Christensen, Stephanie

AbstractBackgroundWe sought to evaluate the association between vitamin D deficiency and the severity of coronavirus disease 2019 (COVID‐19) infection.MethodsMultiple databases from 1 January 2019 to 3 December 2020 were searched for observational studies evaluating the association between vitamin D deficiency and severity of COVID‐19 infection. Independent reviewers selected studies and extracted data for the review. The main outcomes of interest were mortality, hospital admission, length of hospital stay and intensive care unit admission.ResultsSeventeen observational studies with 2756 patients were included in the analyses. Vitamin D deficiency was associated with significantly higher mortality (odds ratio [OR]: 2.47, 95% confidence interval [CI]: 1.50–4.05; 12 studies; hazard ratio [HR]: 4.11, 95% CI: 2.40–7.04; 3 studies), higher rates of hospital admissions (OR: 2.18, 95% CI: 1.48–3.21; 3 studies) and longer hospital stays (0.52 days; 95% CI: 0.25–0.80; 2 studies) as compared to nonvitamin D deficient status. Subgroup analyses based on different cut‐offs for defining vitamin D deficiency, study geographic locations and latitude also showed similar trends.ConclusionsVitamin D deficiency is associated with greater severity of COVID‐19 infection. Further studies are warranted to determine if vitamin D supplementation can decrease the severity of COVID‐19.

Abstract Background: Hereditary Hypophosphatemic Rickets with Hypercalciuria (HHRH) is a rare condition of phosphate wasting due to variants in the SLC34A3 gene, encoding the sodium-phosphate cotransporter 2c (NaPi2c) at the brush border of proximal renal tubular cells (1). While labs are characterized by low serum phosphorus, high 1,25 dihydroxyvitamin D and inappropriately high levels of urine phosphate and calcium, the presenting symptoms can vary widely. Little remains known about specific phenotype-genotype correlations, especially in children. Clinical Cases: We report three new cases of HHRH in an unrelated 12 year-old male, 9 year-old female and 14 year-old male. All three patients were found to have low serum phosphorus for age (2.9-3.2 mg/dL), normocalcemia (9.4-9.9 mg/dL), low to low-normal parathyroid hormone (7-15 pg/mL), elevated 1,25 dihydroxyvitamin D (91-178 pg/mL), and hypercalciuria (4.5-7.6 mg/kg/day). Urine phosphorus was inappropriately elevated given the degree of their hypophosphatemia. Despite having similar lab findings, however, their clinical presentations were varied. The 12 year-old male presented with lower extremity pain, which was previously ascribed to patellofemoral pain syndrome. He had no history of renal symptoms, though a renal ultrasound later identified stones bilaterally. Conversely, the 9 year-old female and 14 year-old male presented with recurrent urinary stones and no bone symptoms. Genetic analyses identified 4 novel SLC34A3 gene mutations. Of interest, the 12 year-old male and 9 year-old female each shared a variant (c.575C-T (p.Ser192Leu)) despite having disparate symptoms. All three patients were treated with phosphorus supplementation and were advised to discontinue Vitamin D, if this had previously been prescribed. Conclusion: These three cases highlight the variability of presenting signs and symptoms among individuals with HHRH. Obtaining an accurate diagnosis is critical, as the addition of Vitamin D can seriously worsen symptoms in HHRH though it is a commonly used treatment for other disorders of phosphate wasting and bone demineralization. To aid in clinical decision making, we present a stepwise approach to the diagnosis of hypophosphatemic diseases. References: (1) Lorenz-Depiereux, B., Benet-Pages, A., Eckstein, G., Tenenbaum-Rakover, Y., Wagenstaller, J., Tiosano, D., Gershoni-Baruch, R., Albers, N., Lichtner, P., Schnabel, D., Hochberg, Z., Strom, T. Hereditary Hypophosphatemic Rickets with Hypercalciuria is caused by mutations in the sodium-phosphate cotransporter gene SLC34A3. Am. J. Hum. Genetic. 2006;78:193-201.