Translating Best Evidence into Best Care EDITOR’S NOTE: Studies for this column are identified using the Clinical Queries feature of PubMed, “hand” searching JAMA, JAMA Pediatrics, Pediatrics, The Journal of Pediatrics, and The New England Journal of Medicine, and from customized EvidenceUpdates alerts. EBM PEARL: PREVALENCE RATIO (PR): The PR is the ratio of disease prevalence in the exposed versus the non-exposed groups. The PR makes far fewer appearances in the medical literature than the odds ratio (OR) when measuring the association of an exposure to an outcome. One notable reason is that the OR has statistical properties that work well with logistic analysis, a popular statistical method (and the PR does not work as well). When the prevalence is rare, the OR will serve as a good approximation of the PR. When prevalence is common, the OR will overestimate the true PR. There are statistical methods that may be used with the PR. An example of the PR used in the medical literature can been found in the study by Iannotti et al (abstracted with a commentary by Dr Marion Roche), discussed in this edition of Current Best Evidence. APPLICATION/TRANSLATION PEARL: QUALITY AND MAGNITUDE OF THE EVIDENCE: “EBM is a systematic approach to clinical problem solving which allows the integration of the best available research evi- dence with clinical expertise and patient values.” 1 This is the classic David Sackett EBM definition, noting the 3 legs supporting EBM practice, the first of which is “. . .integration of the best available research evidence.” This “leg” presumes identifying a knowledge gap, developing a specific question (the answer to which will fill the gap), and the expertise, or access to expertise, to search for and critically appraise medical research studies. This last point, critical appraisal, is composed of 3 aspects: assessing the scientific validity of the study, interpretation of the results, and the level of evidence (eg, primary study, systematic review, synthesis, summary). While much focus has been placed in educational settings on understanding the basic EBM statistics (for interpretation of results), validity assessment is the primary force behind one’s confidence in the overall value of study. Each type of study (therapy, diagnosis, etc) has its own set of validity measures, satisfactory fulfillment of which fosters appropriate confidence to proceed with discerning the magnitude of the results. Critical appraisal is step one in applying/ translating research. The more confidence one has in the basic scientific validity and in the magnitude of the results, the more confidence one has in bringing research study results to the bedside. —Jordan Hupert, MD Reference 1. Sackett DL, Strauss SE, Richardson WS, Rosenberg W, Haynes RB. Evidence-based medicine: how to practice and teach EBM. London: Churchill- Livingstone; 2000. An egg a day enhances growth in resource- poor communities Iannotti LL, Lutter CK, Stewart CP, Gallegos Riofrío CA, Malo C, Reinhart G, et al. Eggs in Early Complementary Feeding and Child Growth: A Randomized Controlled Trial. Pediatrics 2017;140. pii: e20163459. Question Among children in resource-poor communities, what is the therapeutic efficacy of a daily supplemental egg, com- pared with usual diet, on enhancing growth? Design Randomized controlled trial. Setting Five rural parishes of the Cotopaxi Province in Ecuador. Participants Mother (caregiver)-infant pairs. Infants, 6-9 months, in good health. Intervention One egg a day for 6 months versus control (no supplemental eggs provided). Outcomes Linear and mass growth. Main Results There was a reduced prevalence of stunting by 47% (adjusted prevalence ratio [aPR], 0.53; 95% CI, 0.37-0.77) and underweight by 74% (aPR, 0.26; 95% CI, 0.10-0.70). Conclusions Daily egg ingestion in resource poor areas en- hances growth. Commentary Global efforts toward the World Health Assem- bly target to reduce stunting by 40% are currently off track, due to limited investment in implementation of effective public health interventions. 1,2 This randomized controlled trial of an intervention in which 1 egg was provided daily for THE JOURNAL OF PEDIATRICS • www.jpeds.com CURRENT BEST EVIDENCE 287