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Secondary infections in patients hospitalized with COVID-19: incidence and predictive factors
Marco Ripa1, Laura Galli2, Andrea Poli2
1Unit of Infectious and Tropical Diseases, IRCCS San Raffaele Scientific Institute, Milan, Italy; Vita-Salute San Raffaele University, Milan, Italy.
Insights
Secondary infections are common in hospitalized coronavirus disease 2019 (COVID-19) patients. Risk factors include low lymphocyte counts, respiratory failure, and early intensive care unit (ICU) admission.
Area of Science:
- Infectious Diseases
- Critical Care Medicine
- Pulmonology
Background:
- Coronavirus disease 2019 (COVID-19) can lead to severe respiratory illness and increased susceptibility to secondary infections.
- Secondary infections pose a significant threat to hospitalized COVID-19 patients, potentially increasing morbidity and mortality.
Purpose of the Study:
- To determine the incidence of secondary infections in patients hospitalized with COVID-19.
- To identify predictive factors associated with the development of secondary infections in this patient population.
Main Methods:
- A cohort study was conducted involving 731 patients hospitalized with COVID-19.
- Secondary bloodstream infections (BSIs) and possible lower respiratory tract infections (pLRTIs) were assessed.
- Multivariable Fine-Gray models were used to analyze risk factors for secondary infections.
Main Results:
- A secondary infection was diagnosed in 9.3% of patients, with BSIs in 7.9% and pLRTIs in 3.0%.
- The 28-day cumulative incidence of secondary infections was 16.4%.
- Key risk factors identified included low baseline lymphocyte count, low PaO2/FiO2 ratio, and ICU admission within 48 hours.
Conclusions:
- Hospitalized COVID-19 patients experience a high incidence of secondary infections.
- Early intensive care unit (ICU) admission, respiratory failure, and severe lymphopenia are significant risk factors for secondary infections in COVID-19 patients.
Objectives:
The aim of our study was to describe the incidence and predictive factors of secondary infections in patients with coronavirus disease 2019 (COVID-19).
Methods:
This was a cohort study of patients hospitalized with COVID-19 at IRCCS San Raffaele Hospital between 25th February and 6th April 2020 (NCT04318366). We considered secondary bloodstream infections (BSIs) or possible lower respiratory tract infections (pLRTIs) occurring 48 hours after hospital admission until death or discharge. We calculated multivariable Fine-Gray models to assess factors associated with risk of secondary infections.
Results:
Among 731 patients, a secondary infection was diagnosed in 68 patients (9.3%); 58/731 patients (7.9%) had at least one BSI and 22/731 patients (3.0%) at least one pLRTI. The overall 28-day cumulative incidence was 16.4% (95%CI 12.4-21.0%). Most of the BSIs were due to Gram-positive pathogens (76/106 isolates, 71.7%), specifically coagulase-negative staphylococci (53/76, 69.7%), while among Gram-negatives (23/106, 21.7%) Acinetobacter baumanii (7/23, 30.4%) and Escherichia coli (5/23, 21.7%) predominated. pLRTIs were caused mainly by Gram-negative pathogens (14/26, 53.8%). Eleven patients were diagnosed with putative invasive aspergillosis. At multivariable analysis, factors associated with secondary infections were low baseline lymphocyte count (≤0.7 versus >0.7 per 109/L, subdistribution hazard ratios (sdHRs) 1.93, 95%CI 1.11-3.35), baseline PaO2/FiO2 (per 100 points lower: sdHRs 1.56, 95%CI 1.21-2.04), and intensive-care unit (ICU) admission in the first 48 hours (sdHR 2.51, 95%CI 1.04-6.05).
Conclusions:
Patients hospitalized with COVID-19 had a high incidence of secondary infections. At multivariable analysis, early need for ICU, respiratory failure, and severe lymphopenia were identified as risk factors for secondary infections.
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