) greater than or equal to 60 mL/min/1.73 m2 who were receiving metformin treatment. A total of 5047 participants were enrolled between July 8, 2013, and August 11, 2017, and followed up for a mean of 5.0 years (range, 0-7.6 years). Data were analyzed from February 21, 2022, to March 27, 2023.

Interventions: Addition of insulin glargine, glimepiride, liraglutide, or sitagliptin to metformin, with the medication combination continued until the HbA1c was greater than 7.5%; thereafter, insulin was added to maintain glycemic control.

Main outcomes and measures: Chronic eGFR slope (change in eGFR between year 1 and trial end) and a composite kidney disease progression outcome (albuminuria, dialysis, transplant, or death due to kidney disease). Secondary outcomes included incident eGFR less than 60 mL/min/1.73 m2, 40% decrease in eGFR to less than 60 mL/min/1.73 m2, doubling of urine albumin-to-creatinine ratio (UACR) to 30 mg/g or greater, and progression of Kidney Disease Improving Global Outcomes stage. Analyses were intention-to-treat.

Results: Of the 5047 participants, 3210 (63.6%) were men. Baseline characteristics were mean (SD) age 57.2 (10.0) years; HbA1c 7.5% (0.5%); diabetes duration, 4.2 (2.7) years; body mass index, 34.3 (6.8); blood pressure 128.3/77.3 (14.7/9.9) mm Hg; eGFR 94.9 (16.8) mL/min/1.73 m2; and median UACR, 6.4 (IQR 3.1-16.9) mg/g; 2933 (58.1%) were treated with renin-angiotensin-aldosterone inhibitors. Mean chronic eGFR slope was -2.03 (95% CI, -2.20 to -1.86) mL/min/1.73 m2 per year for patients receiving sitagliptin; glimepiride, -1.92 (95% CI, -2.08 to -1.75) mL/min/1.73 m2 per year; liraglutide, -2.08 (95% CI, -2.26 to -1.90) mL/min/1.73 m2 per year; and insulin glargine, -2.02 (95% CI, -2.19 to -1.84) mL/min/1.73 m2 per year (P = .61). Mean composite kidney disease progression occurred in 135 (10.6%) patients receiving sitagliptin; glimepiride, 155 (12.4%); liraglutide, 152 (12.0%); and insulin glargine, 150 (11.9%) (P = .56). Most of the composite outcome was attributable to albuminuria progression (98.4%). There were no significant differences by treatment assignment in secondary outcomes. There were no adverse kidney events attributable to medication assignment.

Conclusions and relevance: In this randomized clinical trial, among people with T2D and predominantly free of kidney disease at baseline, no significant differences in kidney outcomes were observed during 5 years of follow-up when a dipeptidyl peptidase 4 inhibitor, sulfonylurea, glucagonlike peptide 1 receptor agonist, or basal insulin was added to metformin for glycemic control.

Comments:

The Glycemia Reduction Approaches in Diabetes: A Comparative Effectiveness (GRADE) trial aimed to assess kidney outcomes in individuals with type 2 diabetes (T2D) using different glucose-lowering medications in combination with metformin. The study involved 5,047 participants with T2D, a hemoglobin A1c level between 6.8% and 8.5%, and estimated glomerular filtration rate (eGFR) greater than or equal to 60 mL/min/1.73 m2. The trial lasted for a mean of 5.0 years, with participants randomly assigned to receive insulin glargine, glimepiride, liraglutide, or sitagliptin in addition to metformin.

The main outcomes measured in the study were the chronic eGFR slope (change in eGFR between year 1 and the end of the trial) and a composite kidney disease progression outcome, which included albuminuria, dialysis, transplant, or death due to kidney disease. Secondary outcomes included incident eGFR less than 60 mL/min/1.73 m2, a 40% decrease in eGFR to less than 60 mL/min/1.73 m2, doubling of urine albumin-to-creatinine ratio (UACR) to 30 mg/g or greater, and progression of Kidney Disease Improving Global Outcomes stage.

The results of the trial showed that there were no significant differences in kidney outcomes among the four treatment groups. The mean chronic eGFR slope over the course of the study was similar across all groups. The composite kidney disease progression occurred in a similar percentage of patients in each group, with most of the progression being attributable to albuminuria. There were no significant differences in the secondary outcomes, and no adverse kidney events were observed related to the medication assignments.

Based on these findings, the study concluded that among individuals with T2D who were predominantly free of kidney disease at the start of the trial, the addition of a dipeptidyl peptidase 4 inhibitor (sitagliptin), sulfonylurea (glimepiride), glucagon-like peptide 1 receptor agonist (liraglutide), or basal insulin (insulin glargine) to metformin for glycemic control did not result in significant differences in kidney outcomes over a 5-year follow-up period.