2016, Number 3
Rev Mex Patol Clin Med Lab 2016; 63 (3)
Salabarría GJR, Blanco MB, Santana PS, Giraudy CA, Díaz VM, Balmaseda BI, Cardona GY
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ABSTRACTRationale: Predictive equations for urinary excretion of a substance (sust) have been adjusted for the subject’s height. Body weight could be another valid alternative as an adjustment factor for the excretion index Csust/OCre. Objectives: To explore the usefulness of body weight as an adjustment factor for the Csust/OCre index in the prediction of 24-hour proteinuria in adult subjects. Material and methods: 24-hour proteinuria in 209 adult subjects (males: 28.2%; ages ≥ 60 years: 49.3%) was estimated using the Csust/OCre index constructed with urinary creatinine (OCre), Csust/D index, or urine density (D), indistinctly. The Csust/OCre index was adjusted to the subject’s body weight. Results: When the 24-hour urine collection is adequate, 24-hour proteinuria as estimated from the Csust/OCre index is lineal enough throughout the analytical range of interest. The error introduced in the estimation of 24-hour proteinuria was 1.3% when OCre was used, 18.7% after the Csust/D index, and 24% when urine density was applied. The frequency of abnormal values for 24-hour proteinuria obtained after using either OCre or Csust/D index was similar to the one observed with adequate 24-hour urine collections. Conclusions: Body weight used as an adjustment factor of the Csust/OCre index can be as valid as the subject’s height. Further studies should assess the feasibility of mathematical models based on the subject’s body weight for studying situations of clinical interest such as albuminuria and calciuria in adults.