Prediabetes increases the risk of kidney damage and could be a target for early intervention to prevent chronic kidney disease (CKD), researchers concluded.

In a prospective cohort study of 1,261 middle-aged non-diabetic individuals from the Norwegian general population, a team led by Toralf Melsom, MD, PhD, of the University Hospital of North Norway in Tromsø, found that prediabetes was an independent risk factor for glomerular hyperfiltration and increased albuminuria, according to a report published online ahead of print in the American Journal of Kidney Diseases (AJKD).

“If a patient has borderline elevated glucose levels found by their primary physician they should start lifestyle changes with respect to diet and physical activity to preventing diseases like diabetes and kidney disease,” Dr. Melsom said in a news release from the National Kidney Foundation (NKF), which publishes AJKD.

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Previous longitudinal studies assessing the association between prediabetes and kidney function used eGFR to assess changes in GFR, but eGFR has low precision, especially in the higher range of GFRs, the authors pointed out. To overcome the limitations of eGFR, they measured GFR (mGFR) by iohexol clearance.

“To our knowledge, no prior study of the general population has assessed the longitudinal association between prediabetes and mGFR,” the authors wrote.

The investigators defined hyperfiltration as an mGFR value greater than the 90 percentile adjusted for age, sex, weight, and height. They defined high-normal ACR as greater than 10 mg/g at follow-up. Dr. Melsom’s group used 2 definitions of prediabetes: a fasting glucose level of 100 to 125 mg/dL and/or HbA1c level of 5.7% to 6.4%, according to American Diabetes Association (ADA) criteria; and a fasting glucose level of 110 to 125 mg/dL and/or HbA1c level of 6.0% to 6.4%, according to the International Expert Committee (IEC) of 2009. At baseline, 595 participants had prediabetes based on ADA criteria and 169 had prediabetes based on IEC criteria. The study population had a median observation time of 5.6 years.

In a fully adjusted model, prediabetes based on ADA and IEC criteria was associated with 30% and 79% increased odds of hyperfiltration, respectively, and 24% and 71% increased odds of a high-normal ACR, respectively.

“Prediabetes is very common and it is strongly associated with changes in kidney function and the presence of albuminuria, which are risk factors for development of serious kidney and cardiovascular disease,” said NKF president Jeffrey Berns, MD. “However, studies like this underscore how important it is to identify those with prediabetes so lifestyle changes and physician management can potentially stem declines in kidney function.”