Effect of future costs on cost-effectiveness of medical interventions among young adults: The example of intensive therapy for type 1 diabetes mellitus

Objectives. Recent research based on a life-time utility maximization model has suggested that cost-effectiveness analyses should account for all future costs, including medical costs for related and unrelated illnesses and nonmedical costs. This work has also shown that analyses that omit future costs are biased to favor interventions among the elderly that extend life over interventions that improve quality of life. However, the effect of including future costs on the cost-effectiveness of interventions among the young has not been studied. This article examines the effect of including future costs on the cost-effectiveness of intensive therapy for type 1 diabetes mellitus among young adults. Methods. By modifying a cost-effectiveness model based on the Diabetes Control and Complications Trial to include future costs, the effect of including future costs on the cost-effectiveness of intensive therapy for type 1 diabetes mellitus among young adults was examined. Future costs added to the model included future costs for medical expenditures for illnesses unrelated to diabetes and future nonmedical expenditures net of earnings. Results. Intensive therapy among young adults led to approximately equal increases in the expected number of years lived before age 65, when people generally produce more than they consume, and after age 65, when the opposite tends to hold. Because the discounted value of savings due to lower mortality before age 65 exceeded the discounted value of later increases in costs due to lower mortality after age 65, accounting for future costs decreased the cost-effectiveness ratio from $22,576 to $9,626 per quality-adjusted life-year. Conclusions. The inclusion of future costs can significantly improve the cost-effectiveness of interventions that decrease mortality among young adults. The common practice of excluding future costs may bias cost-effectiveness analyses against such interventions.