title: Effect of chronic kidney disease on A1C in individuals being screened for diabetes.
abstract: 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.
  
  
  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<0.001], had higher A1C [6.0% vs. 5.8%, p<0.001], fasting glucose [5.4 vs. 5.2m mol/L, p=0.003] and fructosamine [233.7 vs. 225.8μ mol/L, p<0.001] 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.
authors.affiliation: New Cross Hospital, Clinical Chemistry, Wolverhampton WV10 0QP, United Kingdom. Electronic address: kate.shipman@doctors.net.uk.
authors.forename: Kate E
authors.initials: KE
authors.lastname: Shipman
authors.affiliation: New Cross Hospital, Clinical Chemistry, Wolverhampton WV10 0QP, United Kingdom.
authors.forename: Mohammed
authors.initials: M
authors.lastname: Jawad
authors.affiliation: New Cross Hospital, Clinical Chemistry, Wolverhampton WV10 0QP, United Kingdom.
authors.forename: Katie M
authors.initials: KM
authors.lastname: Sullivan
authors.affiliation: New Cross Hospital, Clinical Chemistry, Wolverhampton WV10 0QP, United Kingdom.
authors.forename: Clare
authors.initials: C
authors.lastname: Ford
authors.affiliation: New Cross Hospital, Clinical Chemistry, Wolverhampton WV10 0QP, United Kingdom; Research Institute, Healthcare Sciences, Wolverhampton University, Wolverhampton, United Kingdom.
authors.forename: Rousseau
authors.initials: R
authors.lastname: Gama
mesh_terms: D000328:Adult; D000368:Aged; D044466:Asian People; D015415:Biomarkers / Q000097:blood; D016009:Chi-Square Distribution; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000175:diagnosis / Q000209:etiology; D004739:England / Q000453:epidemiology; D005260:Female; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000032:analysis*; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011237:Predictive Value of Tests; D051436:Renal Insufficiency, Chronic / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology / Q000503:physiopathology; D015203:Reproducibility of Results; D012307:Risk Factors; D012720:Severity of Illness Index; D044465:White People
chemical_list: D015415:Biomarkers; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Chronic kidney disease; HbA1c; Type 2 diabetes diagnosis