Introduction:
The use of parametric equations to estimate glomerular filtration (GF) in paediatrics is a trending question. However, there is not enough information referring to paediatric oncology. Aim: To study the potential correlation between the GF estimated by the modified Schwartz (SGFR) and Gao (GGFR) formulas, and measured by creatinine clearance (CrCl) obtained from a 24hour urine sample, all expressed in ml/min/1.73m2 to see if they can be used interchangeably.
Material and methods:
Retrospective study. Charts from 269 children less than 18 years old from the haematooncology unit were reviewed. The following data was collected: demographics, anthropometric data, serum creatinine and CrCl. Patients who lacked any of these were excluded. Statistical analysis was done using SPSS.
Results:
Sixtythree patients (38 male, 25 female) were included. Mean age was 7.5 (range 0.118) years. The most common diagnosis was haematological malignancy (33), central nervous system tumours (15) and Wilms tumour (7). Medium serum creatinine, SGFR, GGFR and CrCl was 0.42 mg/dl (0.120.83), 133.36 (58.39281.88), 107.88 (61.48128.82) and 152.3 (24.52475.34), respectively. Data follows a normal distribution (KolmogorovSmirnov test). A significant difference, by paired ttest, between SGFR and CrCl was found, with an average difference in their values of 18.93 (95% confidence interval of [4,833]) with a correlation coefficient (CC) of 0.6 (p<0.09), with a significant reliability analysis. Similarly, we found a statistically significant difference between GGFR and CrCl with an average difference of 44.4 (95% confidence interval of [27.5361]), with a CC of 0.3 (p <0.02), with a nonsignificant reliability analysis.
Conclusions:
In oncologic patients, there is significant correlation between CrCl and SGFR and GGFR but the CC is low. SGFR is more accurate than GGFR if CrCl is used as the gold standard. We cannot conclude that SGFR, GGFR and CrCl are equivalent considering that the difference between the mean values is too large and significant.
