This retrospective cohort study aims to describe the clinical characteristics and outcomes and assess risk factors for mortality across the epidemic waves in hospitalized COVID-19 patients in a major tertiary-care center in Pakistan. A total of 5368 patients with COVID-19, hospitalized between March 2020 and April 2022 were included. The median age was 58 years (IQR: 44-69), 41% were females, and the overall mortality was 12%. Comparative analysis of COVID-19 waves showed that the proportion of patients aged ≥ 60 years was highest during the post-wave 4 period (61.4%) and Wave 4 (Delta) (50%) (p < 0.001). Male predominance decreased from 65.2% in Wave 2 to 44.2% in Wave 5 (Omicron) (p < 0.001). Mortality rate was lowest at 9.4% in wave 5 and highest at 21.6% in the post-wave 4 period (p = 0.041). In multivariable analysis for risk factors of mortality, acute respiratory distress syndrome (ARDS) was most strongly associated with mortality (aOR 22.98, 95% CI 15.28-34.55, p < 0.001), followed by need for mechanical ventilation (aOR 6.81, 95% CI 5.13-9.05, p < 0.001). Other significant risk factors included acute kidney injury (aOR 3.05, 95% CI 2.38-3.91, p < 0.001), stroke (aOR 2.40, 95% CI 1.26-4.60, p = 0.008), pulmonary embolism (OR 2.07, 95% CI 1.28-3.35, p = 0.003), and age ≥ 60 years (aOR 2.45, 95% CI 1.95-3.09, p < 0.001). Enoxaparin use was associated with lower mortality odds (aOR 0.45, 95% CI 0.35-0.60, p < 0.001. Patients hospitalized during Wave 4 (aOR 2.22, 95% CI 1.39-3.56, p < 0.001) and the post-wave 4 period (aOR 2.82, 95% CI 1.37-5.80, p = 0.005) had higher mortality odds compared to other waves. The study identifies higher mortality risk in patients admitted in Delta wave and post-wave, aged ≥ 60 years, and with respiratory and renal complications, and lower risk with anticoagulation during COVID-19 waves.
Keywords: COVID-19; Epidemic waves; Mechanical ventilation; Mortality.
© 2024. The Author(s).