Economic Consequences of Failure of Initial Antibiotic Therapy in Hospitalized Adults with Complicated Intra-Abdominal Infections

Background: Initial antibiotic therapy in hospitalized adults with complicated intra-abdominal infection (cIAI) usually is empiric. We explored the economic consequences of failure of such therapy in this patient population. Methods: Using a large U.S. multi-institutional database, we identified all hospitalized adults admitted between April 1, 2003, and March 31, 2004; who had any cIAI; underwent laparotomy, laparoscopy, or percutaneous drainage of an intra-abdominal abscess (surgery); and received intravenous (IV) antibiotics. Initial therapy was characterized in terms of all IV antibiotics received, on the day of or one day before initial surgery. Antibiotic failure was designated on the basis of the need for reoperation or receipt of other IV antibiotics postoperatively. Switches to narrower spectrum agents and changes in regimen prior to discharge with no other evidence of clinical failure were not counted as antibiotic failures. Using multivariable linear regression, duration of IV antibiotic therapy, hospital length of stay, and total inpatient charges were compared between patients who did and did not fail initial therapy. Mortality was compared using multivariable logistic regression. Results: Among 6,056 patients who met the study entrance criteria, 22.4% failed initial antibiotic therapy. Patients who failed received an additional 5.6 days of IV antibiotic therapy (10.4 total days [95% confidence interval 10.1, 10.8] days vs. 4.8 total days [4.8, 4.9] for those not failing), were hospitalized an additional 4.6 days (11.6 total days [11.3, 11.9] vs. 6.9 total days [6.8, 7.0], respectively), and incurred $6,368 in additional inpatient charges ($16,520 [$16,131, $16,919] vs. $10,152 [$10,027, $10,280]) (all, p < 0.01). They also were more likely to die in the hospital (9.5% vs. 1.3%; multivariable odds ratio 3.58 [95% confidence interval 2.53, 5.06]). Conclusions: Failure of initial IV antibiotic therapy in hospitalized adults with cIAIs is associated with longer hospitalization, higher hospital charges, and a higher mortality rate.