The association of glucose metabolism and kidney function in middle-aged adults

BACKGROUND: Previous clinical studies have shown that various measures of glucose metabolism are associated with a risk of chronic kidney disease in different populations, but results were not consistent. In this study we assessed measures of glucose metabolism and their association with kidney function in a population-based study. METHODS: The Netherlands Epidemiology of Obesity study is a population-based cohort study of middle-aged men and women. We categorized the study population according to glycaemic levels into normoglycaemia (reference group), pre-diabetes mellitus (pre-DM), known DM and newly diagnosed DM. Outcome variables were serum creatinine, estimated glomerular filtration rate (eGFR), glomerular hyperfiltration (defined as an eGFR >90th percentile; >102 mL/min/1.73 m(2)) and micro-albuminuria. We examined the association between measures of glucose metabolism [fasting glucose, haemoglobin A1c (HbA1c), fasting insulin, glucose area under the curve (AUC), insulin AUC, Homoeostatic Model Assessment of Insulin Resistance (HOMA-IR), HOMA of β-cell function (HOMA-B) and disposition index] and measures of kidney function. RESULTS: Of the total population (N = 6338), 55% of participants were classified as normoglycaemic (reference), 35% as pre-DM, 7% as DM and 4% as newly diagnosed DM. Compared with the reference group, diagnosed and newly diagnosed DMs were associated with a slightly higher trend in eGFR {+2.1 mL/min/1.73 m(2) [95% confidence interval (CI) −0.2–4.4] and +2.7 mL/min/1.73 m(2) [95% CI −0.3–5.7], respectively}. A 1% higher HbA1c was associated with increased odds of hyperfiltration [odds ratio (OR) 1.41 (95% CI 1.06–1.88)]. Higher levels of fasting plasma glucose, AUC glucose and HOMA-B were associated with hyperfiltration. Fasting insulin, AUC insulin and HOMA-IR were not associated with hyperfiltration. The OR of microalbuminuria was 1.21 (95% CI 1.04–1.42) per mmol/L higher fasting glucose concentrations. CONCLUSIONS: Both fasting and post-prandial glucose and HOMA-B, but not measures of insulin resistance, were associated with glomerular hyperfiltration, while fasting glucose was also associated with microalbuminuria.