Cost-effectiveness of mandatory compared with voluntary screening for human immunodeficiency virus in pregnancy.

OBJECTIVE To determine the cost-effectiveness of mandatory screening for human immunodeficiency virus (HIV) in pregnancy compared with that of voluntary screening under varying assumptions about patient behavior. METHODS Using a health care system perspective, a decision-analysis model was constructed to estimate the outcomes and costs of the two strategies. Average and incremental cost-effectiveness ratios were calculated for each strategy. Sensitivity analyses were performed to test the effects of different values on the results of the simulation. In particular, we examined the potential effects of changes in patient behavior resulting from mandatory screening on our estimates of cost-effectiveness. RESULTS At a prevalence of 170 per 100,000, average costs per case prevented were $255,158 and $367,998 for mandatory and voluntary screening, respectively. The incremental cost-effectiveness of mandatory compared with voluntary screening was $29,478. These values decreased as prevalence of HIV increased, or as the estimated lifetime cost of pediatric HIV infection increased: above an estimated cost for pediatric HIV of $129,250, mandatory screening was less expensive and more effective than voluntary screening. Assumptions about patient behavior affected these results: a 40% reduction in zidovudine acceptance in women identified only through mandatory screening increased the incremental cost-effectiveness to $112,434. The impact of behavior increased as the prevalence of HIV increased. CONCLUSION Mandatory screening will prevent more cases of pediatric AIDS, but at a somewhat higher cost than voluntary screening under baseline assumptions. The cost-effectiveness of mandatory screening will be influenced by patient behavior, especially acceptance of zidovudine treatment among women who would have refused voluntary screening.