Reduced glomerular filtration rate in individuals with intermediate hyperglycemia and type 2 diabetes as defined by 1-hour post-load glucose levels according to the newly released IDF criteria

Aims: Recently, the International Diabetes Federation (IDF) has recommended determination of 1 h-post-load glucose (PG) to diagnose intermediate hyperglycemia (IH) and type 2 diabetes (T2DM). Herein, we investigate the implication of IDF recommendation in identifying subjects with chronic kidney disease (CKD). Methods: Estimated glomerular filtration rate (eGFR) was assessed on 2161 subjects classified on the basis of their fasting, 1 h and 2 h-PG, according to the IDF criteria, as having normal glucose tolerance (NGT), isolated impaired fasting glucose (iIFG), IH and T2DM. Results: Prevalence of CKD (eGFR < 60 ml/min/1.73 m2) and mildly reduced kidney function (eGFR 90–60 ml/min/1.73 m2) progressively increased at worsening of glucose tolerance. In a logistic regression analysis adjusted for several cardio-metabolic confounders, individuals with iIFG and IH exhibited a 3.48- (95 %CI = 1.01–11.00, P = 0.05) and 3.69- (95 %CI = 1.42–9.60, P = 0.007) fold increased risk of having CKD compared to the NGT group. The risk for CKD was further increased in subjects with T2DM (OR = 3.93, 95 %CI = 1.36–10.66, P = 0.007). Additionally, participants with IH and T2DM had a 1.89-fold (95 %CI = 1.38–2.60, P < 0.0001) and 2.78-fold (95 %CI = 1.97–3.98, P < 0.0001) higher risk of mildly reduced GFR compared to the NGT group. Conclusions: The 1 h-PG thresholds proposed by IDF as diagnostic for IH and T2DM are capable of identifying individuals at risk of kidney dysfunction.