Temporal trend of microbiological profiles among patients with bloodstream infections: A comparison between cancer and noncancer patients in a nationwide database.

Abstract

e13078 Background: Bloodstream infection (BSI) is a leading cause of in-hospital mortality for cancer patients. Our goal is to describe the temporal trend of microbiological profiles and inpatient outcomes through a large national database. Methods: National Inpatient Sample is the largest U.S. database of hospitalized patients including 20% of patients from 4,378 hospitals. Hospitalizations of patients with BSI were identified by ICD-9 codes for bacteremia and fungemia from 2006-2014. 21 common microorganisms were identified by ICD-9-CM codes as the cause of BSI. We assessed the trend of incidence and mortality by linear regression and compared the in-hospital mortality between cancer and noncancer BSI patients by propensity score adjusted Cox proportional hazard model. Results: A total of 13,996,374 patients with BSI were identified (cancer 13.6%, noncancer 86.4%). Among cancer patients, gram positive bacteria (GPB) are the leading pathogens (27.38%), followed by gram negative bacteria (GNB) (23.59%), fungus (4.81%) and anaerobe (1.21%). Anaerobe had the fastest annual increase rate of incidence (16.54%), followed by GNB (15.77%), fungus (11.61%) and GPB (7.41%). Cancer patients had a faster increase rate of incidence than noncancer patients. The in-hospital mortality was highest for anaerobe (16.14%), followed by fungus (15.71%), GPB (13.65%) and GNB (12.14%). Except for fungal BSI, the mortality for other types of BSI decreased significantly. GNB had the most annual mortality decrease (-2.51%), followed by GPB (-2.48%) and anaerobe (-1.47%). Cancer patients had higher in-hospital mortality than noncancer patients (PS-matched HR 1.25, 95%CI: 1.24, 1.26), especially in GNB BSI (PS-matched HR 1.29, 95%CI: 1.27, 1.31). Using breast cancer patients as reference, lung cancer BSI patients had the worst relative mortality risk (1.65, 95%CI: 1.60, 1.69). Conclusions: The incidence of BSI increased steadily among cancer patients from 2006-2014, with GNB BSI increasing at the highest rate. Except for fungus, mortality of GNB, GPB and anaerobe decreased continually. Compared with noncancer patients, cancer patients had a larger increase in the incidence of all types of BSI, especially anaerobes, and higher mortality than noncancer patients. BSI in lung cancer patients was associated with the highest mortality rate.