Prediabetes defined by the International Expert Committee as a risk for development of glomerular hyperfiltration.

Aims: To clarify if prediabetes defined by the International Expert Committee (Prediabetes) and/or the American Diabetes Society (Prediabetes) is a risk for incident glomerular hyperfiltration (GH).

Methods: 24,524 health examinees without diabetes, chronic kidney disease (CKD), GH and antihypertensive treatment at baseline, and repeated examinations at least twice during a mean of 5.3 years were retrospectively analysed. Diabetes was defined as fasting plasma glucose (FPG) ≥ 7.0 mmol/L and/or HbA ≥ 47 mmol/mol, CKD by estimated glomerular filtration rate (eGFR) < 60 ml/min/1.73 m and/or dipstick-positive proteinuria, and GH by upper 95th eGFR in the Japanese adults. Prediabetes was diagnosed by "HbA 42-46 mmol/mol and/or FPG 6.1-6.9 mmol/L", Prediabetes by "HbA 39-46 mmol/mol and/or FPG 5.6-6.9 mmol/L", Prediabetes for the condition met the ADA but not the IEC prediabetes definition, and the ADA-normal glucose regulation (NGR) by both HbA and FPG lower than Prediabetes. Risk of Prediabetes and Prediabetes for incident GH was examined by multivariate Cox proportional hazards model with seven covariates and probability of incident GH was calculated on the basis of it.

Results: Prediabetes was a significant risk for incident GH [adjusted HR 1.91, 95% CI 1.32-2.71] but Prediabetes was not [adjusted HR 1.22, 95% CI 0.93-1.61]. The mean (SD) probability of incident GH was 2.3 (4.5)%, 1.0 (2.3)% and 1.0 (2.4)% for Prediabetes, Prediabetes and NGR, respectively: the former was significantly larger than the latter two which were not significantly different from each other.

Conclusions: Prediabetes was an independent risk for incident GH.