title: Measuring the population burden of chronic kidney disease: a systematic literature review of the estimated prevalence of impaired kidney function.
abstract: BACKGROUND
  Internationally, there have been substantial efforts to improve the early identification of chronic kidney disease (CKD), with a view to improving survival, reducing progression and minimizing cardiovascular morbidity and mortality. In 2002, a new and globally adopted definition of CKD was introduced. The burden of kidney function impairment in the population is unclear and widely ranging prevalence estimates have been reported.
  
  
  METHODS
  We conducted a systematic literature review, searching databases to June 2009. We included all adult population screening studies and studies based on laboratory or clinical datasets where the denominator was clear. Studies reporting prevalence estimates based on at least one eGFR <60 mL/min/1.73m(2) or elevated creatinine above a stated threshold were included. Study design and quality were explored as potential factors leading to heterogeneity.
  
  
  RESULTS
  We identified 43 eligible studies (57 published reports) for inclusion. Substantial heterogeneity was observed with estimated prevalence (0.6-42.6%). The included studies demonstrated significant variation in methodology and quality that impacted on the comparability of their findings. From the higher quality studies, the six studies measuring impaired kidney function (iKF) using estimated glomerular filtration rate in community screening samples reported a prevalence ranging from 1.7% in a Chinese study to 8.1% in a US study, with four reporting an estimated prevalence of 3.2-5.6%. Heterogeneity was driven by the measure used, study design and study population.
  
  
  CONCLUSIONS
  In the general population, estimated iKF, particularly eGFR 30-59 mL/min/1.73m(2) was common with prevalence similar to diabetes mellitus. Appropriate care of patients poses a substantial global health care challenge.
authors.affiliation: NHS Grampian, Aberdeen, UK.
authors.forename: Keith
authors.initials: K
authors.lastname: McCullough
authors.forename: Pawana
authors.initials: P
authors.lastname: Sharma
authors.forename: Tariq
authors.initials: T
authors.lastname: Ali
authors.forename: Izhar
authors.initials: I
authors.lastname: Khan
authors.forename: William C S
authors.initials: WC
authors.lastname: Smith
authors.forename: Alison
authors.initials: A
authors.lastname: MacLeod
authors.forename: Corri
authors.initials: C
authors.lastname: Black
mesh_terms: D002908:Chronic Disease; D017281:Cost of Illness; D014943:Global Health; D005919:Glomerular Filtration Rate / Q000502:physiology; D006801:Humans; D007668:Kidney / Q000503:physiopathology; D007674:Kidney Diseases / Q000453:epidemiology* / Q000503:physiopathology; D015995:Prevalence; D012189:Retrospective Studies