NB KISS: DOACs - Don’t Omit to Assess Creatinine clearance

One of the key things we try to do at NB is make your life that little bit easier. Working in primary care can be hugely rewarding, but it can also be busy, complicated and stressful. The KISS summaries we produce are aimed at being a succinct summary of a clinical topic that, importantly, we hope can be used at the coal face in the middle of a busy surgery or whilst reviewing the never ending list of prescriptions and path results. 

Ploughing through said list of prescriptions on Monday it hit me, as we are discussing in our latest Hot Topics course, the huge number of people with AF who are therefore (usually) on a DOAC. The latest data suggests that we have a 1:3 chance of developing AF in our lifetime, so the numbers of people on DOACs is only set to increase.

The advent of DOACs for treating AF has led to a big and positive change for our patients. Anticoagulation rates are improving and stroke rates are falling. But whilst the evidence generally shows DOACs are safer than warfarin, it is easy to forget that DOACs are not necessarily ‘safe’ drugs - they can still cause clinically significant bleeding and DO need monitoring, with evidence confirming that incorrect dosing based on renal function leads to higher complication rates. It’s worth a reminder that dosing needs to be done on the creatinine clearance/CrCl (embedded now in most clinical systems) NOT eGFR. 

And we’ve still got work to do on this - a recent observational study based on English General Practice data and reported in the DTB last year  showed that as of ~2020 40-50% of people on DOACs for AF were being prescribed incorrect doses based on CrCl. Regarding monitoring, as a simple ‘rule of thumb’ the AHA suggests that once CrCl has fallen <60 the frequency of renal function monitoring (in months) can be guided by dividing the CrCl by 10 i.e. CrCl of 40 = 40/10 = 4 so do U&E every 4 months. 

So how can I help you with this as you plough through your path results and prescriptions? A handy 1 page table with all the DOACs with dosing guided by indication, CrCl and other factors such as age and weight, so you can quickly cross reference the the DOAC dose and when they need their next U&E? Your wish is my command! An NB KISS on all things DOACs and dosing easily accessible at your fingertips!