Multisite evaluation of institutional processes and implementation determinants for pharmacogenetic testing to guide antidepressant therapy

Abstract

There is growing interest in utilizing pharmacogenetic (PGx) testing to guide antidepressant use, but there is lack of clarity on how to implement testing into clinical practice. We administered two surveys at 17 sites that had implemented or were in the process of implementing PGx testing for antidepressants. Survey 1 collected data on the process and logistics of testing. Survey 2 asked sites to rank the importance of Consolidated Framework for Implementation Research (CFIR) constructs using best-worst scaling choice experiments. Of the 17 sites, 13 had implemented testing and four were in the planning stage. Thirteen offered testing in the outpatient setting, and nine in both outpatient/inpatient settings. PGx tests were mainly ordered by psychiatry (92%) and primary care (69%) providers. CYP2C19 and CYP2D6 were the most commonly tested genes. The justification for antidepressants selected for PGx guidance was based on Clinical Pharmacogenetics Implementation Consortium guidelines (94%) and US Food and Drug Administration (FDA; 75.6%) guidance. Both institutional (53%) and commercial laboratories (53%) were used for testing. Sites varied on the methods for returning results to providers and patients. Sites were consistent in ranking CFIR constructs and identified patient needs/resources, leadership engagement, intervention knowledge/beliefs, evidence strength and quality, and the identification of champions as most important for implementation. Sites deployed similar implementation strategies and measured similar outcomes. The process of implementing PGx testing to guide antidepressant therapy varied across sites, but key drivers for successful implementation were similar and may help guide other institutions interested in providing PGx-guided pharmacotherapy for antidepressant management.

FIGURE 1

Personnel involved in antidepressant pharmacogenetic testing

FIGURE 2

Pharmacogenetic testing and return of results workflow. The most common methods for PGx testing and return of results from 17 sites implementing or planning to implement PGx testing for tailoring antidepressant therapy are provided. EHR, electronic health record; PDF, portable document format; PGx, pharmacogenetic. ^aThe most common methods are displayed in the figure; additional options can be found in Table S2

FIGURE 3

Antidepressants considered for pharmacogenetic guidance. More than one response was allowed. Only 16 of 17 sites responded. Providers may have access to the PGx report and use it to tailor additional psychotropic medications. CPIC, Clinical Pharmacogenetics Implementation Consortium; PGx, pharmacogenetic, TCA, tricyclic antidepressants

FIGURE 4

The top three constructs within each domain from the Consolidated Framework for Implementation Research (CFIR) rated as most important for implementation of pharmacogenetic testing to guide antidepressant treatment with importance scores and 95% confidence intervals