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How I assess what patients know about warfarin

Dr Rohit Sethi explains how he used a short online questionnaire to assess the knowledge of his warfarin patients about their treatment – with shocking results.

Dr Rohit Sethi explains how he used a short online questionnaire to assess the knowledge of his warfarin patients about their treatment – with shocking results.

Primary care is managing more and more patients on oral anticoagulation therapy, but warfarin therapy requires a great deal of care and expertise in its administration.

Patients who have a greater understanding of their condition and therapy are able to participate more in self-care with better outcomes. Following a warfarin-related adverse event in our own practice (directly related to deficient patient knowledge) we decided to carefully monitor what our patients know about their treatment.

We developed an audit and education tool which assesses patient knowledge about their warfarin treatment, and then fills their knowledge gaps.

What we did

A letter of invitation was sent to 81 patients. They were invited to use the health tool online (via the practice web site) or via a paper-based questionnaire.

Patients were encouraged to use the online version as this saved on practice staff time entering data at a later stage. Patients were also able to immediately view the answers to the questions that they got wrong – an important step in improving their knowledge about their treatment.

Patients using the paper based version were sent the answers to incorrect questions at a later date.


We asked the following 17 questions in the questionnaire:

  • Do you know what Warfarin is?
  • Do you know how Warfarin works?
  • Do you know why you are on Warfarin?
  • Do you know what the test is for measuring the effect of warfarin?
  • Do you know what INR stands for and what the test results mean?
  • Do you know what your target INR is?
  • Do you know how long you should be on treatment for?
  • Do you know how often your INR test is done?
  • Do you have a special book to record your test results?
  • Do you have an anti-coagulation alert card?
  • Are you clear about how you obtain your INR blood test results?
  • Do you know what the risks are for patients taking warfarin?
  • Do you know what to do if you bleed whilst taking warfarin?
  • Do you know which foods can affect warfarin?
  • Do you know which other drugs can affect warfarin?
  • Do you know how alcohol can affect warfarin?
  • Do you know who to contact if you are concerned about bleeding or your INR result?

The response

Responses were obtained from 61 out of 83 patients. About half of the respondents used the online tool. The range of incorrect answers was 17 to 0 with a mean of 5.

The 5 most common incorrect answers were to the following questions:

Do you know which other drugs can affect Warfarin? (44 incorrect)

Do you have an anti-coagulation alert card? (44)

Do you know which foods can affect Warfarin? (38)

Do you know what to do if you bleed whilst taking Warfarin? (26)

Do you know how alcohol can affect Warfarin? (25)

Follow-up

Follow-up with patients who used this tool found it educationally useful and thought that it helped them understand and manage their warfarin management better.

The three out of six partners who used this tool as part of the annual review process found that it saved on time and provided a much more thorough review than a face-to-face consultation might have provided.

With the potential increase in numbers of patient on warfarin and also the future role of self-monitoring a health tool that helps patients to increase their knowledge and enable self-care can only be of positive benefit.

The health tool is now available to PCT's, locality groups, commissioners and hospital trusts.

Dr Rohit Sethi is a GP in Cirencester, Gloucestershire

How I assess what patients know about warfarin Questionnaire 1 Questionnaire 2 Questionaire 3

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