Audit of Oral Anticoagulation in Atrial Fibrillation (AF)

Back Audit of Oral Anticoagulation in Atrial Fibrillation (AF)

Carmel Medical Practice December 2016
Professor Ahmet Fuat


The most common cardiac arrhythmia is AF and the incidence increases with age.1,2

1,200,000 people have AF in the UK and more than 250,000 people are thought to be living with AF undiagnosed.  Risk of stroke increases by five times in AF. 3,4

AF is estimated to be responsible for 15-20% of all strokes. Treatment with Warfarin or one of the Newer Oral Anticoagulants (NOACs) provide evidence based reductions in Stroke and are NICE approved. Aspirin is no longer recommended as mono thera-py for Stroke prevention in AF. 5

Audit criteria

  • Ensure safe prescribing of warfarin and NOACs according to license, CHA2DS2-VASc score and HASBLED score calculated on SystmOne
  • Those on Warfarin TTR aim is to have 90% with TTR>65% - review if TTR<65%, 2 INRs >5, 1 INR >8 in past 6m, 2 INRs <1.5 in past 6m as advised by NICE. Use validated Rosendal method to calculate TTR, exclude recordings taken in first 6 weeks and calculate over a 6 month period
  • Ensure correct NOAC doses in at least 90% of patients based on calculated Creatinine Clearance (not eGFR), Age, Weight, Co-medications based in individual drug license  ( Appendix 1)


Identify all patients with AF from our disease register. Review notes of all patients and record data using a data collection sheet (Appendix 2). Review all patients not meeting criteria.


272 patients with Atrial Fibrillation were identified, with a practice prevalence of 2.7%.

Of these patients treatment was Warfarin 66 (24.4%), NOACs 157 (57.9%), Aspirin 21 (8.1%), None 24 (9.2%) LWH 2 (0.7%) and Clopidogrel 2 (0.7%)

82.3% of total were anti coagulated (86.4% of those indicated anti coagulated as 4.1% not indicated due to low CHA2DS2VASc). 6.4% needed a review, 5.2% refused treatment with OAC and 2% OAC was contraindicated.

Of those 66 patients on Warfarin

>65% TTR = 63 (95.5%)

<65% TTR = 3   (4.5%)

Of those 157 patients on NOACS

U&Es/Creatinine checked in past 12m = 145 (92.4%)

Not done in last 12m = 12 (7.6%)

Weight checked in last 12m = 122 (77.7%)

Not done in last 12m = 35 (22.3%)

Correct NOAC dose = 140 (89.2%)

Incorrect dose = 10 (6.4%) with 8 too high and 2 too low

Unknown if correct = 7 (4.4%)

Of the 25 Patients on no treatment

11 patients treatment not indicated as CHA2DS2VASc = 0

14 patients with CHA2DS2VASc 1 or more, 7 patients refused treatment with OAC, 5 were under investigation for significant anaemia (1 of those also had severe dementia), 1 patient score 1 due to female gender so OAC not indicated, 1 patient needed review

Of the 23 Patients on Aspirin (1 with Dipyridamole too) and 2 on Clopidogrel

2 treatment not indicated as score 0, 1 score 1 due to female gender, 5 refused any OAC but happy to take Aspirin, 14 needed review. Both Clopidogrel patients needed review.


It was reassuring to see that we are identifying patients with AF with an above National average prevalence of 2.7%. We should continue to check pulse in all patients over 65 or with risk factors (HTN, Obesity, CHD, HF, CVA, DM)

We are anticoagulating a high proportion of our patients with 86.4%, and 7.2% either refusing treatment or contraindicated and 6.4% to be reviewed for consideration of an OAC. We are not regularly weighing patients with 22.3% having no weight and 7.6% no creatinine in past 12months.


Continue to screen opportunistically for AF

Audit every 6 months to above criteria

Ensure weight is recorded every time a patient with AF is having blood tests

Review the 6.4% of patients with CHA2DS2VASc of 1 or more who are not anti coagulated

1.Go AS, et al. JAMA. 2001;285(18):2370–5 

2. Heeringa J et al. Eur Heart J 2006;27:949-953 

3. British Heart Foundation. CVD Statistics Factsheet. Available at: Last accessed February 2017 

4. NICE Atrial fibrillation: management. Thousands of strokes in people with common heart rhythm disorder are avoidable, says NICE. Available at: Last accessed January 2017

5. Wolf PA, et al. Stroke 1991;22:983–988 

6. Atrial Fibrillation Preventing a Stroke Crisis. What is AF? Available at: Last accessed February 201

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