Table shows summary statistics for HAI and CAI, demonstrating that patients with resistant infections had considerably higher charges, days in the hospital, and likelihood of death compared to those with susceptible infections. However, patients with resistant infections also appeared to be higher-risk patients prior to the onset of the infection, as evidenced by higher Charlson comorbidity score, for example. Furthermore, patients with resistant HAI generally had more procedures done and higher charges prior to the onset of the infection, highlighting the importance of controlling for these risk factors.
Characteristics of Patients With Healthcare-Associated and Community-Associated Infections
Table presents the main estimates of the difference in postinfection charges, length of stay, and death from having a resistant HAI relative to a sensitive HAI. In a simple mean comparison without adjusting for risk factors, patients with resistant infections experienced a statistically significant increase in charges of >$70 000, length of stay of 7 days, and probability of death of 0.11. These estimates, however, do not account for the fact that patients with more resistant infections may be more likely to experience worse outcomes for other reasons. The next column shows linear regression results that adjusted for the confounding variables described above; the estimates become much smaller and, in some cases, statistically insignificant. Patients with resistant infections experienced roughly $8000 more in charges and just over 1 extra day in the hospital, though these differences are not statistically significant. In the next column, which uses nearest neighbor matching based on the propensity score, estimates are slightly larger than those from the linear model, and now statistically significant for charges.
Regression Estimates of the Difference in Hospital Charges, Hospital Stay, and Death Between Those With Antimicrobial-Resistant and -Susceptible Healthcare-Associated Infections
The results presented so far do not account for the fact that the outcomes of patients who die in the hospital are by definition censored. The next panel in Table repeats the same set of results but using censored models, and the results become much larger and more likely to be statistically significant. For example, the linear regression results suggest that patients with resistant infections experienced charges that were >$15 000 higher and stayed almost 2 days longer than patients with sensitive infections, with both estimates statistically significant. The propensity score estimates are again slightly larger than the linear regression estimates.
Table shows the same set of results as Table except it focuses on CAI. The results generally show a similar pattern as in Table , with adjusted estimates smaller than the unadjusted estimates, propensity score estimates slightly larger than the linear regression estimates (though estimates in the linear model are now statistically significant), and censored estimates larger than uncensored estimates. The impact of resistant infection on charges and length of stay is generally larger for CAI compared to HAI. For example, in the linear censored model, patients with resistant infections experienced additional charges of nearly $31 000 and slightly more than 3.5 extra days in the hospital, both roughly twice as large as the HAI estimates.
Regression Estimates of the Difference in Hospital Charges, Hospital Stay, and Death Between Those With Antimicrobial-Resistant and -Susceptible Community-Acquired Infections
Table shows estimates by type of organism and body site for HAIs, focusing only on the models that use linear adjustment for covariates. In the uncensored models, none of the resistant infections caused by specific organisms or body site were associated with significantly greater charges or length of stay, except for charges for vancomycin-resistant Enterococcus (VRE). Death rates were significantly higher for HAI caused by resistant Enterococcus species or K. pneumoniae as well as pneumonia and UTI. Estimates from censored models yield statistically significantly higher charges and length of stay for resistant infections for Enterococcus species, K. pneumoniae, pneumonia, and UTI.
Regression Estimates of the Difference in Hospital Charges, Hospital Stay, and Death Between Those With Antimicrobial-Resistant and -Susceptible Healthcare-Associated Infections by Type of Organism and Body Site
Table shows analogous results for CAI. Excess charges for CAI VRE infections were particularly high—$69 100 higher than sensitive Enterococcus infections. Patients with community-associated BSI or UTI with a resistant strain also had significantly higher charges. Length of stay was significantly longer for patients infected with resistant Enterococcus species, P. aeruginosa, and UTI as well, and probability of death was significantly higher for resistant BSI. Censored estimates are again considerably higher and more precise, though there is generally no difference in statistical significance.
Regression Estimates of the Difference in Hospital Charges, Hospital Stay, and Death Between Those With Antimicrobial-Resistant and -Susceptible Community-Associated Infections by Type of Organism and Body Site