Hospital-acquired infections in hospitalized patients with acute kidney injury: a retrospective cohort study

Abstract Background and Aims Acute kidney injury (AKI) is recognized as a systemic disease that leads to several complications, including infections. However, only few studies have investigated the relationship between AKI and subsequent development of hospital-acquired infections (HAI). The aim of this study was to evaluate this relationship. Method Retrospective cohort study, analyzing data of 413 hospitalized adult patients. Immunosuppressed patients have been excluded. Descriptive analysis was done with t-test, Mann-Whitney and Fisher test. Mediation analysis was done modelling time-to-HAI through a Cox regression, including AKI as the exposure of interest, the use of medical devices as mediator, and age, diabetes and multimorbidity as confounders. Results Clinical characteristics of patients are shown in Table 1. AKI patients resulted more fragile and with a higher frequency of HAI (10.8% vs 5.9%, p = 0.07). Univariate logistic regression showed that the presence of urinary catheter (OR 5.053, 95% CI 2.040-12.520) and a longer hospital stay (OR 1.115, 95% CI 1.075-1.157) were risk factors for the development of HAI. Compared to other AKI etiologies, intrinsic AKI had a significantly higher frequency of HAI (38.5%, p<0.01) (Fig. 1). HAI frequency also increased progressively with increasing AKI stage (15.2% in stage I-II and 6.4% patients without AKI or stage I, p = 0.01) (Fig. 1). From the Cox regression model, none of the variables showed an independent association with HAI (Table 2). The total effect of AKI on HAI development was estimated in a HR of 0.970 (95% CI 0.438-3.016). Part of this effect was found to be mediated by the medical devices (HR 1.155, 95% CI 0.982-1.393), while the direct effect of AKI was a HR of 0.840 (95% CI 0.352-2.411). Conclusion AKI patients are more fragile and have a higher frequency of HAIs, especially in intrinsic and stage II-III AKI. However, we didn't observe an independent effect of AKI on the development of HAIs. Further research is needed.