Genotype-guided warfarin dosing reduced a combination of adverse events, compared to clinically guided dosing among older patients treated with warfarin before elective hip or knee arthroplasty, according to a study published Sept. 26 in the Journal of the American Medical Association (JAMA). While single clinical outcomes, like major bleeding events, were not statistically improved with genotype-guided dosing, the study provides evidence of the overall reduction in adverse events from a genotype-guided dosing regimen at initiation of warfarin that may inform future coverage decisions, the authors say. Previous studies show that warfarin accounts for more medication- related emergency department visits among older patients than any other drug. While the product label for warfarin encourages genotype-guided dosing, evidence has been mixed as to whether or not genotype-guided dosing meaningfully improves the safety of warfarin initiation. In addition to concerns about clinical utility, adoption of clinical pharmacogenomic testing has been hampered by lack of payer coverage and logistical constraints in returning results fast enough to impact decision making in non-elective situations. "Compared with previous studies, this trial was larger, used genotype-guided dosing for a longer duration, and incorporated more genes into the dosing algorithm." —Brian F. Gage, M.D. The present study, the Genetic […]