Abstract 95 Poster Session III, Monday, 5/3 (poster 363)

Background. Attention deficit hyperactivity disorder (ADHD) affects 3 - 5% of school-age children and is associated with significant educational and social impact and high rates of pharmaceutical prescription. In choosing between the available treatment modalities, it is critical to establish not only their clinical efficacy, but also their value for money, in comparison to other uses of the same resources.

Objective. To establish the cost-effectiveness of five alternative modes of therapy for ADHD, including methylphenidate (MPH), pemoline and dextroamphetamine, as well as psychological/behavioral treatment and a combination MPH-behavioral strategy.

Design. Incremental cost-effectiveness analysis with decision analytic modeling.

Methods. The analysis was structured using a decision analytic tree that incorporated typical clinical algorithms from published guidelines. A third-party payer perspective was maintained and results modeled over a 1-year time horizon, using no treatment as the baseline comparator. Effectiveness data were derived from a meta-analysis previously reported by members of our group (Pediatric Research 1998;43(4):A60). Effectiveness outcomes were reported as reduction in scores on the Abbreviated Connor's Teacher Rating Scale (CTRS), as this behavioral measure is well accepted and common to the studies examined. Costs reflected market prices as the best estimate of true alternative uses for resources. Unit drug prices were national averages and included mark-ups and dispensing fees. Costs for professional services were obtained from provincial and professional association fee schedules and a survey of expert clinicians. All expenditures were expressed in 1997 Canadian dollars. Because pemoline has been linked to potentially fatal toxic hepatitis, the analysis was repeated after excluding it from consideration.

Results. MPH cost $83 (CAN) for each point reduction in the CTRS over one year, or $498 (CAN) for a clinically significant improvement in behavior (6 points on the CTRS). With pemoline excluded from consideration, MPH therapy cost less and was more effective than any other options examined (strict dominance). When pemoline was included, it was a more expensive option, costing an additional $1476 (CAN) for each additional one-year clinically significant improvement, beyond that achieved by MPH. The results were robust to extensive sensitivity analyses, in which input variables were varied through a range of plausible values.

Conclusion. Methylphenidate therapy for ADHD has a cost-effectiveness well within the range considered acceptable for other pediatric medical interventions, and is preferred over all other available options. Given the small size and methodological limitations of the trials underlying the efficacy estimates for psychological/behavioral therapies, these results should be re-examined as better quality clinical trial data for non-medical therapies are incorporated into future meta-analyses.

Dr. Zupancic is supported in part by a Clinician Scientist Award from the Medical Research Council of Canada. This study was funded by a grant to Dr. Miller from the Canadian Coordinating Office for Health Technology Assessment.