Impact of Weighted Multi-Gene Pharmacogenomic Testing on Hospitalization Rates in a Real-World Dataset of Patients with Major Depressive Disorder

Purpose: To investigate real-world outcomes pre- and post- pharmacogenomic (PGx) testing, this study determined 1) the proportion of patients with major depressive disorder (MDD) taking medications with significant gene-drug interactions (GDI) and 2) hospitalizations in a large US claims dataset.
Methods: Adult patients with MDD who received PGx testing between 01/01/2015 and 09/30/2021 were linked with de-identified US claims data. The PGx report organized psychiatric medications as: no known GDI (congruent), moderate GDI (congruent), and significant GDI (incongruent). Patients were considered as taking incongruent medications if any of their prescribed medications were incongruent. Patients were assigned to the following groups based on their medication congruency at 90 days pre- and post-PGx testing: no change, incongruent-to-congruent, and congruent-to-incongruent. Hospitalizations were compared in the 180 days pre- and post-PGx testing.
Results: A total of 20,933 patients met inclusion criteria. In the 16,965 patients prescribed medications 90 days pre- and post-PGx testing, significant GDIs were reduced post- compared to pre-PGx testing (16% vs. 26%). Significant reductions were observed pre- to post-PGx testing in the proportion of patients with hospitalizations for any reason (29% relative decrease, p < 0.001). Psychiatric hospitalizations were also significantly reduced (39% relative decrease, p < 0.001), specifically in the incongruent-to-congruent (44% relative reduction, p < 0.001) and no change in congruency (39% relative reduction, p < 0.001) categories. The proportion of patients with non-psychiatric hospitalizations did not significantly change.
Conclusions: Post-PGx testing, fewer patients were prescribed medications with significant GDI, and healthcare resource utilization was reduced, potentially driven by those in the incongruent-to-congruent and no change groups.