About 80% of patients with hepatitis C virus (HCV) antibodies may be missed when risk-based testing is used in the primary care setting, according to researchers from the CDC.
In a retrospective study, Smith and colleagues analyzed electronic medical record data of patients ages 18 and older who presented to an outpatient primary care service between 2005 and 2010 and were never diagnosed with HCV. The purpose of the study was to determine the prevalence of HCV antibody positivity (anti-HCV+) and how many cases remained unidentified when a risk-based screening protocol was used.
Over a period of five months, researchers observed 209,076 patients. Of the 17,464 patients who were tested for anti-HCV, 6.4% were positive. Factors associated with anti-HCV+ included a history of injection drug use (adjusted odds ratio [aOR], 6.3), birth year of 1945-1965 (aOR, 4.4), and elevated alanine aminotransferase levels (aOR, 4.8). The researchers then used multiple imputation to assign anti-HCV+ results to untested patients, estimating that 81.5% of anti-HCV+ cases were unidentified.
Without knowing their status, patients with unidentified anti-HCV+ cannot receive additional evaluation or treatment and are therefore unlikely to benefit from prevention strategies that would reduce disease progression and ultimately mortality risk. Brown and colleagues concluded that baby boomers should be routinely tested for HCV “without the need for prior ascertainment of risk factors.”
The study results were published in Clinician Infectious Diseases.