Cost utility analysis of maintenance treatment for recurrent depression

This paper presents a cost-utility analysis of three maintenance treatments for recurrent depression: interpersonal therapy (IPT-M), imipramine drug therapy (Drug), and a combination of the two. We base our analysis on the results of the University of Pittsburgh's Controlled Clinical Trial of Maintenance Therapies for Recurrent Depression. We construct a Markovian state-transition model to incorporate clinical effectiveness into cost and quality-of-life impacts; we assign empirical values to the parameters of this model; and we then use Monte Carlo analysis to compare the relative cost effectiveness of the different maintenance treatments. For the patients who met the eligibility standards for the study, Drug maintenance treatment is cost-effective in the strongest sense of the term compared to either a placebo group or IPT-M: it both improves expected lifetime health (measured in quality-adjusted life years, or QALYs) and reduces direct medical costs. This is true even when relatively severe side effects of the drug are considered. Compared to the placebo group, IPT-M and the combination of IPT-M and Drug each improve expected lifetime health, although in neither case are expected direct medical costs reduced. Still, the cost of the resulting health improvements, under $5000/QALY, are very reasonable. A similar conclusion holds comparing Drug and IPT-M to IPT-M alone. All of the above conclusions are quite robust to sensitivity analyses.