Methods: This case-control study evaluated risk factors and outcomes associated with secondary S. aureus BSI among adult ABSSSI patients. Patients age ≥ 18 y with an ABSSSI diagnosis presenting to two academic medical centers in Detroit, MI from 2010 to 2015 were included. Baseline/clinical characteristics and outcomes were compared between cases (ABSSSI + BSI) and controls (ABSSSI). Outcomes included in-hospital mortality, hospital length of stay (los) and 30-day reinfection. Fisher’s exact and Student’s t or Mann-Whitney U tests were used for bivariate comparisons. Variables associated with ABSSSI + BSI in bivariate analysis at a p value < 0.1 were included in multivariable logistic regression to examine factors independently associated with ABSSSI + BSI.
Results: 392 patients consisting of 196 ABSSSI + BSI and 196 controls ABSSSI were evaluated. In bivariate analysis, individuals with ABSSSI + BSI were significantly older (p<0.001), more likely to be male (p = 0.008), be an intravenous drug user (p = 0.012), have chronic renal failure (p=0.002), prior hospitalization (p <0.001), and more systemic symptoms, such as elevated temperature, white blood cell count, and acute renal failure on hospital admission (p<0.001). By regression, male gender (aOR 1.85, 95% CI 11-3.66); acute renal failure (aOR 2.08, 95% CI 1.18-3.67); intravenous drug use (aOR 4.38, 95% CI 2.22-8.62); and prior hospitalization (aOR 2.41, 95% CI 1.24-4.93) remained statistically significant. ABSSSI + BSI patients were more likely to experience in-hospital mortality (4.1 vs. 0%, p <0.001), have longer mean los (7.4 ±5.7 vs. 2.7 ±2.2 days, p = <0.001), and experience 30-day reinfection (11.2 vs. 4.1%, p = 0.006).
Conclusion: Patients with ABSSSI + BSI had worse outcomes than those with ABSSSI alone. Factors associated with ABSSSI + BSI, such as gender, IVDU, prior hospitalization, renal failure, and systemic signs/symptoms of infection may be used to identify patients at risk for ABSSSI + BSI.
M. J. Rybak,
T. D. Trinh, None
A. M. Lagnf, None
V. Margaritis, None
A. B. Mendelsohn, None