In-hospital mortality from severe COVID-19 in a tertiary care center in Mexico City; causes of death, risk factors and the impact of hospital saturation

Abstract

Background: As the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has remained in Latin America, Mexico has become the third country with the highest death rate worldwide. Data regarding in-hospital mortality and its risk factors, as well as the impact of hospital overcrowding in Latin America has not been thoroughly explored.

Methods and findings: In this prospective cohort study, we enrolled consecutive adult patients hospitalized with severe confirmed COVID-19 pneumonia at a SARS-CoV-2 referral center in Mexico City from February 26th, 2020, to June 5th, 2020. A total of 800 patients were admitted with confirmed diagnosis, mean age was 51.9 ± 13.9 years, 61% were males, 85% were either obese or overweight, 30% had hypertension and 26% type 2 diabetes. From those 800, 559 recovered (69.9%) and 241 died (30.1%). Among survivors, 101 (18%) received invasive mechanical ventilation (IMV) and 458 (82%) were managed outside the intensive care unit (ICU); mortality in the ICU was 49%. From the non-survivors, 45.6% (n = 110) did not receive full support due to lack of ICU bed availability. Within this subgroup the main cause of death was acute respiratory distress syndrome (ARDS) in 95% of the cases, whereas among the non-survivors who received full (n = 105) support the main cause of death was septic shock (45%) followed by ARDS (29%). The main risk factors associated with in-hospital death were male sex (RR 2.05, 95% CI 1.34-3.12), obesity (RR 1.62, 95% CI 1.14-2.32)-in particular morbid obesity (RR 3.38, 95%CI 1.63-7.00)-and oxygen saturation < 80% on admission (RR 4.8, 95%CI 3.26-7.31).

Conclusions: In this study we found similar in-hospital and ICU mortality, as well as risk factors for mortality, compared to previous reports. However, 45% of the patients who did not survive justified admission to ICU but did not receive IMV / ICU care due to the unavailability of ICU beds. Furthermore, mortality rate over time was mainly due to the availability of ICU beds, indirectly suggesting that overcrowding was one of the main factors that contributed to hospital mortality.

Fig 1. Flowchart of the study design.

Only the boxes with dashed lines were included in the risk factors analysis. SARS-CoV-2, severe acute respiratory syndrome coronavirus 2. ICU, intensive care unit. PCR, polymerase chain reaction. DNI/DNR, do not intubate/do not resuscitate. IMV, invasive mechanical ventilation. *These 7 patients died during CPR outside the ICU and did not received IMV.

Fig 2. Bar graph.

Panel A: Timeline of mortality during the course of the study divided by patients who received ICU/IMV/CPR support, those who were limited due to resource availability (NO IMV) and those who decided DNI/DNR status. Panel B: Timeline of mortality divided by hospitalization areas.