{"doi":"10.7326/0003-4819-150-9-200905050-00006","title":"A New Equation to Estimate Glomerular Filtration Rate","abstract":"<h4>Background</h4>Equations to estimate glomerular filtration rate (GFR) are routinely used to assess kidney function. Current equations have limited precision and systematically underestimate measured GFR at higher values.<h4>Objective</h4>To develop a new estimating equation for GFR: the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation.<h4>Design</h4>Cross-sectional analysis with separate pooled data sets for equation development and validation and a representative sample of the U.S. population for prevalence estimates.<h4>Setting</h4>Research studies and clinical populations (\"studies\") with measured GFR and NHANES (National Health and Nutrition Examination Survey), 1999 to 2006.<h4>Participants</h4>8254 participants in 10 studies (equation development data set) and 3896 participants in 16 studies (validation data set). Prevalence estimates were based on 16,032 participants in NHANES.<h4>Measurements</h4>GFR, measured as the clearance of exogenous filtration markers (iothalamate in the development data set; iothalamate and other markers in the validation data set), and linear regression to estimate the logarithm of measured GFR from standardized creatinine levels, sex, race, and age.<h4>Results</h4>In the validation data set, the CKD-EPI equation performed better than the Modification of Diet in Renal Disease Study equation, especially at higher GFR (P < 0.001 for all subsequent comparisons), with less bias (median difference between measured and estimated GFR, 2.5 vs. 5.5 mL/min per 1.73 m(2)), improved precision (interquartile range [IQR] of the differences, 16.6 vs. 18.3 mL/min per 1.73 m(2)), and greater accuracy (percentage of estimated GFR within 30% of measured GFR, 84.1% vs. 80.6%). In NHANES, the median estimated GFR was 94.5 mL/min per 1.73 m(2) (IQR, 79.7 to 108.1) vs. 85.0 (IQR, 72.9 to 98.5) mL/min per 1.73 m(2), and the prevalence of chronic kidney disease was 11.5% (95% CI, 10.6% to 12.4%) versus 13.1% (CI, 12.1% to 14.0%).<h4>Limitation</h4>The sample contained a limited number of elderly people and racial and ethnic minorities with measured GFR.<h4>Conclusion</h4>The CKD-EPI creatinine equation is more accurate than the Modification of Diet in Renal Disease Study equation and could replace it for routine clinical use.<h4>Primary funding source</h4>National Institute of Diabetes and Digestive and Kidney Diseases.","journal":"Annals of Internal Medicine","year":2009,"id":6267,"datarank":22.886215105325768,"base_score":10.14439243342898,"endowment":10.14439243342898,"self_citation_contribution":1.5216588650143472,"citation_network_contribution":21.36455624031142,"self_endowment_contribution":1.5216588650143472,"citer_contribution":21.36455624031142,"corpus_percentile":99.0,"corpus_rank":212,"citation_count":25447,"citer_count":166,"citers_with_citation_signal":166,"citers_with_endowment":166,"datacite_reuse_total":0,"is_dataset":false,"is_oa":false,"file_count":0,"downloads":0,"has_version_chain":false,"published_date":"2009-05-05","authors":[{"id":58426,"name":"Lesley A. 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Kusek","orcid":null,"position":6,"is_corresponding":false},{"id":58431,"name":"Paul Eggers","orcid":null,"position":7,"is_corresponding":false},{"id":58432,"name":"Frederick Van Lente","orcid":null,"position":8,"is_corresponding":false},{"id":58433,"name":"Tom Greene","orcid":"0000-0002-3706-7570","position":9,"is_corresponding":false},{"id":23021,"name":"Josef Coresh","orcid":"0000-0002-4598-0669","position":10,"is_corresponding":false},{"id":58434,"name":"for the CKD-EPI (Chronic Kidney Disease Epidemiology Collaboration)*","orcid":null,"position":11,"is_corresponding":false},{"id":58435,"name":"Yaping Zhang","orcid":"0000-0002-9264-3120","position":12,"is_corresponding":false},{"id":58436,"name":"Alejandro Castro","orcid":"0000-0003-0561-5971","position":13,"is_corresponding":false},{"id":58437,"name":"Paul W. Eggers","orcid":null,"position":14,"is_corresponding":false},{"id":58425,"name":"Andrew S. Levey","orcid":"0000-0003-1491-501X","position":0,"is_corresponding":true}],"reference_count":43,"raw_metadata":{"citation_network_status":"fetched"},"created_at":"2026-03-01T18:20:47.508186Z","pmid":null,"pmcid":null,"fwci":null,"citation_percentile":null,"influential_citations":0,"oa_status":null,"license":null,"views":0,"total_file_size_bytes":0,"version_count":0,"clinical_trials":[],"software_tools":[],"db_accessions":[],"linked_datasets":[],"topics":[]}