Spot urine protein to creatinine ratio

Should we therefore employ this recommendation in future care? The first step to answering this question is to look at the quality of the reporting in the study. The pediatric nephrology community unfortunately does not have a good track record when it comes to reporting randomized controlled clinical trials using the CONsolidated Standards Of Reporting Trials (CONSORT) criteria or including the appropriate figures and checklists [8]. Trial reporting in field of pediatric renal transplantation has been criticized for its poor compliance with the CONSORT criteria. Of particular concern, the reporting of the essential components of the Methods, Results, and Discussion sections has been described as unsatisfactory [9]. The Enhancing the QUAlity and Transparency Of health Research (EQUATOR) statement (http://www.equator-network.org/) provides a one-stop source for standardized reporting guidelines for common study designs. Since the study by EM Yang et al. [4] is a retrospective cross-sectional study, the authors should have employed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) Statement guidelines used for observational studies. This guideline can also be used for case–control and cohort studies. Many journals have embraced this stringent approach including the British Medical Journal [10], the Lancet [11], and PLOS Medicine [12]. For example, according to the STROBE guidelines, EM Yang et al. [4] should have included the study design in their title. Unfortunately, however, Pediatric Nephrology requires succinct titles that would preclude the use of “A retrospective study…” The authors did include a flow chart [checklist item 13 (c)]. Another guideline that should have been followed but was not includes consistently providing unadjusted estimates and, if applicable, confounder-adjusted estimates and their precision (e.g., 95% confidence interval)—standard 16 (a); this is one of several examples. Although Pediatric Nephrology has not yet embraced the EQUATOR statement, the publication of a very important study, such as the one by EM Yang et al., [4] should perhaps trigger a discussion about the importance of embracing such standards, especially when striving for a higher impact factor.

One other question that remains to be answered concerns the best approach for validating the proposed formula for correcting the daily protein excretion estimate based on the first morning void. EM Yang et al. [4] used the entire cohort to generate the formula. The authors could have divided their study participants into one cohort of 160 patients to generate the formula and a second cohort composed of the remaining patients to validate the formula, akin to other biomarker discovery studies [13, 14]. There are five stages for biomarker development, and the later stages focus on epidemiologic concepts within a diagnostic, prognostic, and screening framework to determine if new markers will advance clinical care [15]. Future studies should consider performing both an internal and an external prospective validation of the proposed formula to firmly establish a revised clinical practice and, in this case, to move from the current simple Prot/Cr to the modified approach proposed by the authors.

Nonetheless, EM Yang et al. [4] applied a number of critically rigorous criteria, such as excluding specific samples and carefully applying the appropriate tests to generate a robust and superior approach to calculating 24-h UProt from a spot sample. The limitations of the study are not discussed in detail, and the bias of using the last 10 mL of the 24-h urine collection for the spot sample limits this new approach to the first morning void. Future prospective studies should include children in various demographic situations, clinical status, and social status to improve the validity and generalizability of these findings. One limitation that was identified, i.e., the potential bias owing to the elimination of 224 participants, could have easily been addressed by comparing key demographic features of the eliminated participants and the included participants.