title: Development of a model to estimate 24-hour urinary creatinine excretion.
abstract: The accuracy of the spot urine analyte/creatinine ratio in estimating 24-hour excretion of the analyte is compromised because it is not adjusted for 24-hour creatinine excretion. The authors developed a model for conveniently estimating 24-hour creatinine excretion. The model was derived from 24-hour urine collections using multiple linear regression, including sex, weight, race, and age. The model was then evaluated in a validation cohort, assessing the correlation between estimated and measured 24-hour creatinine excretion and by comparing their correlation with muscle mass. Estimated creatinine excretion correlated strongly with measured creatinine excretion (r=0.80 in the entire cohort and 0.93 after eliminating patients with incomplete collections), and correlated at least as strongly as measured creatinine excretion with lean muscle mass (r=0.94 vs r=0.82, respectively). Adjusting spot urine analyte/creatinine ratios using the estimated 24-hour creatinine excretion by this convenient method can improve the accuracy of estimating 24-hour excretion of albumin, sodium, and other analytes.
authors.affiliation: Department of Public Health, Weill Cornell Medical College, New York, NY; Division of Nephrology and Hypertension, Department of Medicine, Weill Cornell Medical College, New York, NY.
authors.forename: Linda M
authors.initials: LM
authors.lastname: Gerber
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Mann
mesh_terms: D015415:Biomarkers / Q000652:urine; D002940:Circadian Rhythm; D003401:Creatine / Q000652:urine*; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006973:Hypertension / Q000652:urine*; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies
chemical_list: D015415:Biomarkers; D003401:Creatine