Cost-Effectiveness of a Pharmacogenetic Test to Guide Treatment for Major Depressive Disorder

Vu Ha, Pharm.D., Community University Health Care Center

Background: Major depressive disorder (MDD) is a complex, yet commonly diagnosed medical condition. Signs and symptoms can range from decreased energy to difficulty concentrating and persistent feelings of hopelessness that directly impacts patients’ daily living activities. Suicide rates are higher for patients with treatment-resistant depression (0.16%) than patients who responded to therapy (0.09%). There are numerous pharmacotherapeutic options available to treat MDD which are selected based on specific patient factors, costs, and provider comfortability. More recently, pharmacogenomics have been utilized to further individualize MDD therapy by identifying possible genetic profile-drug interactions, thus increasing the response rate.

Objective: The authors investigated the use of IDgenetix (IDGx) pharmacogenetic testing prior to initiating​ pharmacotherapy and compared this approach to medication management, the current standard of care (SOC), to determine which process was more cost-effective and had higher rates of successful treatments.

Study Design: Authors collected data from a large prospective, multicenter, randomized control trial of patients with inadequately controlled MDD who received either IDGx or SOC. The study evaluated the effects of poorly treated and untreated disease burden on quality-adjusted life-years (QALYs), total costs (direct and non-direct), and suicide rates over a three-year period. Researchers utilized the 17-item Hamilton Rating Scale for Depression to determine the severity of depression. Utility scores were also obtained from a previous study through a standardized tool used to measure generic health outcomes and examine cost-effectiveness with new treatments among responders and non-responders. Univariate, one-way sensitivity analyses were performed based on 95% confidence intervals for response rates, suicide rates, and utility scores.

Results: Results were favorable for patients with moderate to severe MDD who had received IDGx prior to clinician initiating pharmacotherapy in terms of QALYs, costs to patients, and response rates. After a period of three years, the model estimated a score of 2.07 QALYs for IGDx group compared to that of 1.97 QALYs for SOC group. The probability of death from suicide was also lower with the IDGx group [0.328%] than the SOC group [0.351%]. Overall cost in the three-year period ($44,697) was lower for IDGx group than SOC group even factoring in the initial cost of $2,000 for the pharmacogenetic testing to be performed.

Conclusions: Based on QALYs and death from suicide rates, it is estimated that 4,300 patients would need to be tested to prevent one death from suicide. This is significant as 6.7% of the United States population is affected by MDD. It is estimated that IDGx application can prevent 5,000 deaths from suicide which would approximately be a 12% reduction. The initial cost of $2,000 for IDGx may deter some patients and clinicians from initiating the tests. However, these costs can be recovered within two years. The use of pharmacogenetic testing can further help clinicians successfully select the appropriate antidepressant therapy to minimize side effects while maximizing response rates and reducing costs.

Key Point: When treating patients with moderate to severe major depressive disorder, pharmacogenetic testing can help improve the quality of life and minimize healthcare costs. Pharmacists should be aware of the implications with this expanding tool and expect its use to be more widespread in the coming years.

Reference:

1. Groessl, EJ, Tally, SR, Hillery, N, Maciel A, & Garces JA. Cost-effectiveness of a pharmacogenetic test to guide treatment for major depressive disorder. J. Manag. Care Spec. Pharm. Aug 2018. 24(2): pg 726-734.