Self-testing of INR: Comparison to Traditional Testing

1. Self-testing of INR:Comparison to Traditional Testing Beatrice Leavel Nelson RN, BSN, MSN Candidate

2. PICO Question In Adults Receiving Oral Warfarin Therapy, What Is The Effect of Self Management on Therapeutic International Normalized Ratios Compared to Traditional Management?

3. Significance and Background Warfarin • the most commonly prescribed anticoagulant in the United States. • in the US during 2010, 32 million prescriptions were filled. • has a narrow therapeutic range.

4. Significance and Background Warfarin’s effectiveness is monitored by Internationalized Normalized Ratio (INR). Patients with an INR of <2 are at risk of forming thrombus or emboli, while patients with an INR>4.5 are at risk for bleeding.

5. Methods- Databases Used Research Articles published between 2000-2011 were searched using:

6. Methods-Search Terms

7. Methods Inclusion Criteria Exclusion Criteria Adult English language Human Must compare self monitoring to conventional management Must include outcome data on INR Other anticoagulant(s) were used Only self management or traditional management were studied Studies that only evaluated patient satisfaction

8. Methods After the search strategies were used the following emerged:

9. Methods

10. Findings Time Spent in Therapeutic Range Meta-analyses could not be pooled, but showed self-testing improved INR. The self-testing group showed improvement from 3.0% to 20.9% (Heneghan et al. ,2006). A significant difference in self-testing versus conventional management (95% CI, 2.7-5; p<0.001) (Matchar et al., 2010). The control arm spent 58.6% in therapeutic range while the self monitoring group spent 74% of time in range (p<0.001) (Ryan et al., 2009).

11. Findings (c0ntinued) Mean INR values were significantly lower in the control group, compared to the self-testing group (p<0.001). Self- management patients were more frequently in the target range (21% vs. 35%, p<0.001) (Eitz et al. 2008). One study with 78 participant had no statistical significance with INR values (McCahon et al. 2007). Overall, adult clients receiving warfarin therapy that self-monitor INRs spend more time in therapeutic range than those clients who have traditional management of INR.

12. Findings Adverse Events No significant differences between the two groups (Matchar et al. ,2010; Ryan et al.,2009) 4,723 patients showed a reduction in thromboembolic events of ½ in the self-monitoring group (RR 0.50, 95% CI, p<0.0001) and a decrease in major hemorrhages, minor hemorrhages were decreased significantly in the self-testing group (RR 0.64, 95% CI, p<0.00001) (Garcia-Alamino et al., 2010)

13. Findings (continued) No difference in bleeding, but the self-testing group had significantly lower thromboembolic events (p=0.008) (Eitz et al., 2008). A significant reduction in thromboembolic events (OR=0.45, 95% CI 0.30-0.68) and a significant reduction in major hemorrhages (0.65, 95% CI, 0.42-0.99) in the self- testing groups (Henegan et al., 2006). Overall, the self testing group demonstrated a reduction in thromboembolic events, but an equal or slight reduction is hemorrhages

14. Gaps, Limitations Reluctance of suitable patients to participate in the some of the trials For the meta-analyses some results could not be pooled due to differences in study methods The longest trial followed participants for only 2 years, perhaps a longer time, would provide additional information

15. Recommendations All patients on warfarin should be evaluated for and offered home monitoring when appropriate. ARNPs need to inform their client’s of evidence-based options available for care. Then if self-monitoring of INR is chosen, appropriate education needs to be provided to the client. National guidelines need to be formed for self-monitoring of INR through groups such as the American Heart Association or American College of Cardiology.

16. Conclusion The review of the literature demonstrates that home-monitored INR clients spend more time in therapeutic range, and have fewer adverse events. Beyond any reasonable doubt, home-monitoring of INRs is more effective that traditional monitoring of INRs in adult clients prescribed oral warfarin.