Introduction: Previous studies of pediatric urolithiasis have suggested possible associations between the relative proportions of calcium oxalate dihydrate (COD) and calcium oxalate monohydrate (COM) stones with age, gender, and ethnicity. This study aimed to investigate the composition and distribution of calcium oxalate stones according to these clinical factors and the metabolic correlates of the different subtypes in pediatric stone formers. Patients and Methods: We retrospectively reviewed the database of all first-time stone formers between 2014 and 2019. Infrared spectrometry was used to determine stone composition. Stones were categorized by their highest relative component and reported as a percentage of occurrences in the cohort as a whole and by patient gender, age (divided into three age groups: 1-5, 6-12, 13-18 years), and ethnicity. Clinical and metabolic correlates were analyzed. Results: Of 2,479 consecutive stones submitted to our chemical stone lab, 220 first-time pediatric stone formers were identified. COD stones were the predominant subtype in the youngest group, and COM stones in the oldest group (OR 0.39, 95% CI:0.18-0.86, p=0.036). In the intermediate-age group (6-12 years), COM stones were more prevalent in Arab boys and COD stones in girls of either ethnicity. COD stones were associated with hypercalciuria (p< 0.0001), and COM stones with hyperoxaluria (p=0.0024). Hypercalciuria and hypocitraturia were the most prevalent abnormalities at ages 1-5 and 13-18, respectively. Conclusions: Analysis of calcium oxalate stone subtypes and their metabolic correlates in stone formers has significant clinical relevance, specifically in children. In the present study, COD stones and hypercalciuria were more common in younger children, and COM stones and hypocitraturia in adolescents. These findings suggest unique, complex interactions driving stone formations in children that may guide a more practical, limited, and cost-effective approach to metabolic evaluations, choice of treatment, and preventive measures, particularly in first-time calcium oxalate pediatric stone-formers.

The results of clinical lab tests are an essential component of medical decision-making. To guide interpretation, test results are returned with reference intervals defined by the range in which 95% of values occur in healthy individuals. Clinical laboratories often set their own reference intervals to accommodate local population and instruments variations. This approach is costly and can be biased. We describe a novel data-driven method for using electronic health record data to extract healthy patients’ information to define reference intervals. We found that the distributions of many clinical lab tests differ among self-identified racial and ethnic groups (SIREs) in healthy patients. Finally, we derived SIRE-specific reference intervals and provide evidence that these intervals have clinical prognostic value. Specifically, we show that for two lab tests, serum creatinine level and hemoglobin A1C, SIRE-specific reference intervals are more predictive for need for dialysis and development type 2 diabetes than existing reference intervals. One Sentence Summary: A novel method for defining population-specific reference intervals of common clinical laboratory tests from electronical health records has better prognostic value than existing reference intervals.

(1) Background: patients who meet current rapid rule-out criteria for myocardial infarction (MI) are considered low risk, yet their management remains nebulous, especially among women. We aimed to examine sex differences in the diagnosis, management, and outcomes of patients meeting the rapid rule-out criteria. (2) Methods: by simulating application of the rapid rule-out MI criteria, we analyzed consecutively triaged men and women with suspected NSTE-ACS who had high-sensitivity cardiac troponin T (hs-cTnT) values that met criteria (n = 11,477), in particular, those who were admitted (n = 3775). (3) Results: men constituted ~55% of triaged patients who met the rule-out criteria, whether admitted or discharged. Men were more likely to be admitted (33.7% vs. 31.9%, p = 0.04), more commonly with hs-cTnT values between level of detection (LOD, 5 ng/ml) and the 99th percentile (59.4% of all admissions vs. 40.5% for women), whereas women were more likely to be admitted with values < level of blank (LOB, 3 ng/mL; 22.9% vs. 9.2% for men). Thirty-day mortality (1 man and 1 woman) and in-hospital MI (9 men vs. 1 woman) were uncommon among admitted patients, yet resource utilization during 3–4 hospitalization days was substantial for both sexes, with men undergoing coronary angiography (6.8% vs. 2.9%) and revascularization (3.4% vs. 1.1%) more commonly. Long-term survival for both men and women, whether admitted or discharged, was significantly worse for hs-cTnT values between LOD and the 99th percentile, even after adjusting for age and cardiovascular comorbidities. (4) Conclusions: reporting actual hs-cTnT values < 99th percentile allows for better risk stratification, especially for women, possibly closing the sex gap.