Lower HbA1c Linked to Lower AKI Risk in Chronic Kidney Disease

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Better control of blood glucose levels may reduce the risk of AKI in adults with type 2 diabetes and CKD, according to an analysis of US and Swedish data in Diabetes Care.

The study included data on two observational cohorts of patients with type 2 diabetes and confirmed stage G3 to G5 CKD receiving routine care in one US and one Swedish health system. The US cohort, drawn from the Geisinger Health System in Pennsylvania, consisted of 22,877 patients: median age 72 years, 55% female, and estimated glomerular filtration rate (eGFR) 52 mL/min/1.73 m2. The Swedish cohort included 12,157 patients from the Stockholm Creatinine Measurements (SCREAM) project: median age 77 years, 50% women, eGFR 51 mL/min/1.73 m2. Baseline HbA1c and time-varying HbA1c were evaluated for incident AKI, defined as a 0.3 mg/dL or greater increase in creatinine over 48 hours or a 1.5-fold increase over 7 days.

A total of 7060 AKI events occurred over 3.1 years of follow-up in the US cohort and 2619 events over 2.3 years in the Swedish cohort. On adjusted analysis, the risk of AKI was increased by about 30% for patients with baseline HbA1c over 9%, compared to values of 6% to 6.9%: hazard ratio (HR) 1.29 in the US cohort and 1.33 in the Swedish cohort. Particularly in the US cohort, there was a J-shaped association between baseline HbA1c and AKI, with higher risk at both the lower and higher end of the range.

The findings were similar on analysis of time-varying HbA1c and on stratified analysis with death as a competing risk. Higher and lower HbA1c values were also associated with increased mortality. At baseline HbA1c of 9% or higher, HRs for mortality were 1.30 in the US and 1.46 in the Swedish cohort. At HbA1c under 6%, HRs were 1.11 in both cohorts [Xu Y, et al. Glycemic control and the risk of acute kidney injury in patients with type 2 diabetes and chronic kidney disease: Parallel population-based cohort studies in U.S. and Swedish routine care. Diabetes Care 2020; 43:2975–2982. doi: 10.2337/dc20-1588].