Nosocomial COVID-19: A Nationwide Spanish Study

Abstract

<b><i>Introduction:</i></b> SARS-CoV-2 is a highly contagious virus, and despite professionals’ best efforts, nosocomial COVID-19 (NC) infections have been reported. This work aimed to describe differences in symptoms and outcomes between patients with NC and community-acquired COVID-19 (CAC) and to identify risk factors for severe outcomes among NC patients. <b><i>Methods:</i></b> This is a nationwide, retrospective, multicenter, observational study that analyzed patients hospitalized with confirmed COVID-19 in 150 Spanish hospitals (SEMI-COVID-19 Registry) from March 1, 2020, to April 30, 2021. NC was defined as patients admitted for non-COVID-19 diseases with a positive SARS-CoV-2 test on the fifth day of hospitalization or later. The primary outcome was 30-day in-hospital mortality (IHM). The secondary outcome was other COVID-19-related complications. A multivariable logistic regression analysis was performed. <b><i>Results:</i></b> Of the 23,219 patients hospitalized with COVID-19, 1,104 (4.8%) were NC. Compared to CAC patients, NC patients were older (median 76 vs. 69 years; <i>p</i> < 0.001), had more comorbidities (median Charlson Comorbidity Index 5 vs. 3; <i>p</i> < 0.001), were less symptomatic (<i>p</i> < 0.001), and had normal chest X-rays more frequently (30.8% vs. 12.5%, <i>p</i> < 0.001). After adjusting for sex, age, dependence, COVID-19 wave, and comorbidities, NC was associated with lower risk of moderate/severe acute respiratory distress syndrome (ARDS) (adjusted odds ratio [aOR]: 0.72; 95% confidence interval [CI]: 0.59–0.87; <i>p</i> < 0.001) and higher risk of acute heart failure (aOR: 1.40; 1.12–1.72; <i>p</i> = 0.003), sepsis (aOR: 1.73; 1.33–2.54; <i>p</i> < 0.001), and readmission (aOR: 1.35; 1.03–1.83; <i>p</i> = 0.028). NC was associated with a higher case fatality rate (39.1% vs. 19.2%) in all age groups. IHM was significantly higher among NC patients (aOR: 2.07; 1.81–2.68; <i>p</i> < 0.001). Risk factors for increased IHM in NC patients were age, moderate/severe dependence, malignancy, dyspnea, moderate/severe ARDS, multiple organ dysfunction syndrome, and shock; odynophagia was associated with lower IHM. <b><i>Conclusions:</i></b> NC is associated with greater mortality and complications compared to CAC. Hospital strategies to prevent NC must be strengthened.

Risk factors for nosocomial COVID-19 in a French university hospital

“…Nosocomial and community-acquired COVID-19 have been frequently compared in the literature. In our study, patients with nosocomial COVID-19 were older and had a longer hospital stay than patients with community-acquired COVID-19 as it was previously demonstrated in three other studies [4] , [28] , [29] . We identified a higher mortality in patients with nosocomial (36%) than in those with community-acquired COVID-19 (21%).…”

“…An observational study had similar results as ours for mortality of nosocomial cases (32%) but they identified a higher proportion of admissions to the ICU for patients with nosocomial compared with those with community-acquired COVID-19 [4] . Finally, we did not identify any difference regarding gender as found in the literature [28] , [29] , [32] .…”

Nosocomial COVID‐19 infection in the era of vaccination and antiviral therapy

“…Previous studies investigating nosocomial COVID-19 were largely performed before the availability of COVID-19 vaccination and effective antiviral therapies. [2][3][4][5] Reported rates of nosocomial COVID-19 cases vary between 5% and 17%. 4,5 The mortality rate of nosocomial COVID-19 in these studies ranged from 27% to 41%.…”

“…[2][3][4][5] Reported rates of nosocomial COVID-19 cases vary between 5% and 17%. 4,5 The mortality rate of nosocomial COVID-19 in these studies ranged from 27% to 41%. In the COPE-Nosocomial Study (COVID in Older People), conducted in early 2020, nosocomial COVID-19 infection was associated with a similar mortality rate compared with communityacquired infections, 2 whereas, in others, patients with nosocomial COVID-19 did worse.…”

“…In the COPE-Nosocomial Study (COVID in Older People), conducted in early 2020, nosocomial COVID-19 infection was associated with a similar mortality rate compared with communityacquired infections, 2 whereas, in others, patients with nosocomial COVID-19 did worse. [3][4][5] Since this time, the availability of antiviral therapy, preexisting immunity through both vaccination and prior infection and the emergence of the Omicron variant and sublineages associated with milder disease have made these findings difficult to generalise to current hospitalised patients. 6,7 In this context, new data regarding the outcome of nosocomial COVID-19 are warranted.…”