ABSTRACT
Background: Evaluation of 24-hour collection accuracy is based on urinary creatinine excretion (UCr), usually using wide ranges indexed by weight. Equations that predict the expected UCr are also available. Aim: To generate an equation for estimating UCr in Chilean population and evaluate its performance in comparison to existing formulas. Material and Methods: A total of 464 24-hour urine collections from outpatients aged between 15 and 88 years old were used. Ninety percent of collections (n = 418) were randomly extracted to assess the association between absolute UCr values with sex, age, height and weight of participants. A formula was created to estimate the 24-hour UCr using a multiple linear regression model. In the remaining 10% of urine collections (n = 46), the performance of this formula and others reported in the literature were tested. Results: Age, sex and weight were significantly associated with 24-hour UCr values. The new equation was able to predict UCr values with a similar accuracy than CKD-EPI and Walser equations and outperformed other equations. Conclusions: Our equation developed with Chilean values predicts 24-hour UCr values accurately.