Warfarin Patient Safety Audit: patient data-analysis tool for GP practices
a significantly reduced risk of stroke. Only those with control in excess of over 40% have significantly improved outcomes in terms of overall mortality compared to treatment without warfarin. Results in the summary sheet have recently been altered to now highlight percentage time in TTR using a 65% value, rather than 70%. This change was made to reflect the NICE recommendation that any patient with a TTR below 65% should have anticoagulation reassessed.
Warfarin Patient Safety is an audit tool produced by PRIMIS that is freely available for GP practices in England. Here, the authors explain what is does and how it works. The Warfarin Patient Safety audit tool enables practices to audit their clinical data to look at the appropriateness of warfarin prescribing. In particular, the tool assists in examining whether patients are benefitting from taking warfarin by calculating the amount of time their INR is within therapeutic range (TTR). PRIMIS’ development of the audit tool has been funded by Boehringer Ingelheim Ltd. What does the audit do? The audit tool is concerned with patients who are established on warfarin. It is based on patients who are currently registered at the practice who have had an issue of warfarin both recently (in the last three months) and historically (in the preceding nine months). This produces a cohort that is more relevant for the analyses. The audit tool: n calculates the percentage of time spent in therapeutic range (TTR) from the INRs recorded in the patient’s electronic record n identifies patients with out of range INRs as recommended in the BCSH Guidelines on Oral Anticoagulation1
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n calculates the HAS-BLED2 risk score (patients with atrial fibrillation only) and compares it with the patient’s CHA2DS2VASc3 score n reports on patients with or without an identified coded reason for being on warfarin and patients with or without a coded annual warfarin assessment n identifies patients who have had too few or too many INRs over the past 12 months and may therefore be poorly managed How does the audit work? The audit tool works in conjunction with CHART, a software tool also produced by PRIMIS. CHART (Care and Health Analysis in Real Time) is a Microsoft Excel-based program, designed to support GP practices in carrying out clinical audit and data quality reviews. GP practices use the various displays within CHART to review clinical data at both patient and practice level, enabling them to maintain an overall picture of how they are managing patients at a population level but, at the same time, be able to look in detail at the care of individual patients. The Warfarin Patient Safety audit tool produces a practice
Figure 1a: Practice report for the Warfarin Patient Safety audit tool showing that 10 patients have a TTR of less than 40%. A further 55 patients have a TTR between 40-65%.
report summarising the outcome, together with some suggested actions. The results are displayed in a user-friendly format, with easyto-read graphs, tables and an evidence-based narrative.
Figure 1b: The datasheet for the Warfarin Patient Safety audit tool enables practices to easily access and sort the TTRs for each patient included in the audit
Warfarin Patient Safety Audit examples
Out of ranges INR results
Time in Therapeutic Range (TTR)
A patient’s risk of bleeding increases with their INR. The categories reported on in the audit tool are based on specific recommended safety indicators for patients established on anticoagulation. These patients need to be reviewed to see if there is anything which can be done to improve their control:
It is critical that patients prescribed warfarin achieve their desired INR for anticoagulation to be effective. The audit tool uses the Rosendaal4 method to calculate the percentage of time a patient spends within the therapeutic range (TTR). Evidence from a study on patients with AF5 indicates that only patients with a TTR greater than 70% have
n INR above 5 - the risk of bleeding is significantly increased Figure 1a
Percentage time in therapeutic range (TTR) TTR under 40%
TTR 40% - 65%
TTR over 65%
Number of patients
10
55
96
% of all patients with a TTR
6.2
34.2
59.6 Figure 1b
Reference
Age
Sex
Percentage TTR L6M
Percentage TTR L3M
FFBCD3172
85
M
18.9
18.19
BEEDD350
76
F
23.77
23.77
8387F688D
79
F
24.37
24.37
n INR above 8 – can be dangerous and requires urgent reversal n INR more than 1 unit below the target – patients are generally not adequately anti-coagulated Figure 2: The practice report for the Warfarin Patient Safety audit tool shows both the number of INRs and the number of patients involved (the number of patients appears in brackets), categorised according to safety indicators HAS-BLED score HAS-BLED is a bleeding risk assessment tool used for patients with atrial fibrillation. The new draft guidance6 on the management of atrial fibrillation from NICE recommends that GPs should use the HAS-BLED score to assess the risk of bleeding both when initiating anticoagulation therapy and
monitoring patients. A HASBLED score of 3 or more is generally considered high risk but this alone should not stop the use of anticoagulation therapy. HAS-BLED can be used with the CHADS2 or CHA2DS2-VASc scores to help clinicians balance the risk of bleeding with the risk of stroke, determining whether anticoagulation is in the best interest of the patient.
reporting and display functionality that allows benchmarking and comparison both locally and nationally of pseudonymised results. This new feature will enable practices to upload their audit tool results
PRIMIS’s development of the Warfarin Patient Safety audit tool has been funded by Boehringer Ingelheim Ltd. PRIMIS retains editorial control and intellectual property rights for the audit tool.
Figure 4: example of pseudonymised results in CHART Online
Dr Robinson is a GP and Clinical Adviser and Kerry Oliver is Managing Director at PRIMIS, The University of Nottingham, www.nottingham.ac.uk/primis
Figure 3: Warfarin Patient Safety audit tool, showing there are 25 patients with a HAS-BLED score of 3 or more on warfarin and 11 patients with a low risk CHA2DS2-VASc score on warfarin
PRIMIS is a business unit in the Division of Primary Care at The University of Nottingham. PRIMIS provides education and informatics services to GP practices, the NHS, commercial organisations and researchers.
PRIMIS
Recent improvements Warfarin Patient Safety has been upgraded in 2015 to enable CHART Online functionality. CHART Online is a data storage facility at PRIMIS with associated Figure 2 INR>8
INR>5
INR>1 unit below target
Number of INRs (patients)
1 (1)
6 (6)
25 (16)
% of all INRs
0.1%
0.7%
2.9%
Both CHART and the Warfarin Patient Audit Tool are free to use by all GP practices in England and can be downloaded by members of the PRIMIS Hub. Hub members have access to information, advice, training and tools aimed at supporting effective use of health information, helping to achieve better health outcomes and basic Hub membership is free. Figure 3
HAS-BLED Risk score v CHA2DS2-VASc Risk score
n HAS-BLED risc score 0
n HAS-BLED risc score 1 n HAS-BLED risc score 2 n HAS-BLED risc score 3 or more 2
CHA2DS2VASc low risk (=0)
5
1
CHA2DS2VASc med risk (=1)
0
4
19
11
4 References
CHA2DS2VASc high risk (>1) 0 0%
25 20%
27 40%
21 60%
80%
100%
Percentage of patients
Figure 4
1. Baglin T. P., Cousins D., Keeling D. M., Perry D. J. and Watson H. G. (2006) Recommendations from the British Committee for Standards in Haematology and National Patient Safety Agency, British Journal of Haematology, 136, 26–29 2. Pisters R., Lane D. A., Nieuwlaat R., de Vos C. B., Crijns H. J. G. M. and Lip G. Y. H. (2010) A Novel User-Friendly Score (HAS-BLED) To Assess 1-Year Risk of Major Bleeding in Patients With Atrial Fibrillation Chest, 138, 1093-1100 3. Use of the CHADS2 risk score is recommended in the European Society of Cardiology (ESC) (2010) Guidelines for the management of atrial fibrillation: the Task Force for the Management of Atrial Fibrillation of the ESC. European Heart Journal; 31(19): 2369-429. 4. Rosendaal F. R., S. C. Cannegieter, van der Meer F. J. M., and Briet E. (1993) A Method to Determine the Optimal Intensity of Oral Anticoagulant Therapy, Thrombosis and Haemostasis; 69(3): 236-239 5. Morgan C. L., McEwan P., Tukiendorf A., Robinson P. A., Clemens A., Plumb J. M., (2009) Warfarin treatment in patients with atrial fibrillation: Observing outcomes associated with varying levels of INR control, Thrombosis Research; 124: 37-41 6. National Clinical Guideline Centre (2014) Atrial fibrillation: the management of atrial fibrillation (draft for consultation), Clinical Guideline, http://guidance.nice.org.uk/CG/Wave0/638/ Development/Consultation/DraftGuidance/pdf/ English
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