Prevalence of secondary infections and association with mortality rates of hospitalized COVID-19 patients.

Background: ICU and other patients hospitalized with corona-virus disease 2019 (COVID-19) are more susceptible to secondary infections. Undetected secondary infections tend to have a severe clinical impact, associated with prolonged hospitalization and higher rates of inpatient mortality.

Objectives: Estimate the prevalence of secondary infections, determine the frequency of microbial species detected at different body sites, and measure the association between secondary infections and outcomes among hospitalized COVID-19 patients.

Design: Cross-sectional analytical study.

Setting: Tertiary care center in Riyadh PATIENTS AND METHODS: Data were collected through retrospective chart review of hospitalized COVID-19 patients >18 years old from March 2020 until May 2022 at King Saud University Medical City (27 months). Rates of secondary infections among hospitalized COVID-19 patients were described and data on clinical outcomes (intensive care admission, invasive management procedures and mortality) was collected.

Main outcome measures: Features and rates of infection and mortality.

Sample size: 260 RESULTS: In total, 24.2% of the study population had secondary infections. However, only 68.8% of patients had secondary infection testing, from which 35.2% had a confirmed secondary infection. These patients had a significantly higher prevalence of diabetes mellitus (P<.0001) and cardiovascular diseases (P=.001). The odds of ICU admissions (63.3%) among secondarily infected patients was 8.4 times higher compared to patients with only COVID-19 infection (17.3%). Secondarily infected patients were more likely to receive invasive procedures (OR=5.068) and had a longer duration of hospital stay compared to COVID-19 only patients. Overall mortality was 16.2%, with a predominantly higher proportion among those secondarily infected (47.6% vs 6.1%) (OR=14.015). Bacteria were the most commonly isolated organisms, primarily from blood (23.3%), followed by fungal isolates, which were mostly detected in urine (17.2%). The most detected organism was Candida albicans (17.2%), followed by Escherichia coli (9.2%), Klebsiella pneumoniae (9.2%) and Pseudomonas aeruginosa (9.2%).

Conclusion: Secondary infections were prevalent among hospitalized COVID-19 patients. Secondarily infected patients had longer hospital stay, higher odds of ICU admission, mortality, and invasive procedures.

Limitation: Single-center study, retrospective design and small sample size.

Conflict of interest: None.