Impact of infectious complications after elective surgery on hospital readmission and late deaths in the U.S. Medicare population

Abstract

Background and purpose: Whereas the negative impact of infectious complications (IC) during the index hospitalization after elective surgery is well established, the long-term ramifications of hospital-acquired post-operative infections are not well studied. This analysis evaluated the impact of a hospital-acquired IC after open abdominal vascular surgery on the readmission rate and the mortality rates 30 and 90 days after initial discharge.

Methods: Data from all hospitals in the United States that performed elective open abdominal vascular operations in the Medicare population from 2005 to 2007 were extracted from the national Medicare Provider Analysis and Review database. The cohort consisted of all patients undergoing open abdominal vascular operations, including aortic, iliac, and visceral procedures. The ICs evaluated were pneumonia, urinary tract infection (UTI), postoperative sepsis (sepsis), surgical site infection (SSI), and Clostridium difficile infection (CDI). Patients were categorized as either developing an IC during their initial hospitalization (Index+INF) or not developing an IC (No INF). The rates of 30-day readmission, 30-day IC, and 30- and 90-day mortality after the initial discharge were evaluated longitudinally and compared in patients with and without an IC.

Results: A total of 29,549 open abdominal vascular procedures were identified, and 4,016 patients (13.6%) developed an IC during their index hospitalization: Pneumonia (5.1% of the total), UTI (2.7%), sepsis (1.6%), SSI (1.4%), and CDI (0.6%). Additionally, 1.13% of patients developed pneumonia, UTI, SSI, or CDI complicated by sepsis. The hospital mortality rate during the initial hospitalization was 13.7% (Index+INF) versus 4.0% (No INF) (p<0.0002). Infectious processes (pneumonia, UTI, SSI, and CDI) complicated by sepsis had an in-hospital mortality rate significantly higher than patients having an IC alone (50.9% vs. 13.7%; p<0.002). The mortality rate 30 and 90 days after the initial discharge was significantly higher for Index+INF than for No INF (4.4% vs. 1.2% and 8.6% vs. 2.6%, respectively; p<0.0002). The highest 30-day mortality rates after discharge were found after CDI+sepsis (30%), pneumonia+sepsis (12.6%), and postoperative sepsis alone (8.6%). The same rank was found for the 90-day mortality rate: 30%, 22.5%, and 13.8%. Overall, readmission was more likely for Index+INF than for No INF (33.7% vs. 21.5%; p<0.0002). Rates of 30-day readmission after an index IC ranged from 32% to 50%.

Conclusion: For Medicare beneficiaries undergoing elective open abdominal vascular procedures, the development of any IC significantly increased not only the in-hospital mortality rate but also the mortality rates 30 and 90 days after discharge from the hospital. Index ICs also were associated with a higher 30-day readmission rate. Hospital-acquired infections have a profound late effect on outcomes after discharge. Future programs targeting high-risk patients may improve long-term survival and minimize readmissions.