Hot off the presses atthe American Heart Association conference, results of a geneotypic based coumadin dosing strategy were released. The results of this 200 person study were pretty neat. from MedPageToday
"Out-of-therapeutic-range prothrombin times were not less common with the pharmacogenetic algorithm than with standard empirical dosing, But initial doses chosen based on genotype were closer to patients' eventual stable doses (P
<0.001) and subsequent dosing adjustments were smaller (P=0.002) and less frequent (P=0.03) than with empirical dosing, reported Jeffrey L. Anderson, M.D., of Intermountain Healthcare and the University of Utah in Salt Lake City, and colleagues."
"The Couma-Gen study included 200 adults with an indication for warfarin who were randomized to receive the drug according to a standard algorithm of 10 mg on days one and two followed by 5 mg daily or by a pharmacogenetic algorithm based on genotype, age, sex, and weight."
Most notably a subgroup analysis (which is suspect based on the small sample size) found
"Pharmacogenetic-guided dosing failed to reduce the percentage of INRs per patient that were outside the therapeutic range compared with standard dosing (30.7% versus 33.1%, P=0.47), which was the primary endpoint. However, there was a significant benefit when excluding patients with only one variant (41% of patients overall)."
So where does all of this dosing decision go from here? I await the CROWN study results as well as what Washington U St.Louis has to say.
Lastly, I have had only one comment on my last post. Why do you think DTC testing is Illegal in NY and CT. Please read this post and make a comment! The last one was pretty interesting. I wonder if he's tried do it yourself surgery yet ;)