Abstract: BRIEF RESEARCH REPORT published: 07 January 2021 doi: 10.3389/fmed.2020.590805 High Prevalence of Hypocalcemia in Non-severe COVID-19 Patients: A Retrospective Case-Control Study Rimesh Pal 1 , Sant Ram 2*, Deepy Zohmangaihi 2 , Indranil Biswas 3 , Vikas Suri 4 , Laxmi N. Yaddanapudi 3 , Pankaj Malhotra 4 , Shiv L. Soni 3 , Goverdhan D. Puri 3 , Ashish Bhalla 4 and Sanjay K. Bhadada 1* 1 Department of Endocrinology, Post Graduate Institute of Medical Education and Research, Chandigarh, India, 2 Department of Biochemistry, Post Graduate Institute of Medical Education and Research, Chandigarh, India, 3 Department of Anesthesiology, Post Graduate Institute of Medical Education and Research, Chandigarh, India, 4 Department of Internal Medicine, Post Graduate Institute of Medical Education and Research, Chandigarh, India Edited by: Giacomina Brunetti, University of Bari Aldo Moro, Italy Reviewed by: Luigi Gennari, University of Siena, Italy Sudhaker D. Rao, Henry Ford Hospital, United States *Correspondence: Sanjay K. Bhadada bhadadask@rediffmail.com Sant Ram drsantram2016@gmail.com Specialty section: This article was submitted to Infectious Diseases - Surveillance, Prevention and Treatment, a section of the journal Frontiers in Medicine Received: 03 August 2020 Accepted: 09 December 2020 Published: 07 January 2021 Citation: Pal R, Ram S, Zohmangaihi D, Biswas I, Suri V, Yaddanapudi LN, Malhotra P, Soni SL, Puri GD, Bhalla A and Bhadada SK (2021) High Prevalence of Hypocalcemia in Non-severe COVID-19 Patients: A Retrospective Case-Control Study. Front. Med. 7:590805. doi: 10.3389/fmed.2020.590805 Frontiers in Medicine | www.frontiersin.org Purpose: To compare serum total calcium and phosphate levels in patients with non-severe COVID-19 with age, sex, and serum 25-hydroxyvitamin D level matched healthy adult cohort. Methods: In this retrospective case-control study, medical records of patients (≥18 years) diagnosed as non-severe COVID-19 admitted at and discharged from our tertiary care institution during the period from April 10, 2020 and June 20, 2020 were retrieved. Baseline investigations, notably, serum calcium, phosphate, albumin, magnesium, 25-hydroxyvitamin D, and C-reactive protein (CRP), were performed at admission before any form of calcium or vitamin D supplementation were considered. The biochemical parameters were compared with age, sex, and 25-hydroxyvitamin D matched healthy adult controls (1:1 ratio) derived from the Chandigarh Urban Bone Epidemiological Study (CUBES). Results: After exclusion, 72 patients with non-severe COVID-19 (63 mild and 9 moderate disease) and an equal number of healthy controls were included in the final analysis. Age, sex, serum 25-hydroxyvitamin D, and albumin levels were matched between the 2 groups. Hypovitaminosis D and hypocalcemia were seen in 97 and 67% of the patients, respectively. The patients had lower serum calcium (P value <0.001) and phosphate (P = 0.007) compared with the controls. There was no statistically significant correlation between serum calcium and CRP. Conclusions: Hypocalcemia is highly prevalent even in COVID-19 patients with non-severe disease probably implying that hypocalcemia is intrinsic to the disease. Prospective studies with larger number of patients are required to prove this hypothesis and unravel the underlying pathophysiological mechanisms. Keywords: COVID-19, calcium, hypocalcemia, hypovitaminosis D, vitamin D 1 January 2021 | Volume 7 | Article..