Correlation of Serum Calcium with Severity and Outcomes in Patients of COVID-19 Pneumonia

ABSTRACT Calcium is an essential electrolyte with critical physiological functions. Recently, it has been implicated in the pathogenesis and outcomes of COVID-19. This retrospective study was conducted to estimate serum ionic calcium and its correlation with clinical severity, inflammatory markers, and in-hospital outcomes in moderate to severe COVID-19 patients. We retrospectively analyzed data from 377 COVID-19 patients, aged between 23 and 79 years, with a mean age of 54.17±11.53 years. Severity of the disease was determined using ICMR criteria. Parameters including age, gender, inflammatory markers, calcium levels, and clinical outcomes were assessed. The study showed a prevalence of moderate and severe COVID-19 in 58.1% and 41.9% patients, respectively. Severity was significantly associated with younger age, higher mean inflammatory markers, notably IL-6, procalcitonin, D-Dimer, and lower ionic and total calcium levels, as well as vitamin D levels. Mortality and referral rate were significantly higher in the severe group. Hypocalcemia was prevalent in 39% of the patients and was significantly associated with disease severity, ARDS, and mortality. On multivariate assessment, only age and ionic calcium were significantly associated with COVID-19 severity. Lower serum ionic calcium levels are associated with increased severity and poor outcomes, including higher mortality in COVID-19 patients, underscoring the potential role of calcium as a diagnostic and prognostic marker in COVID-19 pneumonia and may be an important factor in various other forms of pneumonia.