Comparison of Trends in Hospital-Onset Bloodstream Infections (HOBSIs) and Central Line Associated Bloodstream Infections (CLABSIs) across a Three-Hospital Health System in the COVID Era

ABSTRACT

Background. Hospital-onset bloodstream infection (HOBSI) incidence has been proposed as a complementary quality metric to central line-associated bloodstream infection (CLABSI) surveillance. Several recent studies have detailed increases in median HOBSI and CLABSI rates during the COVID-19 pandemic. We sought to understand trends in HOBSI and CLABSI rates at a single health system in the context of COVID-19. Methods. We conducted a retrospective analysis of HOBSIs and CLABSIs at a three-hospital health system from 2017 to 2021 (Figure 1). We compared counts, denominators, and demographic data for HOBSIs and CLABSIs between the prepandemic (1/1/2017-3/30/2020) and pandemic period (4/1/2020-12/31/2021) (Table 1). We applied Poisson or negative binomial regression models to estimate the monthly change in incidence of HO-BSI and CLABSI rates over the study period. Figure 1 Definitions applied for hospital-onset bloodstream infections (HO-BSIs) and central line-associated bloodstream infections (CLABSIs). Potentially contaminated blood cultures were identified by microbiology laboratory technicians as any set of blood culture in which a single bottle was positive for organisms typically considered as skin contaminants. Uncertain cases undergo secondary review by senior lab technicians. Table 1 Count, denominator, and device utilization ratio data for hospital-onset bloodstream infections (HO-BSIs) and central line-associated bloodstream infections (CLABSIs) Note that central line utilization increased upon regression analysis (p<0.001). Results. The median monthly HOBSI rate per 1,000 patient days increased from 1.0 in the pre-pandemic to 1.3 (p< 0.01) in the pandemic period, whereas the median monthly CLABSI rate per central line days was stable (1.01 to 0.88;p=0.1;Table 2). Our regression analysis found that monthly rates of HO-BSIs increased throughout the study, but the increase was not associated with the onset of the COVID-19 pandemic based on comparisons of model fit (Figure 2;Table 3). Despite an increase in central line utilization, regression modelling found no changes in monthly CLABSIs rates with respect to time and the COVID-19 pandemic. Incidence of HOBSIs and CLABSIs by common nosocomial organisms generally increased over this time period, though time to infection onset remained unchanged in our studied population (Table 2). Conclusion. HOBSIs rates did not correlate with CLABSI incidence across a three-hospital health system from 2017 and 2021, as rates of HOBSI increased but CLABSI rates remained flat. Our observed increase in HOBSI rates did not correlate with the onset of the COVID-19 pandemic, and caution should be used in modeling the effects of COVID-19 without time-trended analysis. Further evaluation is needed to understand the etiology, epidemiology, and preventability of HO-BSI.