CJEM Articles: surveillance

Objectives: This study was designed to determine the prevalence of HIV and hepatitis C virus (HCV) in a specific population, and to distinguish between known and previously unrecognized infections in the emergency department (ED) setting.
Methods: Consecutive patients aged 15 to 54 years who had presented to the EDs of 2 urban hospitals during a 6-week period were enrolled in a prospective cross-sectional study if a complete blood count had been obtained as part of their care. The study patients were initially cross-referenced against local databases of known HIV and HCV seropositive patients. After removal of all personal identifiers, the study patients' leftover blood was serotested for HIV and HCV, and seroprevalences were calculated. Univariate and multivariate analyses were performed to identify factors associated with HIV and HCV infection.
Results: Of 3057 individuals whose files were analyzed, 1457 (48%) were male and 7% (213) were Aboriginal. Overall, 302 patients (10%; 95% confidence interval [CI], 9%-11%) were seropositive for HCV and, of these, only 132 (44%) were previously known to be. HCV seropositivity was associated with Aboriginal status, age, male gender, hospital site and HIV infection (all p < 0.001). In contrast, 39 patients (1%; 95% CI, 1%-2%) were HIV seropositive. Of these, 32 (82%) were previously known to be HIV positive, and 27 (69%) were HCV seropositive. HIV seropositivity was only associated with HCV infection (p < 0.001).
Conclusions: The rate of previously undetected infections was relatively low for HIV but high for HCV. Emergency physicians in urban settings will frequently encounter patients not known to be HCV positive and not identified as such. These results emphasize the need for more effective preventive measures in the community and the importance of observing standard (universal) precautions in ED practice.