Clinical question: What is the in-hospital mortality risk associated with hospital-acquired Clostridium difficile infection after accounting for time to infection and baseline mortality risk at admission?
Background: Hospital-acquired C. diff infection (CDI) has been shown to be associated with a higher mortality rate and longer length of stay and cost. Previous studies have demonstrated an independent association of mortality with CDI, but have not incorporated time to infection and baseline mortality risk in the analyses.
Study design: Retrospective observational study.
Setting: Single-center, tertiary-care teaching hospital.
Synopsis: Patients who were hospitalized for more than three days were eligible. A baseline in-hospital mortality risk was estimated for each patient using an internally validated tool. A total of 136,877 admissions were identified. Mean baseline mortality risk was 1.8%. Overall rate of CDI was 1.02%.
Patients in the highest decile of baseline mortality risk had a higher rate of CDI than patients in the lowest decile (2.6% vs. 0.2%). Median time to diagnosis was 12 days. CDI was associated with an unadjusted fourfold higher risk of in-hospital death. When baseline mortality risk was included, the RR of death with CDI was 1.99 (95% CI 1.81-2.19).
Patients in the lowest decile of mortality risk had the highest risk of death (RR 45.70, 95% CI 11.35-183.98) compared with those in the highest decile (RR 1.29, 95% CI 1.11-1.50). Cox modeling estimated a threefold increase in death.
This study is limited by being single-site and the mortality risk model has not been validated externally. Results are also estimated from a small number of cases in the lower deciles.
Bottom line: CDI is associated with threefold higher in-hospital mortality. Patients with higher baseline mortality risk have a higher risk of CDI but have a lesser risk of dying compared with patients with lower baseline mortality risk. Hospitals should continue their efforts to reduce rates of CDI.
Citation: Oake N, Taljaard M, van Walraven C, Wilson K, Roth V, Forster AJ. The effect of hospital-acquired C. diff infection on in-hospital mortality. Arch Intern Med. 2010;170(20):1804-1810.
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