High levels of fasting glucose and glycosylated hemoglobin values are associated with hyperfiltration in a Spanish prediabetes cohort. The PREDAPS Study

AIM: This study aimed to investigate whether different levels of fasting plasma glucose (FPG) and hemoglobin A1c (HbA1c) in prediabetes are associated with hyperfiltration. METHODS: A prospective cohort of 2,022 individuals aged 30–74 years took part in the PREDAPS Study. One cohort of 1,184 participants with prediabetes and another cohort of 838 participants with normal FPG and normal HbA1c were followed for 5 years. Hyperfiltration was defined as an estimated glomerular filtration rate (eGFR) above the age- and gender-specific 95th percentile for healthy control participants, while hypofiltration was defined as an eGFR below the 5th percentile. The prevalence of hyperfiltration was compared for different levels of prediabetes: level 1 of prediabetes: FPG <100 mg/dL plus HbA1c 5.7–6.0% or FPG 100–109 mg/dL plus HbA1c < 5.7%; level 2 of prediabetes: FPG <100 mg/dL plus HbA1c 6.1–6.4% or FPG 100–109 mg/dL plus HbA1c 5.7–6.0% or FPG 110–125 mg/dL plus HbA1c <5.7% and level 3 of prediabetes: FPG 100–109 mg/dL plus HbA1c 6.1–6.4% or FPG 110–125 mg/dL plus HbA1c 5.7–6.4%. RESULTS: The participants with hyperfiltration were significantly younger, had a higher percentage of active smokers, and lower levels of hemoglobin and less use of ACEIs or ARBs. Only level 3 prediabetes based on FPG 100–109 mg/dL plus HbA1c 6.1–6.4% or FPG 110–125 mg/dL plus HbA1c 5.7–6.4% had a significantly higher odds ratio (OR) of hyperfiltration (OR 1.69 (1.05–2.74); P < 0.001) compared with no prediabetes (FPG < 100 mg/dL and HbA1c < 5.7%) after adjustment for different factors. The odds ratios for different levels of HbA1c alone in prediabetes increased progressively, but not significantly. CONCLUSIONS: Level 3 of prediabetes based on FPG 100–109 mg/dL plus HbA1c 6.1–6.4% or FPG 110–125 mg/dL plus HbA1c 5.7–6.4% had a significantly higher OR of hyperfiltration compared with participants without prediabetes.