We have audited the acceptability and efficacy of self-monitoring of OAT, when offered at the start of initial anticoagulant treatment. Other than to exclude patients for whom self-monitoring was inappropriate, recruitment was non-selective; 26% of all patients (44% of eligible patients) agreed to self-monitor. Most published studies used the number of eligible patients as the denominator, making it difficult to accurately assess total uptake, but we believe that our uptake of 26% represents an improvement on previous UK studies.1
As with previous studies, a significant number of patients dropped out during or shortly after training (14%), but most of the patients who started self-monitoring completed their course of treatment or continued to self-monitor after the end of the audit period (94%). A recent systemic review1
reported that only 14% of eligible patients in the UK would conduct long-term monitoring of OAT, whereas 36% of eligible patients referred to our anticoagulation clinic were able and willing to self-monitor when offered self-monitoring at the start of anticoagulation. As with previous studies, self-monitoring patients were younger than the clinic population as a whole,1
but we found no gender-related difference in uptake.
The %TIR for self-monitoring patients in this audit is similar to that observed in previous studies in the UK2–7
and a recent study performed in the Netherlands,15
and superior to that in a large Spanish study.16
Most other studies of self-monitoring of OAT were performed in countries where specialised hospital anticoagulant clinics are not normal clinical practice. Consequently, it is not appropriate to discuss these studies here.
While the uptake and retention of patients in our audit were superior to those in previous studies performed in the UK and the Netherlands (where anticoagulation is usually undertaken in specialist hospital-based clinics), recruitment was higher in the Spanish study16
and is typically much higher (60–70%) in Germany, where self-monitoring is widely practiced.17
The reasons for this are not entirely clear, but reimbursement and patient motivation have been cited as possible reasons.3
This audit had several limitations. As this was an audit of a new service provision, no randomisation was performed. The patients who elected for routine anticoagulation clinic care were older than the self-monitoring patients and they may have been predisposed to poorer OAT control. The difference in testing intervals between the two groups makes comparison of %TIR problematic and the shorter interval between testing may have been contributory to the higher %TIR in the self-monitoring patients.
Self-monitoring of OAT has been shown to reduce the incidence of thrombotic and haemorrhagic complications18
and it may enhance the quality of life in some patients including those who travel frequently, who are in employment or education, and who find it difficult to travel to clinics.1
Although this study was not powered to assess the rate of adverse events, our data showed a trend towards reduced bleeding and thrombotic events in self-monitoring patients. While it is unlikely that self-monitoring of OAT will become cost effective compared to specialist anticoagulant clinics in the UK,1
the National Institute for health and Clinical Excellence recommends that patients with atrial fibrillation who require long-term anticoagulation should be considered for self-monitoring if preferred by the patient and eligibility criteria are met.19
Test-strips for self-monitoring are now available on the Drug Tariff, but several barriers to self-monitoring remain. Quality control (QC) preparations are not available on prescription and some patients are reluctant to perform QC, highlighting the importance of addressing the supply of QC preparations and a contract with the Trust specifying when QC testing should be undertaken. Many GPs refuse to prescribe test-strips and some Primary Care Trusts refuse to fund self-monitoring. The General Medical Services Contract National Enhanced Service is open to interpretation on issues surrounding funding of self-monitoring, which may limit progress on its implementation. Some patients see the price of the monitors as a major obstacle to self-monitoring.
We conclude that self-monitoring is acceptable to many patients if offered at the start of treatment and it is also efficacious. Our data suggest that a quarter of unselected patients referred for oral anticoagulation choose self-monitoring; they achieve a quality of oral anticoagulation comparable to that reported in previous UK clinical trials.
- Self-monitoring offered at the start of oral anticoagulation is associated with improved uptake and fewer dropouts.
- Outside trial conditions, self-monitoring patients achieve a quality of anticoagulant control, which may be superior to that attained in routine specialist anticoagulation clinics.