Serum IFN-γ and Electrolyte Dysregulation as Independent Predictors of COVID-19 Severity: A Cross-Sectional Study in Iraqi Patients

Abstract

COVID-19 pandemic has caused a significant mortality and morbidity in Iraq. Evidence is mounting that immune dysfunction and electrolyte derangements are key factors in disease progression and clinical outcome. The aim of this study was to assess the diagnostic utility of serum interferon gamma (IFN-gamma) along with electrolyte levels (potassium, sodium, chloride and calcium) as markers for the severity of the COVID-19 disease using ROC curve analysis. This cross-sectional study included 200 confirmed COVID-19 (severe, 100 patients; non-severe, 100 patients) admitted to Dar Al-Salam Hospital in Baghdad during January to December 2023. Severity was determined at admission according to the criteria set by the WHO. The level of serum IFN-gamma was measured by sandwich ELISA and electrolytes (Na, K, Ca and Cl) were estimated by biochemical assays with standard chemicals. Mann-Whitney U, chi-square, Spearman correlation, and ROC curve analyses were carried out using SPSS version 26 (IBM Corp., Chicago, IL, USA). Median serum IFN-gamma was significantly higher in non-severe patients than in severe patients (30.71 vs 7.81 pg/ml; P<0.001). Sodium levels were lower in severe cases (139.95 vs 146.80 mmol/L; P<0.001), while calcium was elevated (10.27 vs 9.37 mg/dL; P<0.001). Chloride and potassium were significantly higher in severe patients (P<0.001). ROC analysis demonstrated excellent discriminatory ability for IFN-gamma (AUC=0.917, 95% CI: 0.876-0.957), good ability for calcium (AUC=0.857) and chloride (AUC=0.848), and good ability for sodium (AUC=0.827). Potassium showed fair discriminatory ability (AUC=0.702), with elevated levels associated with disease severity. Elevated IFN-gamma in non-severe cases indicates its association with reduced inflammation and recovery, while low levels correlate with disease progression. Electrolyte imbalance plays a pivotal role in COVID-19 severity. IFN-gamma, calcium, and chloride demonstrate excellent to good predictive performance for disease severity.