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This assessment is based on 26 RCTs evaluating the use of point-of-care devices for the self-monitoring (self-testing and self-management) of people receiving AOT. The results of this assessment indicate that:
l Self-monitoring (self-testing or self-management) of anticoagulation therapy leads to significantly fewer
thromboembolic events than standard primary care or anticoagulation control in specialised clinics
(RR 0.58, 95% CI 0.40 to 0.84; p= 0.004).
l There is no evidence of a difference in bleeding events (RR 0.95, 95% CI 0.74 to 1.21; p= 0.66).
l Self-monitoring almost halved the risk of thromboembolic events in people with AHVs.
l A statistically significantly greater reduction in thromboembolic events was observed among
self-managed people than among those in self-testing.
l Among people who self-monitored their therapy, there was a trend towards fewer thromboembolic
events when compared with those who were managed by their GPs or physicians than those managed in specialised anticoagulation clinic. The subgroup analysis was not, however, statistically significant.
l Self-monitoring significantly reduced the risk of mortality among people with AHVs but not among
those with mixed clinical indication. There was lower all-cause mortality through self-management but not through self-testing. In particular, significantly fewer deaths were observed among people who self-managed their AOT than those who received primary standard care (control care by a GP or a physician).
l Compared with standard care, self-monitoring (self-testing and self-management) did not demonstrate
a significant reduction in the number of major and minor bleeding events.
l In the majority of included trials (23 out of 26), the INR TTR was higher in self-monitoring people than
in people receiving standard anticoagulation control, and in five of these trials there was a statistically significant difference between intervention groups.
l The overall percentage of participants who completed self-monitoring was fairly high (at least 80%),
and in the few trials that collected participant views, participants expressed high satisfaction and willingness to continue with the intervention at home.
l Six of the trials were conducted in the UK and there was no evidence that the UK trial populations
were importantly different from the rest of the included studies.
l The majority of the trials (22 out of 26) investigated the use of the CoaguChek system, the results are,
therefore, more robust for CoaguChek than for ProTime and INRatio.
l Four of the 22 trials investigating the CoaguChek system used the CoaguChek XS system. There was
insufficient evidence to determine whether or not the CoaguChek XS outcomes differed from those for previous versions of CoaguChek systems.
l A brief overview of diagnostic performance of the various CoaguChek systems demonstrated that
across several studies INR results were more accurate in adults and children when comparing
CoaguChek XS with other CoaguChek models. We are of the opinion that this provides evidence that the clinical outcomes can be compared across different versions of the CoaguChek system.
Comparison with other studies
Our findings are in line with those of previously published systematic reviews on self-monitoring using point-of-care devices for the management of anticoagulation therapy, which found that self-monitoring was associated with a significantly lower incidence of thromboembolic events21,31,33,88,108,135–137
Cost-effectiveness
The base-case model assessed the impact on costs and outcomes of using self-monitoring to increase the number of INR tests performed annually (by 23), so as to improve INR control and prevent adverse outcomes. The primary findings are detailed below.
l While self-monitoring (50% self-testing, 50% self-management) is likely to increase the INR monitoring
cost compared with mixed primary/secondary care standard monitoring, it is likely to be cost-effective as a result of its impact on the incidence of thromboembolic events. This finding assumes that the pooled relative effects of self-testing and self-management, obtained from the meta-analysis of all RCTs, are applicable to the UK setting.
l Underlying this general observation is the finding that the pooled effect estimate for self-testing
on thromboembolic events is small and non-significant (RR 0.99), while the effect estimate for self-management is large (RR 0.51) and significant. Thus, within the base-case model,
self-management alone is highly cost-effective (or dominant), while self-testing is not cost-effective.
l In an alternative specification, the overall pooled effect estimates obtained from all self-testing and
self-management trials were applied to both the self-testing and self-management strategies in the model. Under this scenario, both self-testing and self-management, with CoaguChek XS or INRatio2, were found to be dominant or highly cost-effective compared with standard monitoring.
l Two key parameters underpinning the above findings are the baseline risk of thromboembolic events,
and the relative effect of self-monitoring on these events. The model findings were robust to individual changes in these parameters through feasible ranges. However, when the lower baseline risk of thromboembolic events was combined with the upper confidence limit for the RR for associated self-management (RR 0.69), the ICERs for self-monitoring as a whole rose above £30,000 per QALY. The same was found when the lower baseline risk of thromboembolic events was coupled with the upper confidence limit of the pooled RR for self-monitoring as whole (RR 0.89). It should be noted, however, that self-management on its own remained cost saving under the former combined scenario.
l Further uncertainty relates to the applicability of the pooled effect estimates to the UK setting. The few
identified UK-based trials of self-monitoring versus standard practice did not demonstrate significant effects on thromboembolic or bleeding events. Applying these effect estimates, self-monitoring would not be cost-effective at the self-monitoring testing frequency observed in RCTs.
l Alternative scenarios assessed the potential for self-monitoring to be cost-effective if used to replace
clinic-based testing without increasing the frequency of testing. Under these scenarios, it was assumed that there would be no effect on the number of thromboembolic or bleeding events and a cost-minimisation approach was adopted. This showed that when holding all other base-case parameters constant, self-monitoring (50% self-testing, 50% self-managing) was more costly than standard primary care monitoring, but less costly than standard secondary care monitoring. These findings were, however, sensitive to the unit costs applied to standard care monitoring visits. Applying
the alternative standard monitoring unit costs estimated by Jowett and colleagues,87the opposite was
observed, with self-monitoring dominating secondary care monitoring but being dominated by primary care monitoring.
Comparison with other economic evaluations
The findings of the model are generally consistent with those of previous evaluations, depending on the assumptions and input values applied. In line with previous models that have assumed or applied
significant reductions in thromoembolic events with self-management,33,82,84,86,88our model suggests
events. This in turn translates into more favourable estimates of cost-effectiveness. Further differences between the current analysis and the previous UK-based model include the application of higher standard secondary care monitoring costs, lower self-monitoring device costs (in line with current prices), and higher acute treatment costs for stroke and major bleeding events. Our analyses suggest that the
cost-effectiveness of self-monitoring is robust to variations in these parameters when pooled clinical effect estimates are applied.