Clinical preventive services efficacy and adolescents' risky behaviors.

OBJECTIVE/
BACKGROUND: To analyze the value of studying or implementing office-based clinical preventive services for adolescents. Most adolescent mortality and morbidity is attributable to risky behaviors, yet clinical preventive services to reduce risky behaviors are often challenged because their efficacy has not been demonstrated.
DESIGN: A cost-effectiveness model of adolescents' risky behaviors that compares standard practice with a program of screening visits for all adolescents and counseling visits for youth identified as high risk. We considered two risky behaviors, alcohol abuse and unsafe sexual activity, and five outcomes. MAIN OUTCOME MEASURES: Baseline cost-effectiveness of the program, minimum efficacy at which the program would be cost-effective, and sample sizes required for a trial of the program.
RESULTS: Assuming that the program is 5% effective at preventing risky behaviors, it would cost $3035 to prevent any one adverse outcome and $471,000 to prevent a death from an automobile crash or from human immunodeficiency virus infection. Assuming society were willing to pay $600,000 to prevent a death (a generally accepted figure), the program would be cost-effective only if it were 5.6% effective at changing behavior. At this efficacy, the program would have a cost per year of life saved comparable to or better than many other accepted medical interventions. However, to demonstrate changes in outcomes at this efficacy would require a clinical trial with between 4000 and 95 million adolescents in each treatment group, depending on the outcome measured.
CONCLUSIONS: Studying the ability of clinical preventive services to prevent outcomes of adolescents' risky behaviors would be impractical. The decision to implement these programs should be made based on current knowledge and beliefs; their efficacy can probably be studied only as part of widespread implementation.