15.1 Audit of anticoagulation

15.1.1 AUDIT OF ANTICOAGULATION IN INPATIENT CARE

Key points for audit of heparin treatment in hospital are noted at Annex 1.¹⁸³ Key points for audit of warfarin initiation are noted at Annex 2.¹⁸³ Because many patients start warfarin during the initial exposure to heparin, many of the Practice and Audit Points are the same.

The objective is to examine anticoagulation in patients in whom heparin or warfarin is introduced in hospital, before and after the introduction of the local guideline for anticoagulation. The method is a retrospective review of the case notes of a sample of recent patients treated with heparin or warfarin in the wards, utilising the identification of essential practice points and audit of their documentation.¹⁸⁴

The initial audit provides an indication of baseline local standards for initiation of anticoagulation. An identical audit carried out several months after the introduction of the local guideline for anticoagulation allows an assessment of changes in standards. This exercise should also enable identification of reasons for any failure to meet the guideline standards and methods to improve awareness of the guideline.

Potential factors which may reduce impact of the guideline include:

• inaccessibility
• methods of reporting and filing of results
• failure of computer networks
• methods of documentation

Potential methods to improve awareness of the guideline include:

• display on ward notice boards
• reminder each time APTT ratio or INR ordered (laboratory)
• reminder each time heparin or warfarin prescribed (pharmacy)
• incorporation in ward information booklets
• dissemination to all junior doctors
• presentation in brief note form
• incorporation into hospital computer system.

A further audit after consideration of such factors completes the final audit loop.

15.1.2 AUDIT OF ANTICOAGULATION IN GENERAL PRACTICE OR HOSPITAL OUTPATIENT CLINIC

Key points for audit are noted at Annex 3. The objective is to examine oral anticoagulant management in patients attending either their general practitioner or a hospital outpatient clinic. The method is a retrospective analysis of a sample of case records of current attenders at the clinic utilising the identification of essential practice points and audit of their documentation.¹⁸⁴

The initial audit provides an indication of current local standards for long term oral anticoagulation e.g. the recording of essential information; the appropriateness of therapeutic ranges for individual patients; the documentation of critical events and the identification of their causes; and the percentage of patients within their appropriate INR therapeutic range. An identical audit several months after the introduction of a local guideline allows an assessment of changes in standards. This exercise should also enable identification of reasons for any failure to meet the standards in the local guideline.

15.2 Recommendations for research

• Management studies of risk stratification in clinically-suspected DVT or PE using combinations of clinical variables and non-invasive laboratory variables (e.g. fibrin D-dimer).
• Management studies of out-patient treatment of DVT.
• Studies of optimal duration of warfarin in patients with DVT or PE.
• Management studies of risk stratification and selective oral anticoagulant prophylaxis in atrial fibrillation using combinations of clinical variables and laboratory variables (e.g. echocardiography, fibrin D-dimer).
• Management studies of risk stratification and selective oral anticoagulant prophylaxis in patients with arterial disease using combinations of clinical variables and laboratory variables (e.g. fibrinogen, fibrin D-dimer).
• Management studies of risk stratification and selective antiplatelet or oral anticoagulant prophylaxis in patients at increased risk of arterial thrombosis using combinations of clinical variables and laboratory variables (e.g. ankle-brachial pressure index, fibrinogen, fibrin D-dimer).
• Management studies of control of oral anticoagulant therapy in primary and secondary care, e.g. pharmacist, nurse specialist, patient and computer-led management.
• Studies of new anticoagulant drugs requiring less monitoring than warfarin.