HCV Risk in Patients with and without Serious Mental Illness: A National Analysis

Background: Although individuals with serious mental illness (SMI) are reported to have a high prevalence of Hepatitis C Virus (HCV), the results of these studies may be limited by non-representative, convenience samples, and lack of a non-SMI control groups. Methods: A cross-sectional study of patients in the Veterans Affairs (VA) health system who received at least 3 health care encounters during fiscal year 2002, comparing those with a diagnosis of schizophrenia or bipolar disorder (N=155,172) to a random sample of patients without these diagnoses (N = 67,965). Crude and adjusted logistic regression analyses evaluated the prevalence and predictors of HCV. Results: HCV was diagnosed in 7.1% of patients with schizophrenia, 8.1% of those with bipolar disorder, and 2.5% among patients with neither condition. We found a significant interaction between substance use and SMI diagnosis. Compared to patients without SMI, individuals with schizophrenia and co-occurring substance abuse had 6 times the odds of having a diagnosis of HCV, and those with bipolar disorder and co-occurring substance abuse had 7 times the odds. Even in the absence of substance abuse, diagnosis of schizophrenia and of bipolar disorder were associated with 40% and 60% greater odds of HCV, respectively. Those with bipolar disorder and substance use were significantly more likely to have HCV than those with schizophrenia and substance use. Conclusions: Substance abuse is a significant moderator of risks of HCV among patients with schizophrenia and with bipolar disorder. Improving substance abuse treatment and primary and secondary HCV prevention remains a critical goal.