Relationship between test frequency and outcomes of anticoagulation: a literature review and commentary with implications for the design of randomized trials of patient self-management

Safety and efficacy of using portable coagulation monitor for INR examination after left-sided mechanical prosthetic valve replacement

BACKGROUND

Time in therapeutic range (TTR) is an index to assess the effectiveness of anticoagulation and is important to predict the risk of bleeding and thrombosis in patients taking warfarin. In recent years, the portable coagulation monitor, a point-of-care testing device for patients to perform self-management international normalized ratio (INR) examination, has provided an opportunity to improve the quality of oral warfarin treatment. In this study, we applied TTR to evaluate the safety and efficacy of the portable coagulation monitor for patients with oral anticoagulant warfarin after left-sided mechanical prosthetic valve (MPV) replacement.

METHODS

It is a single-centre cohort study. From September 2019 to June 2021, a total of 243 patients who returned to our institution for outpatient clinic revisit at 3 months after left-sided MPV replacement, met the inclusion criteria and agreed to be followed up were included. Self-management group used portable coagulation monitor for INR examination, and patients in the conventional group had their INR monitored in routine outpatient visits. Clinical data of the patients would be recorded for the next 12 months, and results were compared between the two groups to assess the effect of the coagulation monitor on TTR and complications related to bleeding and thrombosis in patients with left-sided MPV replacement.

RESULTS

A total of 212 individuals provided complete and validated INR data spanning of 1 year. Those who applied the portable coagulation monitor had higher TTR values and larger number of tests for INR. No significant differences were seen between the two groups in postoperative bleeding and thromboembolic complications, but portable coagulation monitor showed a trend toward fewer bleeding events.

CONCLUSION

Portable devices for coagulation monitoring are safe and can achieve a higher TTR. Patients who use the portable coagulation monitor for home INR self-management can achieve a safe and effective warfarin therapy.

Comparative Effectiveness and Safety of Low-Dose Oral Anticoagulants in Patients With Atrial Fibrillation

Aims: Observational studies of various dose levels of direct oral anticoagulants (DOACs) for patients with atrial fibrillation (AF) found that a high proportion of patients received a dose lower than the target dose tested in randomized controlled trials. There is a need to compare low-dose DOACs with warfarin or other DOACs on effectiveness and safety. Methods: Using administrative data from Quebec province, Canada, we built a cohort of new warfarin or DOAC users discharged from hospital between 2011 and 2017. We determined CHA₂DS₂-VASc and HAS-BLED scores, and comorbidities for 3-year prior cohort entry. The primary effectiveness endpoint was a composite of ischemic stroke/systemic embolism (SE), and secondary outcomes included a safety composite of major bleeding (MB) events and effectiveness composite (stroke/SE, death) at 1-year follow-up. We contrasted each low-dose DOAC with warfarin or other DOACs as references using inverse probability of treatment weighting to estimate marginal Cox hazard ratios (HRs). Results: The cohort comprised 22,969 patients (mean age: 80-86). We did not find a significant risk reduction for the stroke/SE primary effectiveness endpoint for DOACs vs. warfarin; however, we observed a significantly lower risk for low-dose dabigatran vs. warfarin (HR [95%CI]: 0.59 [0.42-0.81]) for effectiveness composite, mainly due to a lower death rate. The differences in effectiveness and safety composites between low-dose rivaroxaban vs. warfarin were not significant. However, low-dose apixaban had a better safety composite (HR: 0.68 [0.53-0.88]) vs. warfarin. Comparisons of dabigatran vs. apixaban showed a lower risk of stroke/SE (HR: 0.53 [0.30-0.93]) and a 2-fold higher risk of MB. The MB risk was higher for rivaroxaban than for apixaban (HR: 1.58 [1.09-2.29]). Conclusions: The results of this population-based study suggest that low-dose dabigatran has a better effective composite than warfarin. Compared with apixaban, low-dose dabigatran had a better effectiveness composite but a worse safety profile. Low-dose apixaban had a better safety composite than warfarin and other low-dose DOACs. Given that the comparative effectiveness and safety seem to vary from one DOAC to another, pharmacokinetic data for specific populations are now warranted.

Evaluation of a Pharmacist-Led Remote Warfarin Management Model Using a Smartphone Application (Yixing) in Improving Patients' Knowledge and Outcomes of Anticoagulation Therapy

Background: The management of warfarin-treated patients has been recognized as a challenge due to narrow therapeutic range and food and drug interactions in warfarin therapy. We aim to evaluate the effect of a pharmacist-led remote warfarin management model using a smartphone application (app) on anticoagulation therapy.

Methods: Eligible patients who had received warfarin therapy after mechanical heart valve replacement were enrolled. The intervention group was offered a pharmacist-led remote warfarin management model using the app named Yixing. Yixing incorporates functions including automatic daily reminder, personal health record, educational program, and online counseling. The control group received traditional pharmacy services without Yixing. Co-primary outcomes were patients’ awareness score of warfarin therapy obtained from questionnaire, the medication adherence measured by the percentage of the correct-warfarin-taken days in the monitored period, the fraction of time in therapeutic range (FTTR), and the incidence of anticoagulation-related complications. The needed information of the patients was acquired via electronic medical records from the hospital, Yixing system and telephone follow-up when necessary.

Results: 64 and 66 patients were initially in the intervention and control groups respectively. After propensity score matching, 50 patients were assigned in each group. The intervention group had a median age of 51.0 years, in which 27 (54%) were male. The control group had a median age of 50.5 years, in which 28 (56%) were male. Patient awareness score in the intervention group was 8.00 (2.00), which was higher than that in the control group, with score at 6.50 (2.50) (p = 0.001). No significant difference was found in the percentage of the correct-warfarin-taken days between the two groups (p = 0.520). The median (interquartile range) value of FTTR was 80.3% (21.9%) and 72.1% (17.7%) in the intervention and control groups respectively (p = 0.033), and no significant differences in the incidence of anticoagulation-related complications were observed (p = 0.514).

Conclusion: The pharmacist-led remote warfarin management model using Yixing improves patients’ awareness of warfarin therapy and increases FTTR, but may not have significant improvements on medication adherence and safety.

Quality of life in patients with nonvalvular atrial fibrillation treated with oral anticoagulants

OBJECTIVES

Health-related quality of life (HRQL) is a key factor in making anticoagulant treatment decisions. The objective of this study was to assess the HRQL of patients with nonvalvular atrial fibrillation by treatment type: direct oral anticoagulants (DOACs) or vitamin K antagonists (VKAs).

METHODS

We carried out a cross-sectional observational study with clinical practice data, gathering demographic and clinical variables. HRQL was measured using the 5-level 5-dimension EuroQol questionnaire (EQ-5D-5L). Differences between the study groups in HRQL as measured by the EQ-5D-5L were analyzed using two-part multivariate regression models. First, using logistic regression, the adjusted probability, p(x), of having perfect health was estimated in each subgroup. Secondly, generalized linear models were used to estimate mean disutility values, w(x), in a population that does not have perfect health, i.e. utility less than 1 or 1-w(x).

RESULTS

We recruited 333 patients, of whom 126 were on DOACs and 207 on VKAs. A significant difference was observed in the EQ-5D-5L anxiety/depression dimension, with a higher percentage of patients classified in the 'no problems' category in the DOAC group. The same type of analysis did not identify significant differences in any of the other dimensions (mobility, self-care, usual activities or pain/discomfort).

DISCUSSION

In the multivariate model, utility was significantly higher in the DOAC group than in the VKA group, although the difference was small (0.0121). This difference is attributable to patients on DOACs having less anxiety/depression.

CONCLUSION

Patients treated with DOACs report a slightly better quality of life than those treated with VKAs.

Health-related quality of life correlates with time in therapeutic range in children on anticoagulants with International Normalised Ratio self-monitoring

BACKGROUND

Managing oral anticoagulant therapy with vitamin K antagonists remains challenging in paediatric medicine.

AIMS

This study aimed to assess the correlation between time in therapeutic range and quality of life in children participating in a non-selective International Normalised Ratio self-monitoring and vitamin K antagonist education programme.

METHODS

Children aged from 2 to 18 years and receiving vitamin K antagonist therapy were eligible for this prospective multicentre study. Clinical and demographic data were collected. Health-related quality of life was assessed using the PedsQL™ 4.0 questionnaire. Correlations between quality of life scores and time in therapeutic range were measured.

RESULTS

A total of 121 children were included in the study (mean age 9.6±4.9 years). Cardiac conditions were the predominant indication for vitamin K antagonists. The mean time in therapeutic range was 0.78±0.15 overall, and 0.76±0.24 over the 3-month period before quality of life assessment. The mean total quality of life score was 76.2±18 in self reports, 71.4±22 in mother reports and 73.5±19 in father reports. The time in therapeutic range correlated with the total quality of life scores in self reports (r=0.22; P=0.04), mother reports (r=0.23; P=0.02) and father reports (r=0.28; P=0.02). The time in therapeutic range predominantly correlated with school functioning in self reports (r=0.38; P=0.002) and mother reports (r=0.40; P<0.001), and with physical functioning in father reports (r=0.28; P=0.03).

CONCLUSIONS

Time in therapeutic range correlated with quality of life in children participating in a non-selective International Normalised Ratio self-monitoring and vitamin K antagonist education programme. Regular assessment of quality of life in patient education programmes contributes towards understanding the concerns and needs of patients.

The Effect of Warfarin Administration Time on Anticoagulation Stability (INRange): A Pragmatic Randomized Controlled Trial

PURPOSE

Without supporting evidence, clinicians commonly recommend that warfarin be taken in the evening. We conducted a randomized controlled trial to evaluate the effect of administration time (morning vs evening) on the stability of warfarin's anticoagulant effect.

METHODS

A total of 236 primary care physicians serving 54 western Canadian communities mailed letters of invitation to all their warfarin-using patients. Eligible patients were community-dwelling warfarin users (any indication) with at least 3 months of evening warfarin use and no plans for discontinuation. Participants were randomized (by web-based allocation) to morning vs continued evening warfarin ingestion. We used the Rosendaal method to determine the proportion of time within therapeutic range (TTR) of the international normalized ratio (INR) blood test month 2 to 7 postrandomization vs the 6 months prerandomization. The primary outcome was the percent change in proportion of time outside target INR range (with an a priori minimum clinically important difference of ±20%). All analyses were intention to treat.

RESULTS

Between March 8, 2015 and September 30, 2016, we randomized 109 participants to morning and 108 to evening warfarin use. TTR rose from 71.8% to 74.7% in the morning group, and from 72.6% to 75.6% in the evening group, for a change in TTR of 2.9% in the former vs 3.0% in the latter (difference, -0.1%; P = .97; 95% CI for the difference, -6.1% to 5.9%). The difference in percent change in proportion of time outside the therapeutic INR range (obtained via Hodges-Lehmann estimation of the difference in medians) was 4.4% (P = .62; 95% CI for the difference, -17.6% to 27.3%).

CONCLUSIONS

Administration time has no statistically significant nor clinically important impact on the stability of warfarin's anticoagulant effect. Patients should take warfarin whenever regular compliance would be easiest.

Assessment of agreement and time in therapeutic range of capillary versus venous international normalised ratio in frail elderly people in a nursing home

Vitamin K antagonists are widely used, yet have a slim therapeutic margin and high iatrogenicity. Patients are monitored through international normalised ratio (INR) by venipuncture, but coagulometers could measure INR by capillary puncture. This prospective study evaluated the clinical concordance of capillary INR versus venous INR in 31 nursing home patients. Concordance was good and mean time in therapeutic range (TTR) markedly increased. Capillary INR is thus reliable, could improve TTR and decrease iatrogenicity.

Cost of Healthcare Associated With Deep Vein Thrombosis in Patients Treated With Warfarin in Turkey: 2010-2013 Database Analysis of a Tertiary Care Center

OBJECTIVES

To evaluate the cost of healthcare with respect to the quality of anticoagulation in patients with deep vein thrombosis (DVT) treated with warfarin in daily practice via the database analysis of a tertiary care center in the period 2010 to 2013.

METHODS

Of 258 307 records in total, 42 582 unique patients with DVT and 32 012 patients with international normalized ratio (INR) measurements were included. Overall, 6720 unique patients with DVT diagnosis and one or more INR measurements were identified, and the records of 4377 out of 6720 unique patients were validated and included in the analysis data set. The cost analysis was based on direct medical costs from the payer's perspective. Cost items were related to healthcare resource utilization (inpatient and outpatient services) during the study period, which provided a basis for calculation of per-patient, outpatient, inpatient, and total direct medical costs.

RESULTS

Mean outpatient, inpatient, and total hospital admission costs were $578, $2195, and $2785, respectively, for patients with time in the therapeutic range of 70% or more, whereas the same costs were $571, $2163, and $3192, respectively, for patients with time in the therapeutic range of less than 70%.

CONCLUSIONS

Our findings for a retrospective cohort of patients with DVT undergoing warfarin therapy reveal that patients spent 70% or more, as opposed to less than 70%, of follow-up time within the therapeutic INR range and that outpatient care, as opposed to inpatient care, was associated with lower healthcare costs. Given the significant contribution that hospital stay makes to the cost burden of DVT, our findings also highlight the association between poor warfarin anticoagulant control and increased hospitalization costs.

Retrospective cohort study for evaluating the INR monitoring patterns in patients with deep vein thrombosis in daily practice: Analysis of 2010-2013 database of a tertiary care center

OBJECTIVE

To evaluate the international normalized ratio (INR) monitoring patterns in patients with deep vein thrombosis.

METHODS

Of 32,012 patients with ≥1 outpatient INR measurement and 42,582 patients with confirmed deep vein thrombosis diagnosis registered to our hospital between 1 January 2010 and 31 December 2013, 6720 records were identified to have both deep vein thrombosis and international normalized ratio measurement, and 4.377 out of 6.720 single patient records were determined to be statistically analyzable.

RESULTS

Median INR measurement frequency was 6.47 times/year and patients had INR levels of 2-3 in 34.3% of follow-up time. Having ≥70% vs. <70% of follow-up time within therapeutic range was associated with lower hospital admission frequency (9.7 vs. 10.3 times/year).

CONCLUSION

Our study revealed only one-third of the follow-up time to be spent within therapeutic INR, association of INR therapeutic range with lesser number of hospital admissions and INR monitoring frequency of 6.47 times/year despite lack of stable INR control in most of the deep vein thrombosis patients.

Hospital pharmacist intervention improves the quality indicator of warfarin control: A retrospective cohort study

Background/Aims Our previous study showed that time in therapeutic range (TTR) control of warfarin therapy was negatively affected in non-valvular atrial fibrillation (NVAF) patients with heart failure. This study assesses the effect of intervention by hospital pharmacists on TTR control in Japanese NVAF patients with heart failure. Method This retrospective cohort study included NVAF patients with heart failure admitted and discharged from the cardiovascular internal medicine ward between March 2011 and July 2013. Participants were classified into two groups according to the instructions by hospital pharmacists and physicians (Intervention group) and by physicians only (Usual care group). The primary outcome was TTR. Secondary outcomes were major bleeding and minor bleeding. Results In total, 57 participants (35 males, 22 females; mean age: 69.7 years) were classified into the Intervention (n = 25) and Usual care (n = 32) groups. TTR within-therapeutic range was significantly higher and within sub-therapeutic range was significantly lower in the Intervention than the Usual care group. Major bleeding and minor bleeding were not significantly different between the two groups. Conclusion The intervention of hospital pharmacists with anticoagulation therapy can lead to proper use of warfarin, which can be useful when physicians prescribe warfarin. J. Med. Invest. 64: 266-271, August, 2017.

Impact of regular physical activity on weekly warfarin dose requirement

Warfarin is an oral anticoagulant agent with a narrow therapeutic index. There is a marked inter- and intra-patient variability in warfarin dose requirement. All factors influencing warfarin response are not known and this study aims to evaluate if regular physical activity (RPA) is a determining factor. RPA level was collected with the Stanford Brief Activity Survey in 1064 incident warfarin users, as part of the Quebec Warfarin Cohort (QWC), and with the Global Physical Activity Questionnaire in 618 patients from the Montreal Heart Institute (MHI) Biobank. Linear regression was performed to model relationship of warfarin dose after 3 months of therapy in the QWC with RPA, while controlling for height, weight, age, CYP2C9 (*2 and *3 alleles) and VKORC1 (*2 allele) genotype. Warfarin dose of prevalent users was modeled in the MHI Biobank for replication. A higher level of physical activity was associated with higher doses of warfarin in both cohorts. In the QWC, physical activity could explain 5.4 % (P < 0.001) and 0.9 % (P = 3.23 × 10⁻⁵) of variance in dose, in univariate and multivariable models, respectively. Similarly, RPA was found to be associated with 1.7 % (P = 0.0012) and 0.5 % (P = 0.0391) of inter-individual variability in warfarin dose requirement before and after adjustment for other covariables, respectively. RPA is associated with higher warfarin dose requirement. The relevance of clinical recommendations on RPA to maintain a steady response to warfarin should be assessed in further studies.

At-Home Versus In-Clinic INR Monitoring: A Cost-Utility Analysis from The Home INR Study (THINRS)

BACKGROUND

Effective management of patients using warfarin is resource-intensive, requiring frequent in-clinic testing of the international normalized ratio (INR). Patient self-testing (PST) using portable at-home INR monitoring devices has emerged as a convenient alternative. As revealed by The Home INR Study (THINRS), event rates for PST were not significantly different from those for in-clinic high-quality anticoagulation management (HQACM), and a cumulative gain in quality of life was observed for patients undergoing PST.

OBJECTIVE

To perform a cost-utility analysis of weekly PST versus monthly HQACM and to examine the sensitivity of these results to testing frequency.

PATIENTS/INTERVENTIONS

In this study, 2922 patients taking warfarin for atrial fibrillation or mechanical heart valve, and who demonstrated PST competence, were randomized to either weekly PST (n = 1465) or monthly in-clinic testing (n = 1457). In a sub-study, 234 additional patients were randomized to PST once every 4 weeks (n = 116) or PST twice weekly (n = 118). The endpoints were quality of life (measured by the Health Utilities Index), health care utilization, and costs over 2 years of follow-up.

RESULTS

PST and HQACM participants were similar with regard to gender, age, and CHADS2 score. The total cost per patient over 2 years of follow-up was $32,484 for HQACM and $33,460 for weekly PST, representing a difference of $976. The incremental cost per quality-adjusted life year gained with PST once weekly was $5566 (95 % CI, -$11,490 to $25,142). The incremental cost-effectiveness ratio (ICER) was sensitive to testing frequency: weekly PST dominated PST twice weekly and once every 4 weeks. Compared to HQACM, weekly PST was associated with statistically significant and clinically meaningful improvements in quality of life. The ICER for weekly PST versus HQACM was well within accepted standards for cost-effectiveness, and was preferred over more or less frequent PST. These results were robust to sensitivity analyses of key assumptions.

CONCLUSION

Weekly PST is a cost-effective alternative to monthly HQACM and a preferred testing frequency compared to twice weekly or monthly PST.

Direct Oral Anticoagulants for Very Elderly People With Atrial Fibrillation

Background:

Four direct oral anticoagulants (DOACs) have been licensed for the treatment of atrial fibrillation (AF); efficacy and safety have been shown in clinical trials, but its real use in elderly and very elderly people is still unclear.

Aim:

To evaluate the impact of DOACs in our patients (pts) aged ≥75 years and switched from other treatments.

Methods:

From September 2013 to May 2015, all consecutive pts aged ≥75 years, males and females, in treatment for AF and switched to DOACs are considered in this study. Follow-up (FU) was scheduled after 3 and 6 months by phone and after 12 months by visit.

Results:

Two hundred thirty-two pts in treatment for AF were switched to DOACs, among these 143 (61.6%) pts aged ≥75 years (mean age, 81 years). The medium FU was 9.6 months, during which 4 minor bleedings in 4 different pts and 1 clinically relevant nonmajor bleeding were reported, all treated with temporary cessation or reduction in DOACs. Two strokes occurred in pts in treatment with dabigatran 110 mg, both resolved without serious sequelae; 2.8% of pts had nausea, itching, vomiting, or discomfort, half of these returned to acenocumarol, and the remaining switched to other DOAC. Four pts died, but the deaths were not related to anticoagulation.

Conclusion:

As reported for general people, also in our elderly population, DOACs resulted in a good alternative to old antithrombotic therapies. Efficacy and safety associated with a higher compliance by pts bring these drugs to be the first choice for long-term anticoagulation.

Evaluation of SAMe-TT2R2 score and other clinical factors influencing the quality of anticoagulation therapy in non-valvular atrial fibrillation: a nationwide study in Spain

OBJECTIVE

To assess the major clinical factors affecting the quality of anticoagulation and evaluate the predictive value of the SAMe-TT2R2 score to identify patients who will achieve a high average time in therapeutic range (T.T.R.) with vitamin K antagonist (V.K.A.) treatment.

RESEARCH DESIGN AND METHODS

This observational, cross-sectional, retrospective and nationwide multicenter study included 1524 patients from the primary care setting with non-valvular atrial fibrillation receiving V.K.A. (≥12 months). We performed a bivariate analysis to identify factors individually associated with the T.T.R. and a multiple regression analysis to identify the independent predictive factors. For the validation of the SAMe-TT2R2 score, the receiver operating characteristic (R.O.C.) curve was calculated and the Hosmer-Lemeshow test was used to test calibration.

RESULTS

A total of 94.8% of patients received acenocumarol (4.8% warfarin). A progressive decrease in mean T.T.R. was found when the SAMe-TT2R2 score increased from 0 points (72.1 ± 17.1%) to 4 points (64.1 ± 23.2%), p < 0.001. Other risk scores (CHADS2 and CHA2DS2-VASc, HAS-BLED) were also associated with the mean T.T.R. We found a significant association between low T.T.R. and the following clinical factors: female sex, three or more comorbidities, amiodarone treatment, dietary habits, bleeding history and the intake of ≥7 tablets per day besides V.K.A. (p < 0.01). Regarding SAMe-TT2R2 score validation, the R.O.C. curve showed significant capability, although not high, of discriminating good anticoagulation control (T.T.R. ≥65%) with an area under the curve of 0.562 (95% C.I. 0.533-0.592, p < 0.001) which increased, remaining modest, to 0.594 (95% C.I. 0.564-0.624, p < 0.001) when the factors not included in SAMe-TT2R2 score were added.

CONCLUSION

In this cohort, the SAMe-TT2R2 score had a significant, although modest, ability to assess the likelihood of good international normalized ration (I.N.R.) control, and its predictive value might slightly improve by adding other simple clinical factors. Further research is needed to refine the predictive scales.

Effects of anticoagulation provider continuity on time in therapeutic range for warfarin patients

Anticoagulation (AC) clinics use the percentage of time in the therapeutic INR range (%TTR) to characterize the quality of management for patients treated with warfarin. In order to guide policy and procedure changes, the purpose of this quality improvement (QI) study was to characterize the AC patient population at The Johns Hopkins Hospital (JHH). We set out to investigate the impact of AC clinic provider continuity on the quality of anticoagulation management. This QI study is a retrospective chart review of 525 warfarin patients managed by pharmacists in the Hematology AC Management Clinic at JHH from June 28, 2013 to November 1, 2014. We recorded patient demographic and clinical characteristics and the quality of AC management using %TTR, and compared these parameters between patients with (Group A) and without a primary AC (Group B). Group A patients had a significantly higher %TTR than Group B patients (53.2 vs. 46.5 %, p = 0.008). In conclusion, we found that patients with a primary AC clinic provider had a higher %TTR than patients with multiple providers. If confirmed prospectively, this approach to warfarin management could represent one technique for AC clinics to optimize patient management and clinical outcomes.

The impact of frequency of patient self-testing of prothrombin time on time in target range within VA Cooperative Study #481: The Home INR Study (THINRS), a randomized, controlled trial

Anticoagulation (AC) is effective in reducing thromboembolic events for individuals with atrial fibrillation (AF) or mechanical heart valve (MHV), but maintaining patients in target range for international normalized ratio (INR) can be difficult. Evidence suggests increasing INR testing frequency can improve time in target range (TTR), but this can be impractical with in-clinic testing. The objective of this study was to test the hypothesis that more frequent patient-self testing (PST) via home monitoring increases TTR. This planned substudy was conducted as part of The Home INR Study, a randomized controlled trial of in-clinic INR testing every 4 weeks versus PST at three different intervals. The setting for this study was 6 VA centers across the United States. 1,029 candidates with AF or MHV were trained and tested for competency using ProTime INR meters; 787 patients were deemed competent and, after second consent, randomized across four arms: high quality AC management (HQACM) in a dedicated clinic, with venous INR testing once every 4 weeks; and telephone monitored PST once every 4 weeks; weekly; and twice weekly. The primary endpoint was TTR at 1-year follow-up. The secondary endpoints were: major bleed, stroke and death, and quality of life. Results showed that TTR increased as testing frequency increased (59.9 ± 16.7 %, 63.3 ± 14.3 %, and 66.8 ± 13.2 % [mean ± SD] for the groups that underwent PST every 4 weeks, weekly and twice weekly, respectively). The proportion of poorly managed patients (i.e., TTR <50 %) was significantly lower for groups that underwent PST versus HQACM, and the proportion decreased as testing frequency increased. Patients and their care providers were unblinded given the nature of PST and HQACM. In conclusion, more frequent PST improved TTR and reduced the proportion of poorly managed patients.

Anticoagulation in Atrial Fibrillation

Patients with atrial fibrillation (AF) are at increased thromboembolic risk, and they suffer more severe strokes with worse outcomes. Most thromboembolic complications of AF are eminently preventable with oral anticoagulation, and the increasing numbers of AF patients mean antithrombotic therapy is the most crucial management aspect of this common arrhythmia. Despite the proven efficacy of warfarin, a string of limitations have meant that it is underused by physicians and patients alike. This has prompted a search for new anticoagulants that could overcome many of the inconveniences of dose variability and anticoagulant monitoring associated with warfarin, but without sacrificing efficacy in thromboprophylaxis. The arrival of new oral anticoagulants has been complemented by improved risk stratification schemes, which permit clinicians to easily and reliably identify patients requiring anticoagulation and their bleeding risk. These advances in AF treatment will hopefully translate into improved outcomes for patients, especially as our experience with the new agents grows.

Cost-effectiveness analysis of dabigatran and anticoagulation monitoring strategies of vitamin K antagonist

BACKGROUND

Vitamin K antagonists are commonly used for the prevention of thromboembolic events. Patient self-monitoring of vitamin K antagonists has proved superior to usual care. Dabigatran has been shown, relative to warfarin, to reduce thromboembolic events without increasing bleeding.

METHODS

We constructed a Markov model to compare vitamin K self-monitoring strategies to dabigatran including effectiveness and costs of monitoring and complications (thromboembolism and major bleeding). The model was used to project the incidence of these complications, life years, quality-adjusted life years, and health system costs with anticoagulant treatment throughout life. The analysis was conducted from the health system perspective and from the societal perspective.

RESULTS

Low quality evidence suggests that self-monitoring is at least as effective as dabigatran for the outcomes of thrombosis, bleeding and death. Moderate quality evidence that patient self-monitoring is more effective than other forms of monitoring degree of anticoagulation with vitamin K antagonists, reducing the relative risk of thromboembolism by 41% and death by 34%. The cost per quality adjusted year gained relative to other warfarin monitoring strategies is well below 30,000 € in the short term, and is a dominant alternative from the fourth year. In comparison with dabigatran, the lower annual cost and its equivalence in terms of effectiveness made self-monitoring the dominant option. These results were confirmed in the probabilistic sensitivity analysis.

CONCLUSIONS

We have moderate quality evidence that self-monitoring of vitamin K antagonists is a cost-effective alternative compared with hospital and primary care monitoring, and low quality evidence, compared with dabigatran. Our analyses contrast with the available cost analysis of dabigatran and usual care of anticoagulated patients.

Self-management of warfarin therapy

BACKGROUND

Clinical studies from other countries show that self-management of warfarin therapy may reduce the risk of mortality, thromboembolism and complications when compared to conventional therapy. The purpose of this study was to train patients in self-management and compare the results with conventional therapy in Norway.

METHOD

A total of 23 patients who had previously been given conventional therapy by their GPs were instructed in how to measure INR (using the CoaguChek XS device) and administer warfarin dosage through a structured training programme over the course of 27 weeks. The participants continued with self-management for a further 28 weeks after the end of the training period. The time in the therapeutic range (TTR, measured as a percentage) was calculated and the TTR for conventional therapy and self-management were compared.

RESULTS

No significant difference in average TTR was found when comparing conventional therapy (70% (95% confidence interval (CI) 62-78)) with the self-management period (75% (95% CI 69-81, p = 0.24)). The percentage of extreme INR values (< 1.5 or > 5.0) was higher during conventional therapy than during self-management (6.8% vs. 1.0%, p < 0.001).

INTERPRETATION

No significant difference in TTR was found when comparing self-management and conventional warfarin therapy in our study, but for self-management there was a lower percentage of extreme INR values compared to conventional warfarin therapy.

Effective and Safe Management of Oral Anticoagulation Therapy in Patients Who Use the Internet-Accessed Telecontrol Tool SintromacWeb

Background

Despite the existing evidence that highlights the benefits of oral anticoagulation therapy (OAT) self-testing and self-management by patients in comparison with conventional control, significant progress is still needed in the implementation of computer-based, Internet-assisted systems for OAT within health care centers. The telecontrol tool “SintromacWeb” is a previously validated system for OAT management at home, which is currently operative and accessed by patients through a hospital Web portal.

Objective

The intent of the study was to assess the effectiveness and safety of OAT management in patients using the SintromacWeb telecontrol system in reference to control in patients using the conventional system (management at the hematology department), in terms of time in therapeutic range (TTR) of International Normalized Ratio (INR).

Methods

In this observational prospective study, patients were identified by their physician and divided in two groups according to the OAT management system that they were already using (conventional control or telecontrol with SintromacWeb). For 6 months, patients were required to visit the hematology department every time their physician considered it necessary according to usual clinical practice. Sociodemographic and clinical variables for the study were collected at first visit (baseline) and at those visits closest to 2, 4, and 6 months after first visit.

Results

A total of 173 patients were evaluated, 87 with conventional control and 86 with telecontrol. Follow-up time was a median of 6.3 (range 5.2-8.1) months. The average time of OAT treatment prior to enrollment was 9.2 (SD 6.4) years. Patients in the telecontrol group tested their INR a median of 21 (range 4-22) days versus a median of 35 (range 14-45) days in patients in the conventional control group (P<.001). TTR in the telecontrol group was 107 (SD 37) days versus 94 (SD 37) days in the conventional control group (an increase of 12.6%; P=.02). In all visits, the percentage of TTR was higher in the telecontrol group (at the third visit: 59% vs 48%; P=.01). Higher TTR (positive coefficient) was associated with patients under OAT telecontrol (P=.03). Under-anticoagulation (INR<1.5) and over-anticoagulation (INR>5) were observed in 34 (19.7%, 34/173) and 38 (22.0%, 38/173) patients, respectively (no differences between treatment groups). Seven thrombotic and/or bleeding events were serious, 12 were non-serious, and most of them (5 and 10, respectively) occurred in the conventional control group.

Conclusions

In clinical practice, OAT management with the Internet-based tool SintromacWeb is effective and safe for those patients who are eligible for OAT telecontrol.

Quality of oral anticoagulation with phenprocoumon in regular medical care and its potential for improvement in a telemedicine-based coagulation service--results from the prospective, multi-center, observational cohort study thrombEVAL

BACKGROUND

The majority of studies on quality of oral anticoagulation (OAC) therapy with vitamin K-antagonists are performed with short-acting warfarin. Data on long-acting phenprocoumon, which is frequently used in Europe for OAC therapy and is considered to enable more stable therapy adjustment, are scarce. In this study, we aimed to assess quality of OAC therapy with phenprocoumon in regular medical care and to evaluate its potential for optimization in a telemedicine-based coagulation service.

METHODS

In the prospective observational cohort study program thrombEVAL we investigated 2,011 patients from regular medical care in a multi-center cohort study and 760 patients from a telemedicine-based coagulation service in a single-center cohort study. Data were obtained from self-reported data, computer-assisted personal interviews, and laboratory measurements according to standard operating procedures with detailed quality control. Time in therapeutic range (TTR) was calculated by linear interpolation method to assess quality of OAC therapy. Study monitoring was carried out by an independent institution.

RESULTS

Overall, 15,377 treatment years and 48,955 international normalized ratio (INR) measurements were analyzed. Quality of anticoagulation, as measured by median TTR, was 66.3% (interquartile range (IQR) 47.8/81.9) in regular medical care and 75.5% (IQR 64.2/84.4) in the coagulation service (P <0.001). Stable anticoagulation control within therapeutic range was achieved in 63.8% of patients in regular medical care with TTR at 72.1% (IQR 58.3/84.7) as compared to 96.4% of patients in the coagulation service with TTR at 76.2% [(IQR 65.6/84.7); P = 0.001)]. Prospective follow-up of coagulation service patients with pretreatment in regular medical care showed an improvement of the TTR from 66.2% (IQR 49.0/83.6) to 74.5% (IQR 62.9/84.2; P <0.0001) in the coagulation service. Treatment in the coagulation service contributed to an optimization of the profile of time outside therapeutic range, a 2.2-fold increase of stabile INR adjustment and a significant decrease in TTR variability by 36% (P <0.001).

CONCLUSIONS

Quality of anticoagulation with phenprocoumon was comparably high in this real-world sample of regular medical care. Treatment in a telemedicine-based coagulation service substantially improved quality of OAC therapy with regard to TTR level, frequency of stable anticoagulation control, and TTR variability.

TRIAL REGISTRATION

ClinicalTrials.gov, unique identifier NCT01809015, March 8, 2013.

Pharmacist-managed international normalized ratio patient self-testing is associated with increased time in therapeutic range in patients with left ventricular assist devices at an academic medical center

Patients with left ventricular assist devices (LVADs) are at increased risk of bleeding and thrombotic complications making warfarin therapy particularly challenging. Patient self-testing (PST) using point-of-care international normalized ratio (INR) devices has shown favorable outcomes in other populations, but the use of PST in LVAD patients has not been well described. The purpose of this study was to evaluate the effectiveness of pharmacist-managed INR PST versus usual care (UC) in patients with LVADs at a single center. We performed a retrospective cohort study of adult patients (in a 1:4 ratio PST versus UC) implanted with an LVAD (HeartMate II or HVAD) treated with warfarin from January 1, 2007, to January 31, 2013. We reviewed all INRs and bleeding/thrombotic events in LVAD patients whose anticoagulation was managed by clinical pharmacists via INR PST versus UC and calculated a percent time in therapeutic range (%TTR) by Rosendaal method. Fifty-five patients were studied. Demographic data were generally similar between the cohorts. Mean %TTR was higher in the PST cohort versus UC (44.4% vs. 30.6%, p = 0.026). There was no difference in the rate per patient-year of bleeding (0.23 vs. 0.33, p = 0.55) or thrombotic events (0.12 vs. 0.13, p = 0.88). Pharmacist-managed INR PST is associated with an increased %TTR in patients with LVADs.

Pharmacogenetic-guided selection of warfarin versus novel oral anticoagulants for stroke prevention in patients with atrial fibrillation: a cost-effectiveness analysis

OBJECTIVES

To compare clinical and economic outcomes of two anticoagulation therapy strategies, (i) pharmacogenetic-guided selection (PG-AC) of warfarin versus novel oral anticoagulants (NOACs), and (ii) usual anticoagulation care (usual AC) in patients with atrial fibrillation (AF), from the perspective of US healthcare payers.

METHODS

A Markov model was used to simulate long-term outcomes in a hypothetical cohort of 65-year-old patients with newly diagnosed AF: (i) all usual AC patients received warfarin therapy, and (ii) all PG-AC patients were genotyped. Patients with normal warfarin sensitivity genotypes would receive warfarin. Patients with high or low warfarin sensitivity genotypes would receive NOAC. Model inputs were derived from clinical trials published in the literature. The outcome measure was incremental cost per quality-adjusted life-year (QALY) gained (ICER).

RESULTS

PG-AC gained higher QALYs with higher cost (9.912 QALYs and USD94 396) when compared with usual AC (9.721 QALYs and USD93 853) in base-case analysis. The ICER of PG-AC was 2843 USD/QALY. The ICER of PG-AC would exceed 50 000 USD/QALY if the monthly cost of NOAC was more than USD285 or the risk of stroke with NOAC versus warfarin was more than 0.93. In 10 000 Monte Carlo simulations, PG-AC was cost-effective 96.4% of the time and usual AC was cost-effective 3.6% of the time. PG-AC was more costly than usual AC with a mean cost difference of USD1927 (95% confidence interval 1.877-1.977, P<0.001), and gained higher QALYs by 0.209 (95% confidence interval 0.208-0.210, P<0.001).

CONCLUSION

Compared with warfarin therapy with time in therapeutic range of 60%, using genotype to triage AF patients to warfarin or NOAC appears to be highly cost-effective.

New oral anticoagulants in patients with nonvalvular atrial fibrillation: a review of pharmacokinetics, safety, efficacy, quality of life, and cost effectiveness

Atrial fibrillation (AF) continues to be a leading cause of cerebrovascular morbidity and mortality resulting from cardioembolic stroke. Oral anticoagulation therapy has been shown to decrease the incidence of cardioembolic stroke in patients with AF by more than 50%. Appropriate use of anticoagulation with vitamin K antagonists requires precise adherence and monitoring. A number of factors that potentially induce patients’ dissatisfaction reduce quality of patient life. New direct oral anticoagulants, such as the direct factor Xa inhibitors rivaroxaban, apixaban, edoxaban, and the thrombin inhibitor dabigatran, were developed to overcome the limitations of the conventional anticoagulant drugs. However, models to optimize the benefit of therapy and to ensure that therapy can be safely continued are missing for the new oral anticoagulants. This review will briefly describe the new oral anticoagulants dabigatran, rivaroxaban, apixaban, and edoxaban with focus on their use for prevention of embolic events in AF. Moreover, it will discuss the safety, efficacy, cost data, and benefit for patients’ quality of life and adherence.

Relationship between time in therapeutic range and comparative treatment effect of rivaroxaban and warfarin: results from the ROCKET AF trial

BACKGROUND

Time in therapeutic range (TTR) is a standard quality measure of the use of warfarin. We assessed the relative effects of rivaroxaban versus warfarin at the level of trial center TTR (cTTR) since such analysis preserves randomized comparisons.

METHODS AND RESULTS

TTR was calculated using the Rosendaal method, without exclusion of international normalized ratio (INR) values performed during warfarin initiation. Measurements during warfarin interruptions >7 days were excluded. INRs were performed via standardized finger-stick point-of-care devices at least every 4 weeks. The primary efficacy endpoint (stroke or non-central nervous system embolism) was examined by quartiles of cTTR and by cTTR as a continuous function. Centers with the highest cTTRs by quartile had lower-risk patients as reflected by lower CHADS2 scores (P<0.0001) and a lower prevalence of prior stroke or transient ischemic attack (P<0.0001). Sites with higher cTTR were predominantly from North America and Western Europe. The treatment effect of rivaroxaban versus warfarin on the primary endpoint was consistent across a wide range of cTTRs (P value for interaction=0.71). The hazard of major and non-major clinically relevant bleeding increased with cTTR (P for interaction=0.001), however, the estimated reduction by rivaroxaban compared with warfarin in the hazard of intracranial hemorrhage was preserved across a wide range of threshold cTTR values.

CONCLUSIONS

The treatment effect of rivaroxaban compared with warfarin for the prevention of stroke and systemic embolism is consistent regardless of cTTR.

Novel oral anticoagulants versus warfarin therapy at various levels of anticoagulation control in atrial fibrillation--a cost-effectiveness analysis

BACKGROUND

The decision as to whether to use more expensive novel oral anticoagulants (NOACs) or invest resources for quality improvement of warfarin therapy requires input from both clinical and economic analyses.

OBJECTIVE

Cost-effectiveness of NOACs compared to warfarin therapy at various levels of patient-time in therapeutic range (TTR) in patients with atrial fibrillation was examined, from the healthcare provider's perspective.

DESIGN, SUBJECTS AND INTERVENTION

A Markov model was used to compare life-long economic and treatment outcomes of warfarin and NOACs in a hypothetical cohort of 65-year-old atrial fibrillation patients with CHADS2 scores of 2 or above. Model inputs were derived from clinical trials published in the literature.

MAIN MEASURES

The outcome measure was incremental cost per quality-adjusted life-year (QALY) gained (ICER).

KEY RESULTS

Using United States Dollar (USD) 50,000 as the threshold of willingness-to-pay per QALY, NOACs therapy was cost-effective when TTR of warfarin therapy was 60 % or below, or monthly cost of warfarin management increased by two-fold or more to achieve 70 % TTR. Warfarin therapy was cost-effective when TTR of warfarin was 70 % with up to a 1.5-fold increment in monthly cost of care, or when TTR reached 75 % with monthly cost of warfarin care increased up to three-fold. At TTR 60 %, 70 % and 75 %, NOACs was cost-effective when monthly drug cost was < USD 200, < USD 122-185 and < USD 85-145, respectively. 10,000 Monte Carlo simulations showed NOACs to be cost-effective 83.6 %, 50.7 % and 32.7 % of the time at TTR of 60 %, 70 % and 75 %, respectively.

CONCLUSIONS

The acceptance of NOACs as cost-effective was highly dependent upon drug cost, anticoagulation control for warfarin, and anticoagulation service cost.

Racial differences in quality of life and employment outcomes in insured women with breast cancer

PURPOSE

Prior studies indicate that racial disparities are not only present in cancer survival, but also in the quality of cancer survivorship. We estimated the effect of cancer and its treatment on two measures of survivorship quality as follows: health-related quality of life and employment and hours worked for initially employed and insured women newly diagnosed with breast cancer.

METHODS

We collected employment data from 548 women from 2007 to 2011; 22 % were African-American. The outcomes were responses to the SF-36, CES-D, employment, and change in weekly hours worked from pre-diagnosis to 2 and 9 months following treatment initiation.

RESULTS

African-American women reported a 2.77 (0.94) and 1.96 (0.92) higher score on the mental component summary score at the 2 and 9 month interviews, respectively. They also report fewer depression symptoms at the 2-month interview, but were over half as likely to be employed as non-Hispanic white women (OR = 0.43; 95 % CI = 0.26 to 0.71). At the 9-month interview, African-American women had 2.33 (1.06) lower scores on the physical component summary score.

CONCLUSIONS

Differences in health-related quality of life were small and, although statistically significant, were most likely clinically insignificant between African-American and non-Hispanic white women. Differences in employment were substantial, suggesting the need for future research to identify reasons for disparities and interventions to reduce the employment effects of breast cancer and its treatment on African-American women.

IMPLICATIONS FOR CANCER SURVIVORS

African-American breast cancer survivors are more likely to stop working during the early phases of their treatment. These women and their treating physicians need to be aware of options to reduce work loss and take steps to minimize long-term employment consequences.

Postdischarge international normalized ratio testing and long-term clinical outcomes of patients with heart failure receiving warfarin: findings from the ADHERE registry linked to Medicare claims

BACKGROUND

Effective warfarin thromboprophylaxis requires maintaining anticoagulation within the recommended international normalized ratio (INR) range. INR testing rates and associations between testing and outcomes are not well understood.

HYPOTHESIS

INR testing rates after hospitalization for acute decompensated heart failure are suboptimal, and testing is associated with lower risks of mortality and adverse clinical events.

METHODS

We conducted a retrospective cohort study of patients who were long-term warfarin users and were hospitalized for heart failure, had a medical history of atrial fibrillation or valvular heart disease, and were enrolled in fee-for-service Medicare. INR testing was defined as ≥1 outpatient INR test within 45 days after discharge. Using Cox proportional hazards models, we examined associations between testing and all-cause mortality, all-cause readmission, and adverse clinical events at 1 year.

RESULTS

Among 8558 patients, 7722 (90.2%) were tested. After 1 year, tested patients had lower all-cause mortality (23.5% vs 32.6%; P < 0.001) and fewer myocardial infarctions (2.0% vs 3.3%; P = 0.02). These differences remained significant after multivariable adjustment with hazard ratios of 0.72 (95% confidence interval [CI]: 0.63-0.84; P < 0.001) and 0.58 (95% CI: 0.41-0.83; P = 0.003), respectively. Differences in all-cause readmission, thromboembolic events, ischemic stroke, and bleeding events were not statistically significant.

CONCLUSIONS

Postdischarge outpatient INR testing in patients with heart failure complicated by atrial fibrillation or valvular heart disease was high. INR testing was associated with improved survival and fewer myocardial infarctions at 1 year but was not independently associated with other adverse clinical events.

Effect of 200μG/day of vitamin K1 on the variability of anticoagulation control in patients on warfarin: a randomized controlled trial

BACKGROUND

Controversy exists whether low-dose vitamin K supplementation can improve anticoagulation control in patients with unstable anticoagulation under warfarin. In a single- centre randomized, double-blind, placebo-controlled study, we evaluated the effectiveness of 200 μg/day of vitamin K1 in patients with unstable control under warfarin.

METHODS

Effectiveness of Vitamin K1 supplementation was primarily assessed by the percentage (%) of Time-in-Therapeutic-Range (TTR) and secondarily by the standard deviation (SD) of the patient's INR values; the proportion of out-of-range INRs; and the number of dose changes on warfarin. Their change scores were obtained by subtracting the mean value in the 6 months pre-randomization from the mean value in the 6 months post-randomization. Multivariable linear-regressions identified factors associated with anticoagulation instability.

RESULTS

Fifty out of 54 patients were analyzed (intervention: n=26; placebo: n=24). Most indications (87%) for anticoagulation were venous thromboembolism (VTE). The intervention was associated with a greater reduction in the change scores for the SD of INRs between the pre and post-randomization periods compared with placebo. The mean change score was -0.259±0.307 with the intervention and -0.046±0.345 with placebo (p=0.026). There was no effect on the change scores of the (%) TTR (p=0.98), the number of INRs out-of-range (p=0.58) and the number of dose changes (p=0.604). Factors independently associated with increased variability in the SD of INRs were increased alcoholic drinks/week (p=0.017), dosing errors (p=0.0009) and missed INR appointments (p=0.035).

CONCLUSION

Vitamin K1 supplementation reduces the SD of INRs as an indicator of the variability in anticoagulation control in patients treated with warfarin for VTE.

Supervised patient self-testing of warfarin therapy using an online system

Background

Point-of-care international normalized ratio (INR) monitoring devices simplify warfarin management by allowing selected patients to monitor their own therapy in their homes. Patient self-testing (PST) has been shown to improve the clinical outcomes of warfarin therapy compared to usual care.

Objective

To compare management of warfarin therapy using PST combined with online supervision by physicians via a custom system with usual warfarin management, which involved laboratory testing and physician dosing.

Methods

Interested patients were recruited via community pharmacies to participate in a warfarin PST training program. Participants were required to have a long-term indication for warfarin, have been taking warfarin for at least 6 months, and have Internet access in their home. The training involved two sessions covering theoretical aspects of warfarin therapy, use of the CoaguChek XS, and the study website. Following training, patients monitored their INR once weekly for up to 3 months. Patients and physicians utilized a secure website to communicate INR values, dosage recommendations, and clinical incidents. Physicians provided a 6-12 month history of INR results for comparison with study results. The percentage of time spent within the therapeutic INR range (TTR) was the primary outcome, with participants acting as their own historical controls. The percentage of INR tests in range and participant satisfaction were secondary outcomes.

Results

Sixteen patients completed training requirements. The mean age of participants was 69.8 (SD 10.1) years. TTR improved significantly from 66.4% to 78.4% during PST (P=.01), and the number of tests within the target range also improved significantly (from 66.0% at prior to the study to 75.9% during PST; P=.04). Patients and physicians expressed a high degree of satisfaction with the monitoring strategy and online system.

Conclusions

PST supported by an online system for supervision was associated with improved INR control compared to usual care in a small group of elderly patients. Further research is warranted to investigate the clinical outcomes and cost-effectiveness of online systems to support patients monitoring medications and chronic conditions in the home.

Monitoring of anticoagulant therapy applying a dynamic statistical model

Patients with an increased risk of thrombosis may require treatment with vitamin K-antagonists such as warfarin. Treatment with warfarin has been reported difficult mainly due to high inter- and intraindividual variability in response to the drug [1]. Using predictive models that can predict International Normalised Ratio (INR) values enables for a higher degree of individualised warfarin dosing regime. This paper reports the outcome of the development of a dynamic prediction model. It takes warfarin intake and INR values as inputs, and uses an individual sensitivity parameter to model response to warfarin intake. The model is set on state-space form and uses Kalman filtering technique to optimise individual parameters. Retrospective test of the model proved robustness to choices of initial parameters, and feasible prediction results of both INR values and suggested warfarin dosage, which may prove beneficial for both patients and healthcare takers.

Stroke prevention in atrial fibrillation: concepts and controversies

Atrial fibrillation (AF) is the commonest cardiac rhythm disorder worldwide, affecting 1% of the general population. It is estimated that up to 16 million people in the US will suffer from the arrhythmia by 2050. AF is an independent stroke risk factor and associated with more severe strokes. For six decades, warfarin has been the only truly effective therapy to protect against stroke for patients with atrial fibrillation. Despite the proven worth of warfarin, its limitations have seen reluctance amongst physicians and patients to utilise this efficacious agent. This has meant that substantial numbers of patients are either unprotected against stroke or suboptimally protected with antiplatelet therapy.

Contemporary well-validated stroke risk factor schemes (CHA₂DS₂-VASc) now permit rapid but comprehensive evaluation of a patient’s risk for thromboembolism, allowing better identification of low-risk patients who do not require antithrombotic therapy, and whilst for those with ≥1 stroke risk factors require formal oral anticoagulation. Aspirin has been proven to be inferior to anticoagulation, and is not free of bleeding risk. We also have simple scores to easily evaluate a patient’s risk of haemorrhage (e.g. HAS-BLED).

The emergence of new oral anticoagulants should further improve stroke prevention in AF, and they successfully negotiate many of the hurdles to oral anticoagulation generated by warfarin’s limitations. Monitoring, reversal, and perioperative management are areas which require further investigation to enhance our ability to safely and effectively utilise the new agents.

Improving the management of warfarin in aged-care facilities utilising innovative technology: a proof-of-concept study

Objective

In aged-care facilities (ACFs) monitoring of warfarin can be logistically challenging and International Normalised Ratio (INR control) is often suboptimal. We aimed to determine whether an integrated information and communications technology system and the use of point-of-care (POC) monitors by nursing staff could improve the INR control of aged-care facility residents who take warfarin.

Methods

Nursing staff identified residents who were prescribed warfarin in participating ACFs. A computer program (MedePOC) was developed to store and transmit INR results from the ACFs to general practitioners (GPs) for dosage adjustment. Nursing staff received training in the use of the CoaguChek XS point-of-care INR monitor and the MedePOC software. Following a run-in phase, eligible patients were monitored weekly for up to 12 weeks. The primary outcome was the change in the time in therapeutic range (TTR) in the intervention phase compared to the TTR in the 12 months preceding the study. All GPs, nursing staff and patients were surveyed for their experiences and opinions of the project.

Key findings

Twenty-four patients and 19 GPs completed the trial across six ACFs. The mean TTR for all patients improved non-significantly from 58.9 to 60.6% (P = 0.79) and the proportion of INR tests in range improved non-significantly from 57.1 to 64.1% (P = 0.21). The mean TTR improved in 14 patients (58%) and in these patients the mean absolute improvement in TTR was 23.1%. A post hoc analysis of the INR data using modified therapeutic INR ranges to reflect the dosage adjustment practices of GPs suggested that the intervention did lead to improved INR control. The MedePOC program and POC monitoring was well received by nursing staff.

Conclusions

Weekly POC INR monitoring conducted in ACFs and electronic communication of the results and warfarin doses resulted in non-significant improvements in INR control in a small cohort of elderly residents. Further research involving modification to the communication strategy and a longer follow-up period is warranted to investigate whether this strategy can improve INR control and clinical outcomes in this vulnerable population.

Supplemental patient education for patients taking oral anticoagulants: systematic review and meta-analysis

OBJECTIVE

Lack of patient knowledge has been associated with poor anticoagulation control, but the effect of patient education on clinical outcomes is unclear. We systematically reviewed the effect of supplemental patient education vs. usual care on hemorrhage, thromboembolic events (TEEs), time in therapeutic range (TTR) and knowledge test scores for all oral anticoagulants.

DATA SOURCES

The data sources were electronic databases, including MEDLINE, EMBASE, CENTRAL, CINAHL and IPA, to February 2012 examining any oral anticoagulant. We reviewed references for additional potentially relevant studies.

METHODS

Only randomized controlled trials (RCTs) were considered. Data extraction and quality assessment were conducted with GRADE. Pooled relative risks (RRs) were calculated, and heterogeneity was determined by use of χ(2) and I(2) statistics.

RESULTS

Seven RCTs (n = 1209) were included in the systematic review, and five RCTs (n = 847) in the meta-analysis. All included studies examined vitamin K antagonists. No significant difference was found for hemorrhage (RR 0.92, 95% confidence interval [CI] 0.04-20.56), TEE (RR 0.66, 95% CI 0.10-4.39), a composite outcome of hemorrhage or TEE (RR 0.48, 95% CI 0.23-1.01), or TTR (mean absolute difference of 2.02%, 95% CI - 2.81 to 6.84). Evidence was conflicting on the impact of supplemental education on test scores. All trials had at least one substantial methodologic limitation.

CONCLUSION

Current evidence does not support supplemental patient education as a means to improve patient outcomes, but the quality of this evidence is poor. Larger randomized trials are needed with longer follow-up, recruitment of patients initiating anticoagulation in primary care settings, and clearly defined education interventions.

Anticoagulation early after mechanical valve replacement: improved management with patient self-testing

OBJECTIVE

Self-testing to determine the international normalized ratio improves management with warfarin and reduces the risks of adverse events. Self-testing usually begins several weeks after hospital dismissal after valve replacement. We aimed to compare the in-hospital initiation of international normalized ratio self-testing with usual care in mechanical heart valve recipients.

METHODS

A total of 200 adult mechanical heart valve recipients were randomly assigned to in-hospital international normalized ratio self-testing instruction or usual care. Instruction for self-testing patients began on the fourth postoperative day. The patients were followed up for 3 months to compare the number of international normalized ratio tests, percentage of time in the therapeutic range, and adverse events.

RESULTS

The baseline characteristics were similar between the 2 groups. During the first 3 postoperative months, the usual-care group underwent an average of 10 international normalized ratio tests, and the self-testing group completed 14 international normalized ratio tests. The mean ± SD percentage of international normalized ratio tests within the therapeutic range was 45% ± 22% for the usual-care group and 52% ± 22% for the self-testing group (P = .05). Within 90 days after dismissal, transient ischemic attack occurred in 1 patient in the usual-care group and 2 patients in the self-testing group. Bleeding complications occurred in 3 patients in the usual-care group and 5 patients in the self-testing group.

CONCLUSIONS

Management of anticoagulation with warfarin after mechanical valve replacement is improved with self-testing, even during the early postoperative phase when international normalized ratio testing is performed frequently. Although the incidence of adverse events was similar in the 2 groups, better control of the international normalized ratio would be expected to improve outcome in large populations of patients.

Stroke Prevention in Atrial Fibrillation: Where are We Now?

Atrial fibrillation is the commonest arrhythmia worldwide and is a growing problem. AF is responsible for 25% of all strokes, and these patients suffer greater mortality and disability. Warfarin has traditionally been the only successful therapy for stroke prevention, but its limitations have resulted in underutilisation. Major progress has been made in AF research, leading to improved management strategies. Better risk stratification permits identification of truly low-risk patients who do not require anticoagulation and we are able to simplify ourevaluation of a patient's bleeding risk.The advent of novel anticoagulants means warfarin is no longer the only choice for stroke prophylaxis. These drugs circumvent many of warfarin's inconveniences, but onlylong-term study and use will conclusively demonstrate how they compare to warfarin. The landscape of stroke prevention in AF has changed with effective alternatives to warfarin available for the first time in 60 years-but each new option brings new considerations.