New research from the University of British Columbia suggests that a specialized genetic test designed to determine the most effective antidepressant for patients with moderate-to-severe depression could lead to substantial cost savings for the health system and significantly improve patient outcomes.
The study, published in the Canadian Medical Association Journal (CMAJ), indicates that implementing pharmacogenomic testing in British Columbia alone could save the provincial public health system an estimated $956 million over a 20-year period. Pharmacogenomic testing aims to match patients with antidepressant medications that are more likely to be effective and cause fewer side effects based on their genetic profile.
Dr. Stirling Bryan, co-senior author and professor at UBC’s school of population and public health, emphasized that this testing could provide enormous benefits to patients, including increased remission rates and a better quality of life. Additionally, it could generate significant cost savings by keeping people out of hospitals and preventing the need for more intensive treatment pathways.Â
Major depression affects one in 10 Canadians at some point in their lives, making it a significant public health burden. Although over 35 antidepressant medications are available in Canada, more than half of patients do not respond to their initially prescribed antidepressant and approximately 27% report adverse effects.
Genetic factors account for up to 42% of the variation in how patients respond to these medications. Pharmacogenomic testing involves using genetic information, often obtained through a cheek swab, blood test, or saliva sample, to guide medication selection and dosing.
Dr. Jehannine Austin, co-senior author and professor of medical genetics and psychiatry at UBC, explained that genes play a crucial role in how the body metabolizes different antidepressants, influencing their efficacy. The insights provided by pharmacogenomic testing can help physicians make more informed treatment decisions, reducing the trial-and-error process many patients undergo in finding an effective medication.Â
To assess the potential impact of pharmacogenomic testing, the researchers developed a simulation model in collaboration with patient partners, clinicians, and health system and government partners. The model, incorporating B.C. health administrative data, clinical trial data, and defined treatment strategies, compared the projected journey of 194,149 adults with and without pharmacogenomic testing over a 20-year period.Â
The simulation model revealed that pharmacogenomic testing could result in 37% fewer patients experiencing treatment-resistant depression, a situation where depression does not improve despite trying multiple treatments. Patients undergoing pharmacogenomic testing would also spend 15% more time without depression symptoms, leading to an anticipated 1,869 fewer deaths and 21,346 fewer hospital admissions over 20 years.Â
Dr. Shahzad Ghanbarian, the first author and a mathematical modeler and health economist, explained that by incorporating patient perspectives and robust data sets, they were able to simulate the treatment journey of people with major depression. The researchers believe the flexible simulation model could be applied to other jurisdictions beyond B.C. to anticipate similar benefits within a comparable Canadian context.Â
Linda Riches, a resident of Salmon Valley, B.C., who has lived with major depression for over 30 years and participated as a patient partner in the study, highlighted the importance of genetic testing. She stated that people with major depression deserve to feel hopeful about their lives, and genetic testing may provide them with the opportunity to know the most suitable treatment for their condition.Â
While pharmacogenomic tests are not currently offered through public health systems across Canada, patients can opt for them through private companies. The researchers argue that their analysis strongly supports the inclusion of pharmacogenomic testing as part of routine, publicly funded healthcare for people with major depression in B.C. However, further work is needed to determine the practical implementation of such testing, with input from patients, physicians, government, and health sector partners.Â
Journal Reference Â
Cost-effectiveness of pharmacogenomic-guided treatment for major depression, Canadian Medical Association Journal (2023). DOI: 10.1503/cmaj.221785Â
