Effect of Chronic Kidney Disease on A1C in Individuals Being Screened for Diabetes.

Objective: Glycated haemoglobin (A1C) has been recommended for the diagnosis of type 2 diabetes mellitus. Chronic kidney disease (CKD) is reported to increase A1C. The prevalence of CKD and its association with A1C as a diagnostic test for type 2 diabetes screening in a community population was studied.Research design and methods: Age, gender, ethnicity (white/South Asian), haemoglobin, A1C, fasting glucose and fructosamine were compared in participants with estimated glomerular filtration rate (eGFR) 30-59 (CKD 3) and >= 60 ml/min/1.73 m(2) using chi-squared or t-tests. Multivariable linear regression analyses were performed with A1C as the dependent variable; remaining variables were forced into a model to identify correlates with A1C. Data were parametric and expressed as means.Results: Of 949 participants 83.7% had eGFR >= 60, 16.3% had CKD 3 and only 2 had eGFR <30 (CKD >= 4). Compared with eGFR >60, patients with CKD 3 were older [p <0.0011, had higher A1C [6.0% vs. 5.8%, p <0.001], fasting glucose [5.4 vs. 5.2 mmol/L, p = 0.0031 and fructosamine [233.7 vs. 225.8 mu mol/L, p <0.0011 but lower haemoglobin [p = 0.006]. After adjustment, gender and CKD stage were not associated with A1C. A1C was associated (p <0.05) positively with age, South Asian ethnicity, fasting glucose and fructosamine and inversely with haemoglobin levels.Conclusions: Severe CKD (stage >= 4) is rare in primary care patients being screened for type 2 diabetes and its impact on A1C could not be evaluated. Although A1C is higher among patients with CKD stage 3 compared to those with eGFR >60, this appeared to be due to the confounding effect of other variables rather than the presence of CKD. (C) 2014 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.