title: Exploration of chronic kidney disease prevalence estimates using new measures of kidney function in the health survey for England.
abstract: BACKGROUND
  Chronic kidney disease (CKD) diagnosis relies on glomerular filtration rate (eGFR) estimation, traditionally using the creatinine-based Modification of Diet in Renal Disease (MDRD) equation. The Chronic Kidney Disease Epidemiology Collaboration (CKDEPI) equation performs better in estimating eGFR and predicting mortality and CKD progression risk. Cystatin C is an alternative glomerular filtration marker less influenced by muscle mass. CKD risk stratification is improved by combining creatinine eGFR with cystatin C and urinary albumin to creatinine ratio (uACR). We aimed to identify the impact of introducing CKDEPI and cystatin C on the estimated prevalence and risk stratification of CKD in England and to describe prevalence and associations of cystatin C.
  
  
  RESULTS
  Cross sectional study of 5799 people in the nationally representative 2009 and 2010 Health Surveys for England.
  
  
  METHODS
  prevalence of MDRD, CKDEPI and cystatin C-defined eGFR<60 ml/min/1.73 m(2); prevalence of CKD biomarker combinations (creatinine, cystatin C, uACR). Using CKDEPI instead of MDRD reduced the prevalence of eGFR<60 ml/min/1.73 m(2) from 6.0% (95% CI 5.4-6.6%) to 5.2% (4.7-5.8%) equivalent to around 340,000 fewer individuals in England. Those reclassified as not having CKD evidenced a lower risk profile. Prevalence of cystatin C eGFR<60 ml/min/1.73 m(2) was 7.7% and independently associated with age, lack of qualifications, being an ex-smoker, BMI, hypertension, and albuminuria. Measuring cystatin C in the 3.9% people with CKDEPI-defined eGFR<60 ml/min/1.73 m(2) without albuminuria (CKD Category G3a A1) reclassified about a third into a lower risk group with one of three biomarkers and two thirds into a group with two of three. Measuring cystatin C in the 6.7% people with CKDEPI eGFR >60 ml/min/1.73 m(2) with albuminuria (CKD Category G1-2) reclassified almost a tenth into a higher risk group.
  
  
  CONCLUSIONS
  Cross sectional study, single eGFR measure, no measured ('true') GFR.
  
  
  CONCLUSIONS
  Introducing the CKDEPI equation and targeted cystatin C measurement reduces estimated CKD prevalence and improves risk stratification.
authors.affiliation: Academic Unit of Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, United Kingdom.
authors.forename: Simon D S
authors.initials: SD
authors.lastname: Fraser
authors.affiliation: Geography & Environment, Faculty of Social and Human Sciences, University of Southampton, Southampton, SO171BJ, United Kingdom.
authors.forename: Grant
authors.initials: G
authors.lastname: Aitken
authors.affiliation: Division of Medical Sciences and Graduate Entry Medicine, University of Nottingham at Derby, Derby, DE22 3DT, United Kingdom.
authors.forename: Maarten W
authors.initials: MW
authors.lastname: Taal
authors.affiliation: Research Department of Epidemiology and Public Health, UCL (University College London), London, WC1E 6BT, United Kingdom.
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Mindell
authors.affiliation: Geography & Environment, Faculty of Social and Human Sciences, University of Southampton, Southampton, SO171BJ, United Kingdom.
authors.forename: Graham
authors.initials: G
authors.lastname: Moon
authors.affiliation: Department of Clinical Biochemistry, Royal Victoria Infirmary, Newcastle upon Tyne Hospitals NHS Foundation Trust, Newcastle upon Tyne, NE1 4LP, United Kingdom.
authors.forename: Julie
authors.initials: J
authors.lastname: Day
authors.affiliation: Renal Unit, Salford Royal NHS Foundation Trust, Salford, M6 8HD, United Kingdom.
authors.forename: Donal
authors.initials: D
authors.lastname: O'Donoghue
authors.affiliation: Academic Unit of Primary Care and Population Sciences, Faculty of Medicine, University of Southampton, Southampton, SO16 6YD, United Kingdom.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Roderick
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000652:urine; D055316:Cystatin C / Q000652:urine; D004739:England; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D051436:Renal Insufficiency, Chronic / Q000175:diagnosis / Q000453:epidemiology*; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D055316:Cystatin C