HEPATITIS-C INFECTION RISK ANALYSIS - WHO SHOULD BE SCREENED - COMPARISON OF MULTIPLE SCREENING STRATEGIES BASED ON THE NATIONAL HEPATITIS SURVEILLANCE PROGRAM

Objectives: Hepatitis C, an infection of high prevalence worldwide, is insidiously progressive in many. Reduction of person-to-person spread is possible, and treatment is possible for many, particularly if offe red before cirrhosis develops. Screening for hepatitis C (HCV) would b e appropriate if strategies could be developed to afford adequate sens itivity and specificity at reasonable cost. We evaluated the performan ce characteristics of several screening strategies to determine the be st balance between cost and performance. Methods: The database of a na tional-hepatitis screening program was used to define risk factors for HCV. Features associated with increased risk for HCV by multivariable analysis were combined in various ways to construct HCV screening mod els. Screening Model 1 employed a mathematical model constructed to pr edict the probability of hepatitis C. Using this model, testing for HC V-was done if the probability of HCV was determined to be higher than 7%. Models 2 and 3 called for HCV testing if certain risk factors, str atified as socially intrusive, or nonintrusive in nature, were present . Model 4 calls for testing for HCV only when ALT values are elevated. Costs per case discovered were calculated for each model. Results: Ni ne thousand two-hundred sixty-nine individuals from a database of 13,9 97 has sufficient information to be included in the modeling studies. Risk factors considered socially intrusive were intravenous (IV) drug use and sex with an IV drug user. Risk factors considered not socially intrusive were: history of blood transfusion, age 30-49 yrs, and male gender. The sensitivity of Models 1-4 were 65%, 69%, 53%, and 63%, re spectively. Specificities were 84%, 74%, 77%, and 92%, respectively. T he cost per case detected was lowest when Models 1 or 2 were used ($35 7 and $439, respectively) and higher for models 3 and 4 ($487 and $104 7, respectively). Conclusions: The yield and cost of screening for HCV compares favorably with accepted current screening practices for othe r diseases. Models 1, 2, and 3 may be appropriate in certain clinical and epidemiological settings. Selective screening by a risk factor que stionnaire (first three models) is more cost-effective than blood test ing with ALT (Model 4). (C) 1998 by Am. Coll. of Gastroenterology.