Association of elevated glycosylated hemoglobin A1c with hyperfiltration in a middle-aged and elderly Chinese population with prediabetes or newly diagnosed diabetes: a cross-sectional study

BACKGROUND: To examine whether elevated glycosylated hemoglobin A1c (HbA1c) is associated with hyperfiltration in a middle-aged and elderly Chinese population. METHODS: Anthropometric and biochemical examinations were performed in 2491 individuals from the general population, aged 40–79 years, who participated in the Huaian Diabetes Prevention Program. The estimated glomerular filtration rate (eGFR) was calculated from creatinine levels using the CKD-EPI formula. Hyperfiltration was defined as eGFR >90(th) percentile. RESULTS: After adjustment [for age, gender, waistline, body mass index, blood pressure, smoking, alcohol consumption, cholesterol, log(triglycerides), high-density lipoprotein, low-density lipoprotein, serum uric acid, sodium intake, hypertension, and use of angiotensin converting enzyme inhibitors or angiotensin receptor blockers], HbA1c and fasting plasma glucose (FPG) were found to be independently positively associated with eGFR. Additionally, after multivariate adjustment, the odds ratios (95 % CI) for hyperfiltration calculated for a 1-unit increase in HbA1c and FPG were 1.396 (1.089–1.790) and 1.306 (1.117–1.526), respectively. Compared with participants with HbA1c levels <5.7 %, the odds ratios (95 % CI) for hyperfiltration were 2.344 (1.025–5.364) in participants with HbA1c levels of 6.21–6.49 %, and 2.965 (1.537–5.720) in those with HbA1c levels ≥6.5 %. CONCLUSION: Elevated HbA1c (≥6.21 %) is associated with an increased odds of hyperfiltration in middle-aged and elderly Chinese. Longitudinal studies are needed to explore whether hyperfiltration increases the odds of diabetic nephropathy in individuals with prediabetes.