Case fatality rate and survival functions of severe COVID-19 patients in intensive care unit of Bangabandhu Sheikh Mujib Medical University in Bangladesh: an observational study

Background: Emergence of current pandemic caused by novel SARS-COV-2 has already caused over 963000 deaths. Case fatality rate (CFR) estimation helps understanding the disease severity and the lethality trend, high risk population and subsequently, optimization of quality healthcare facilities. Our observational study aimed to find out existing trends in treating the most vulnerable group with scarce medical resource allocation and to implement necessary support services to comply with the ensuing need for best possible outcomes in our ICU. Methodology: In this observational study, all COVID-19 diagnosed patients admitted in our ICU from July 4, 2020 to September 22, 2020, were enrolled. Data were obtained from the core ICU register of Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh. Information accumulated on predesigned data sheets comprised of particulars of patients, co-morbidities, duration of ICU stay, mode of oxygenation, organ support and quick SOFA scores. Total deaths in ICU (in hospital or referred from outside of BSMMU) were recorded. Results: The results revealed that all patients were either very severe or critically sick with COVID-19 pneumonia at the time of ICU admission. Out of 174 patients, 46 (26.44%) were put on invasive ventilation and the rest received noninvasive ventilation in the form of NRM, high flow nasal cannula (HFNC), continuous positive airway pressure (CPAP or BiPAP), CTEX CPAP and non-invasive ventilation (NIV) as appropriate. Male and female ratio was 74:26. Age of patients ranged between 19-95y. The median age of patients was 65 y (IQR: 57-70).Quick SOFA scores were more than 2 in 65.37% of patients. Regarding co-existing organ dysfunction 13.8% had 3 or more co-morbidities;while 74.1% had 2 and 9.8% had a single systemic illness along with COVID-19. Most common diseases encountered among 135 deceased were hypertension (64%), IHD (49%), diabetes mellitus (45%), bronchial asthma or COPD (32%), renal failure (either ARF or CRF) (20%). Overall CFR due to COVID-19 pneumonia associated with co-morbidities was 77.6%. Relatively higher CFR (82.6%) was evident harboring multi-organ dysfunction especially among COVID-19 patients aged 50y or more. Gender linked CFR were 81.4% and 66.7% in males and females respectively. Conclusion: High CFR demonstrates significant correlation with increasing age and co-morbidities and survival functions. Late presentation to the hospital and invasive mechanical ventilation also contributed to high CFR.