November 2007

Document Type


Degree Name



Dept. of Public Health and Preventive Medicine


Oregon Health & Science University


Background: About 2 million cases of Healthcare Acquired Infections (HAI) occur in hospitals each year, causing approximately 90,000 deaths and generating $4.5 billion in excess medical expenses. HAI complicate medical care causing worse clinical outcomes, extended hospital stays, and higher rates of mortality. Identifying adverse events due to medical care and the excess costs associated with them, along with designing interventions to decrease their prevalence, may offer a chance to redirect increasingly scarce healthcare dollars to more productive purposes. Specific Aims: Identify cases of HAI in Oregon hospital discharge data; estimate statewide costs associated with cases of HAI; and determine if severity of illness or comorbid conditions are important predictors of estimated costs per case of HAI. Study Design: Cross-sectional secondary analysis of hospital discharge data. Human Subjects: Adult Oregonians treated in Oregon hospitals who were at risk of developing an HAI during calendar years 2003, 2004, and 2005. Methods: The outcomes of interest were diagnosis of an HAI in the discharge record and the estimated costs per discharge. Cost-to-charge ratios for each hospital were estimated from audited financial statements. Costs per discharge were estimated from total charges multiplied by the hospital-specific cost-to-charge ratio and adjusted for inflation to 2005 dollars. Estimated costs per discharge for patients with HAI were compared to estimated costs per discharge for patients without HAI. Regression modeling was used to assess whether severity of illness or comorbidities are important predictors of estimated costs per discharge. Results: 1034 prevalent cases of HAI were identified. Costs per discharge averaged over $20,000 higher for patients with HAI compared to patients without HAI. The statewide excess costs were estimated to be at least $21 million, or approximately $7 million per year. Presence of an HAI, severity of illness, presence of a severe comorbidity, and surgical DRG were important predictors of estimated cost per discharge. Conclusions: HAI cases in Oregon hospitals are common, the statewide excess costs are substantial, and the excess costs are not fully explained by severity of illness or severe comorbidities.




School of Medicine



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