Prognosis of left-sided infective endocarditis in patients transferred to a tertiary-care hospital--prospective analysis of referral bias and influence of inadequate antimicrobial treatment.

The aims of this study were to compare the characteristics of adult patients with left-sided infective endocarditis (LSIE) diagnosed and treated in a tertiary-care hospital with those of patients referred from a second-level community hospital, and to establish the accuracy of diagnosis and adequacy of treatment in referred patients and the influence of this factor on outcome. A prospective observational cohort study was conducted at Hospital Universitari Vall d'Hebron, a 1000-bed teaching hospital in Barcelona (Spain) and a referral centre for cardiac surgery. One hundred and fourteen of 337 (34%) episodes of LSIE treated in our hospital occurred in transferred patients. As compared with patients diagnosed in our hospital, transferred patients acquired LSIE within the healthcare system less often (16.7% vs. 38.1%, p <0.001), were in better health (Charlson index 3 (interquartile range (IQR)) 1-4) vs. 4 (IQR 2-6), p <0.001), had more complications (94.7% vs. 78.9%, p <0.001), underwent more operations (69.3% vs. 22.1%, p <0.001), and experienced similar mortality (22.8% vs. 31.4%, p 0.100). Only 52 of 114 (45.6%) referred patients received an antimicrobial regimen included in the American, European or Spanish guidelines at the hospital of origin. After adjustment for congestive heart failure and staphylococcal infection in multivariate logistic regression, inadequate or no antimicrobial treatment at origin was a risk factor for in-hospital mortality (OR 3.3, 95% CI 1.1-10.0, p 0.030). Errors in the initial antimicrobial treatment prescribed for LSIE are associated with greater mortality.