Article Text
Abstract
Objective To evaluate the effects of introducing the Chronic Kidney Disease-Epidemiology Collaboration (CKD-EPI) formula for estimated glomerular filtration rate (eGFR) reporting in the adult population in routine clinical practice with clinician-directed testing.
Design Retrospective study of all creatinine measurements and calculation of eGFRs using Modification of Diet in Renal Disease (MDRD) and CKD-EPI formulae.
Setting General population, Oxfordshire, UK.
Participants An unselected population of around 660 000.
Interventions Reporting of eGFRs using MDRD or CKD-EPI formulae.
Primary and secondary outcome measures Evaluation of the effects of the CKD-EPI formula on the prevalence of different stages of chronic kidney disease (CKD).
Results The CKD-EPI formula reduced the prevalence of CKD (stages 2–5) by 16.4% in patients tested in primary care. At the important stage 2–stage 3 cut-off, there was a relative reduction of 7.5% in the prevalence of CKD stages 3–5 from 15.7% to 14.5%. The CKD-EPI formula reduced the prevalence of CKD stages 3–5 in those aged <70 but increased it at ages >70. Above 70 years, the prevalence of stages 3–5 was similar with both equations for women (around 41.2%) but rose in men from 33.3% to 35.5%. CKD stages 4–5 rose by 15% due exclusively to increases in the over 70s, which could increase specialist referral rates. The CKD classification of 18.3% of all individuals who had a creatinine measurement was altered by a change from the MDRD to the CKD-EPI formula. In the UK population, the classification of up to 3 million patients could be altered, the prevalence of CKD could be reduced by up to 1.9 million and the prevalence of CKD stages 3–5 could fall by around 200 000.
Conclusions Introduction of the CKD-EPI formula for eGFR reporting will reduce the prevalence of CKD in a primary care setting with current testing practice but will raise the prevalence in the over 70s age group. This has implications for clinical practice, healthcare policy and current prevalence-based funding arrangements.
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Footnotes
To cite: O'Callaghan CA, Shine B, Lasserson DS. Chronic kidney disease: a large-scale population-based study of the effects of introducing the CKD-EPI formula for eGFR reporting. BMJ Open 2011;1:e000308. doi:10.1136/bmjopen-2011-000308
Funding This work is underpinned by support from the National Institute for Health Research (NIHR) Oxford Comprehensive Biomedical Research Centre (BRC) and the NIHR School for Primary Care Research. The NIHR BRC and NSPCR had no role in the design and conduct of the study, data collection, management, analysis and interpretation of the data or preparation, review or approval of the manuscript.
Competing interests All authors have completed the Unified Competing Interest form at www.icmje.org/coi_disclosure.pdf (available on request from the corresponding author) and declare that (1) they have no support from companies for the submitted work, (2) they have no relationships with companies that might have an interest in the submitted work in the previous 3 years, (3) their spouses, partners or children have no financial relationships that may be relevant to the submitted work and (4) they have no non-financial interests that may be relevant to the submitted work.
Ethical approval Ethical approval was not required for this study. Clinical databases were only accessed by those with permission to do so. No individual data points were examined manually, and the data were anonymised at all stages of the analysis.
Contributors CAOC, BS and DSL contributed to the study design and concept, were involved in analysis and interpretation of data and preparation of the manuscript. CAOC is guarantor.
Provenance and peer review Not commissioned; externally peer reviewed.
Data sharing statement No additional data available.