Determinants of Severity of illness
Patients were classified as having asymptomatic/mild disease in 35%, moderate in 34%, or severe/critical disease in 30% based on WHO criteria. Mean age was significantly higher in patients with severe disease (59 years) compared to mild (42 years) and there was a male preponderance throughout all the levels of severity of illness. The presence of comorbidities such as diabetes, hypertension, and ischemic heart disease was greater in those with severe disease compared to patients with mild and moderate disease (p-value <0.001). A greater proportion of patients with severe disease had shortness of breath (83%) on presentation. Chest radiographic findings were bilateral patchy infiltrates in the majority of patients with moderate (87.5%) and severe disease (92%) whereas the majority of mildly diseased patients (60%) had a normal chest x-ray. Patients with greater severity of illness had significantly higher median CRP, Ferritin, LDH, and D-Dimer values as well as mean neutrophil to lymphocyte ratio compared to those with mild and moderate disease (p-value <0.001). Most patients received supplemental oxygen in moderate and severe disease (88% and 98.5% respectively). Steroids were used in the majority of patients with moderate and severe disease (79% and 90% respectively). Tocilizumab was given to 86 (19.3%) of cases and predominantly in those with severe disease, where almost half (47.4%) received this. Antibiotic use was common in severe disease with 91% receiving any antibiotics as opposed to16.5 of the mild and 57% of moderate cases. Ordinal logistic regression was performed to determine predictors of severity (Table 2). Multivariable ordinal regression analysis revealed that the risk of having severe disease was 1.92 (95% CI: 1.23 -3.03) times higher in patients with age greater than or equal to 60 years of age when compared with patients of less than 60 years. Presence of shortness of breath at presentation (OR=4.43; 95% CI: 2.73-7.22) and presence of bilateral patchy infiltrates on chest radiograph (OR=5.81; 95% CI: 2.90-11.62) was significantly associated with greater severity of illness. Among laboratory investigations done at admission; the risk of greater severity of illness was associated with CRP of greater than or equal to 150mg/L (OR=1.77; 95% CI: 1.10-2.85), LDH of greater than or equal to 500 I.U/L (OR=1.98; 95% CI: 1.25-3.16), Neutrophil to Lymphocyte ratio greater than or equal to 5 (OR=2.80; 95% CI: 1.77-4.42)and unit increase in serum creatinine level in mg/dl (OR=1.32; 95% CI: 1.07-1.61).