CDC data from 2012 indicated that 45% of HCV-infected people reported no known risk factors (RFs). However, initiating widespread, automated, RF-based screening outside the Birth Cohort (BC) (b. 1945-1965) is challenging as RFs are often unstructured, not searchable data within Electronic Health Records (EHR). Therefore, testing non-BC patients solely based on RFs has the potential to miss a substantial number of HCV infected patients.
In July 2015 HCV testing data was collected on non-BC patients who were HCV tested across MedStar Health, as a presumptive marker for high risk. A 1:3 case-control retrospective nested chart review was conducted. HCV RFs and opiate prescriptions were manually abstracted from the EHR; other variables were collected using Explorys. Univariate and multivariate logistic regression models were utilized to determine HCV Ab positive (Ab+) predictors.
Between 7/1/15 and 6/30/16, 329 charts out of 4,741 HCV tested non-BC patients were reviewed; 80 (1.7%) HCV Ab+ or indeterminate patients were compared to 249 randomly selected HCV Ab negative (Ab-) controls (see table for demographics). In bivariate analysis, patients with at least one documented RF were more than twice as likely to have Medicaid (p = 0.005) and more than three times as likely to have Medicare than patients without RFs (p = 0.0034). Eighteen (23%) HCV Ab+ and 123 (49%) HCV Ab- had no identified RFs; 6 (33%) HCV Ab+ reported RFs only after a positive test result. In multivariate logistic regression, persons were more likely to be HCV Ab+ if they: reported drug use (ORadj26, CI95 6.1-109.8), had Medicaid v. private insurance (3.4, 1.6-7.7), and were white v. other races (3.4, 1.5-7.9), adjusting for demographic factors and opiate prescriptions; sex behavior was no longer significant (ROC = 0.823). There was a significant interaction between age over 40 and opiate prescription use; these groups were 11x more likely to be HCV Ab+ (CI95 1.6-74.8).
In non-BC patients, drug use remained a significant predictor of HCV positivity, as in the BC. However, white race was more significant than black race, which is reversed compared to the BC. The CDC has reported an increase of HCV in opiate abusers, and our data shows some signal for increased risk as well. RF testing in non-BC patients has the potential to miss a significant number of HCV Ab+ patients. Given patient- and provider-level barriers in elucidating RFs, universal HCV Ab testing may be warranted.