DOAC contraindications

[brianmackenna]

Contraindications where DOACs have been explicitly contraindicated

[brianmackenna]

Draft

https://codelists.opensafely.org/builder/brian-mackenna/explicit-contraindication-to-doacs-direct-acting-anticoagulants

[brianmackenna]

@richiecroker the following has been created with codelist builder to identify where there is an explicit contraindication that is specific to DOACs. Interestingly edoxaban doesn't seem complete as the rest of them.

One query I'm not sure what ancrod is but it is in hierarchy directly below DOAC so I included in case it comes up in picking lists and is selected. No strong feeling if we exclude - i bet prevalence is low.

id	term
Xa5Zo	Direct acting anticoagulant adverse reaction
Xa5Zp	Ancrod adverse reaction
Xa5yH	Direct acting anticoagulant allergy
Xa5yI	Ancrod allergy
XaZbj	Dabigatran contraindicated
XaZbr	Dabigatran not tolerated
XabEn	Novel oral anticoagulant contraindicated
XabEo	Novel oral anticoagulant not tolerated
Xad9m	Apixaban adverse reaction
Xad9n	Rivaroxaban adverse reaction
Xad9o	Rivaroxaban allergy
Xad9p	Apixaban allergy
Xad9s	Apixaban not tolerated
Xad9t	Rivaroxaban not tolerated
XadAI	Apixaban contraindicated
XadAK	Rivaroxaban contraindicated

There are a few small bugs in the reconciling page that means I haven't been able to confirm exclusion of some codes on the interface but I think this codelists is complete.

[richiecroker]

@brianmackenna

Ancrod, marketed as Viprinex, is a defibrinogenating agent derived from Malayan pit viper venom. The defribrinogenation of blood results in an anticoagulant effect. Currently, Viprinex®/ancrod is not approved or marketed in any country, but is being investigated as a stroke treatment in worldwide clinical trials. In January 2005, the U.S. FDA granted a 'fast-track status' for investigation of ancrod use in patients suffering from acute ischemic stroke, a life threatening condition caused by the blockage of blood vessels supplying blood and oxygen to portions of the brain, for which phase III trials are currently being conducted.

I'd be surprised if there's anyone on it in the UK. It doesn't look like a DOAC however - so it could come out. I'm not sure it matters either way!

[richiecroker]

As you say, also interesting that there is not consistency on approach for flagging lack of tolerability - 4 for rivar and apixaban, 2 for dabigatran and none for edoxaban. I assume the edoxaban would be covered by the NOAC ones?

[brianmackenna]

Well depends what a clinician enters e.g. they would also be covered by anticoagulation contraindicated NOS. Yep interesting with edoxaban and inconsistency. I'll remove ancrod.

Happy otherwise with list?

[richiecroker]

anticoagulation contraindicated NOS not in list?

[richiecroker]

But yes, happy with list (apart from anticoagulation contraindicated NOS query)

[brianmackenna]

Because we are explicitly looking for DOACs contraindicated for this study.

anticoagulation contraindicated NOS obviously encompasses more. There's actually loads of similar unspecific codes. Will include these nuances in description

[richiecroker]

fair enough. List looks fine.

[brianmackenna]

https://codelists.opensafely.org/codelist/opensafely/explicit-contraindication-to-doacs-direct-acting-anticoagulants/2020-10-19/

I have documented edoxaban inconsistency here https://github.com/opensafely/opencodelists/issues/278