Infections present on admission compared with hospital-acquired infections in acute ischemic stroke patients

Abstract

Background: To date, few studies have assessed the influence of infections present on admission (POA) compared with hospital-acquired infections (HAIs) on neurologic deterioration (ND) and other outcome measures in acute ischemic stroke (AIS).

Methods: Patients admitted with AIS to our stroke center (July 2010 to December 2010) were retrospectively assessed. The following infections were assessed: urinary tract infection, pneumonia, and bacteremia. Additional chart review was performed to determine whether the infection was POA or HAI. We assessed the relationship between infections in ischemic stroke patients and several outcome measures including ND and poor functional outcome. A mediation analysis was performed to assess the indirect effects of HAI, ND, and poor functional outcome.

Results: Of the 334 patients included in this study, 77 had any type of infection (23 POA). After adjusting for age, National Institutes of Health Stroke Scale at baseline, glucose on admission, and intravenous tissue plasminogen activator, HAI remained a significant predictor of ND (odds ratio [OR]=8.8, 95% confidence interval [CI]: 4.2-18.7, P<.0001) and poor functional outcome (OR=41.7, 95% CI: 5.2-337.9, P=.005), whereas infections POA were no longer associated with ND or poor functional outcome. In an adjusted analysis, we found that 57% of the effect from HAI infections on poor functional outcome is because of mediation through ND (P<.0001).

Conclusions: Our data suggests that HAI in AIS patients increases the odds of experiencing ND and subsequently increases the odds of being discharged with significant disability. This mediated effect suggests a preventable cause of ND that can thereby decrease the odds of poor functional outcomes after an AIS.

Keywords: Infection; acute cerebral infarction; health policy; ischemic stroke; outcomes research; stroke treatment.

Figure 1

(A) Crude association between timing of infection and neurologic deterioration. (B) Adjusted association between timing of infection and neurologic deterioration. (C) Crude association between timing of infection and poor functional outcome. (D) Adjusted association between timing of infection and poor functional outcome. Abbreviations: HAI, hospital-acquired infection; POA, present on admission. The diamond symbol signifies the odds ratio with the bands extending from it the 95% confidence intervals.