Background: Low-income mothers are more likely to experience depressive symptoms than their higher income counterparts, but they are less likely to receive treatment. One way to overcome common barriers to care for low-income women is to do therapy in the mother's home.
Aims of the study: The objective of this study was to compare the cost-effectiveness of in-home interpersonal therapy (IPT) to two standard therapies for depression treatment: office based cognitive behavioral therapy (CBT) and psychotropic medication.
Methods: This cost utility analysis used a Markov model with a 3-year time horizon to compare the cost-effectiveness of the alternate therapies from the public payer perspective. We followed a hypothetical cohort of 1,000 women age 19 to 35 years with depressive symptoms who had an income level at or below 200% of the federal poverty level. Costs were based on the number of women who completed the therapy. We used data from published literature on clinical trials with low-income minority women to determine the completion rates, duration, and effectiveness of each type of therapy. Additionally, costs for in-home IPT were calculated from unpublished trial data. Costs were determined using 2011 North Carolina Medicaid reimbursement rates; utility weights were taken from published literature. The endpoint was the total outpatient medical cost (therapy and outpatient medical visits). The study outcomes were depression free days (DFD), which were translated into quality of adjusted life years (QALY). We calculated the incremental cost-effectiveness ratio (ICER) of each therapy based on the number of QALYs gained. We conducted deterministic and probabilistic sensitivity analyses to determine how robust the results were to uncertainty in the parameters.
Results: Treating patients with IPT resulted in an ICER of USD 13,479/QALY and USD 29,309/QALY as compared to CBT and medications, respectively. The results were most sensitive to the efficacy of IPT. Simulations showed that, with a threshold of USD 50,000/QALY, IPT was cost-effective 95% and 78% of the time as compared to CBT and medications, respectively. If policy makers were willing to pay USD 50,000 per QALY, IPT had a 0.586 probability of being the cost-effective option relative to medication and in-office CBT.
Discussion: Due to higher completion rates, in-home IPT cost more but resulted in more QALYs gained than the other therapies. Our results indicated that in-home IPT was cost-effective as compared to office-based CBT and at least as cost-effective as medication therapy. The analysis was based on limited data because there have been few randomized, controlled studies on treatments for depression in low-income women, however; additional studies are needed to improve the accuracy of the model.
Implications for health policy: In coming years, the number of low-income women covered by public insurance should increase due to the Affordable Care Act. Given the high prevalence of depression in this population, it will be important to consider the value of potential resources spent on depression treatments. This study found that both in-home IPT and medication could be cost-effective treatments for depression. The results of this study support public payers reimbursing for in-home services.