Results
Nine hundred and ninety-one patients were included in the study. The mean age was 61.640±17.003 and 544 (54.89%) and 447 (45.11%) of the patients were male and female, respectively. Four hundred and twenty-one patients (42.48%) received atorvastatin whereas five hundred and seventy (57.52%) did not. Of those who received atorvastatin, 169 (40.14%) were taking the medication prior to hospital admission and atorvastatin was initiated for the rest of the patients on the first day of hospital admission.
Regarding demographics, patients who received atorvastatin were older (P<0.001), but no significant differences were observed in gender distribution and BMI between the two groups. Considering comorbidities, except for diabetes and CKD which were more prevalent in patients who did not receive atorvastatin (P<0.001), others including hypertension(P<0.001), coronary artery disease (P<0.001), and malignancy (P=0.012) were significantly higher in the group of patients who received atorvastatin. From laboratory data collected at baseline, C reactive protein was significantly higher in the group of patients who received atorvastatin (P=0.040). Patients who did not receive atorvastatin had a higher baseline erythrocyte sedimentation rate, serum creatinine, and urea levels compared to those who did not. Except for hydroxychloroquine (P=0.005) and corticosteroids (P=0.007), there were no significant differences between the two groups in medications used to treat COVID-19. Baseline demographics, clinical and laboratory data are presented in Table 1 .
Based on the crude analysis, no significant differences observed in mortality rate between two groups (26.84% vs 25.09%, P=0.221). Patients who received atorvastatin had a significantly lower hospital length of stay (P<0.001). Also, this group had a lower but non-significant need for mechanical ventilation (P=0.563). Results for primary and secondary outcomes are represented in Table 2 .
In unadjusted COX proportional analysis, atorvastatin was associated with a decreased in-hospital mortality (0.820[0.639-1.054]) and need for mechanical ventilation (0.709[0.486-1.034]). Stepwise COX regression proportional hazard ration analysis revealed that atorvastatin is associated with reduced risk of in-hospital mortality (0.679[0.517-0.890]) and the need for mechanical ventilation (0.602[0.401-0.903]), independently. From demographics, age, obesity, coronary heart disease, and malignancy included in the multivariable analysis to evaluate the need for invasive mechanical ventilation. Also, utilization of beta-blockers, ACEIs/ARB, atorvastatin, corticosteroid, hydroxychloroquine, and lopinavir/ritonavir were analyzed. In the stepwise model for the analysis of survival, age, hypertension, coronary heart disease, malignancy, and medication i.e., beta-blockers, ACEIs/ARB, atorvastatin, corticosteroid, hydroxychloroquine, and lopinavir/ritonavir remained in the multivariable model. The Association of factors with mortality and the need for invasive mechanical ventilation in COX proportional analysis is represented in Table 3.