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

Clinical service organisation for adults with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is an increasingly prevalent heart rhythm condition in adults. It is considered a common cardiovascular condition with complex clinical management. The increasing prevalence and complexity in management underpin the need to adapt and innovate in the delivery of care for people living with AF. There is a need to systematically examine the optimal way in which clinical services are organised to deliver evidence-based care for people with AF. Recommended approaches include collaborative, organised multidisciplinary, and virtual (or eHealth/mHealth) models of care.

OBJECTIVES

To assess the effects of clinical service organisation for AF versus usual care for people with all types of AF.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and CINAHL to October 2022. We also searched ClinicalTrials.gov and the WHO ICTRP to April 2023. We applied no restrictions on date, publication status, or language.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), published as full texts and as abstract only, involving adults (≥ 18 years) with a diagnosis of any type of AF. We included RCTs comparing organised clinical service, disease-specific management interventions (including e-health models of care) for people with AF that were multicomponent and multidisciplinary in nature to usual care.

DATA COLLECTION AND ANALYSIS

Three review authors independently selected studies, assessed risk of bias, and extracted data from the included studies. We calculated risk ratio (RR) for dichotomous data and mean difference (MD) or standardised mean difference (SMD) for continuous data with 95% confidence intervals (CIs) using random-effects analyses. We then calculated the number needed to treat for an additional beneficial outcome (NNTB) using the RR. We performed sensitivity analyses by only including studies with a low risk of selection and attrition bias. We assessed heterogeneity using the I² statistic and the certainty of the evidence according to GRADE. The primary outcomes were all-cause mortality and all-cause hospitalisation. The secondary outcomes were cardiovascular mortality, cardiovascular hospitalisation, AF-related emergency department visits, thromboembolic complications, minor cerebrovascular bleeding events, major cerebrovascular bleeding events, all bleeding events, AF-related quality of life, AF symptom burden, cost of intervention, and length of hospital stay.

MAIN RESULTS

We included 8 studies (8205 participants) of collaborative, multidisciplinary care, or virtual care for people with AF. The average age of participants ranged from 60 to 73 years. The studies were conducted in China, the Netherlands, and Australia. The included studies involved either a nurse-led multidisciplinary approach (n = 4) or management using mHealth (n = 2) compared to usual care. Only six out of the eight included studies could be included in the meta-analysis (for all-cause mortality and all-cause hospitalisation, cardiovascular mortality, cardiovascular hospitalisation, thromboembolic complications, and major bleeding), as quality of life was not assessed using a validated outcome measure specific for AF. We assessed the overall risk of bias as high, as all studies had at least one domain at unclear or high risk of bias rating for performance bias (blinding) in particular. Organised AF clinical services probably result in a large reduction in all-cause mortality (RR 0.64, 95% CI 0.46 to 0.89; 5 studies, 4664 participants; moderate certainty evidence; 6-year NNTB 37) compared to usual care. However, organised AF clinical services probably make little to no difference to all-cause hospitalisation (RR 0.94, 95% CI 0.88 to 1.02; 2 studies, 1340 participants; moderate certainty evidence; 2-year NNTB 101) and may not reduce cardiovascular mortality (RR 0.64, 95% CI 0.35 to 1.19; 5 studies, 4564 participants; low certainty evidence; 6-year NNTB 86) compared to usual care. Organised AF clinical services reduce cardiovascular hospitalisation (RR 0.83, 95% CI 0.71 to 0.96; 3 studies, 3641 participants; high certainty evidence; 6-year NNTB 28) compared to usual care. Organised AF clinical services may have little to no effect on thromboembolic complications such as stroke (RR 1.14, 95% CI 0.74 to 1.77; 5 studies, 4653 participants; low certainty evidence; 6-year NNTB 588) and major cerebrovascular bleeding events (RR 1.25, 95% CI 0.79 to 1.97; 3 studies, 2964 participants; low certainty evidence; 6-year NNTB 556). None of the studies reported minor cerebrovascular events.

AUTHORS' CONCLUSIONS

Moderate certainty evidence shows that organisation of clinical services for AF likely results in a large reduction in all-cause mortality, but probably makes little to no difference to all-cause hospitalisation compared to usual care. Organised AF clinical services may not reduce cardiovascular mortality, but do reduce cardiovascular hospitalisation compared to usual care. However, organised AF clinical services may make little to no difference to thromboembolic complications and major cerebrovascular events. None of the studies reported minor cerebrovascular events. Due to the limited number of studies, more research is required to compare different models of care organisation, including utilisation of mHealth. Appropriately powered trials are needed to confirm these findings and robustly examine the effect on inconclusive outcomes. The findings of this review underscore the importance of the co-ordination of care underpinned by collaborative multidisciplinary approaches and augmented by virtual care.

Readmission After Bioprosthetic vs Mechanical Mitral Valve Replacement in the United States

BACKGROUND

Choosing between a bioprosthetic and a mechanical mitral valve is an important decision for both patients and surgeons. We compared patient outcomes and readmission rates after bioprosthetic mitral valve replacement (Bio-MVR) vs mechanical mitral valve replacement (Mech-MVR).

METHODS

The Nationwide Readmissions Database was queried to identify 31 474 patients who underwent isolated MVR (22 998 Bio-MVR, 8476 Mech-MVR) between January 1, 2016, and December 31, 2018. Propensity score matching by age, sex, elective status, and comorbidities was used to compare outcomes between matched cohorts by prosthesis type. Freedom from readmission within the first calendar year was estimated by Kaplan-Meier analysis and compared between matched cohorts.

RESULTS

Bio-MVR patients were older (median age, 69 vs 57 years; P < .001) and had more comorbidities (median Elixhauser score, 14 vs 11; P < .001) compared with Mech-MVR patients. After propensity score matching (n = 15 549), Bio-MVR patients had similar operative mortality (3.5% vs 3.4%; P = .97) and costs ($50 958 vs $49 782; P = .16) but shorter lengths of stay (8 vs 9 days; P < .001) and fewer 30-day (16.0% vs 18.1%; P = .04) and 90-day (23.8% vs 26.8%; P = .01) readmissions compared with Mech-MVR patients. The difference in readmissions persisted at 1 year (P = .045). Readmission for bleeding or coagulopathy complications was less common with Bio-MVR (5.7% vs 10.1%; P < .001).

CONCLUSIONS

Readmission was more common after Mech-MVR than after Bio-MVR. Identifying and closely observing patients at high risk for bleeding complications may bridge the readmissions gap between Bio-MVR and Mech-MVR.

Primary Anti-Phospholipid Antibody Syndrome: Real-World Defining Features of Rethrombosis in the Course of Disease

Objective

We aimed to identify features that allow differentiation of primary antiphospholipid syndrome (PAPS) patients that suffer recurrent thrombotic events (RTE) despite anticoagulation, from the other diagnosed PAPS patients.

Methods

This was an exploratory study of anticoagulated PAPS patients attending an Autoimmune Diseases Unit (1998-2018). From 2016, anti-phospholipid antibodies and lupus anticoagulant were determined for each patient at consecutive visits, collected together with retrospective clinical characteristics, laboratory, and therapeutic markers and compared according to the occurrence of thrombotic events during follow-up.

Results

Overall, two thirds of the patients were female, 93% were Caucasian, with a median age of 40 years at diagnosis, for a median time of 11.5 years in follow-up. Out of 54 patients, 10 were identified with RTE. There were no significant differences among the RTE and non-RTE patients as far as classical risk factors for clotting disorders. The RTE group was characterized by a higher proportion of younger patients, male sex and positivity for all laboratory markers, and initially and over follow-up as well as a sustained high-risk profile based on APS laboratory markers. Anticardiolipin IgG at onset was the only statistically significant marker of the RTE group. At the end of follow-up, consistent reversion to negative status was a rare event, observed in 20% of RTE vs. 25% of non-RTE patients.

Conclusions

Despite therapy, we were able to identify features associated to thrombotic events in patients with PAPS. Prospectively regular clinical and laboratory monitoring might be warranted in order to treat APS more assertively.

Improved Time in Therapeutic Range with International Normalized Ratio Remote Monitoring for Patients with Left Ventricular Assist Devices

Despite advances in therapy, bleeding and thromboembolic events are frequent complications in patients with left ventricular assist device (LVAD) support. Maintaining warfarin in therapeutic range has been shown to be more challenging in this patient population compared to other indications. Patients with LVADs on warfarin typically are within goal international normalized ratio (INR) range 36-57% of the time, compared to about 65% for other indications. The goal of this study was to evaluate if an INR remote monitoring system along with the implementation of a standardized warfarin management protocol improves warfarin time in therapeutic range (TTR) for patients with LVADs. This single-center, retrospective, observational study included 78 patients with LVADs that were followed at our academic center from January 2015 to October 2017. In October 2016, we updated our warfarin management protocol and implemented a remote monitoring system with patients' weekly INR results monitored. The primary objective of the study was to determine the difference between TTRs in remote monitoring versus standard monitoring. We found that the average TTR was significantly higher in the remote monitoring group compared to the standard monitoring cohort (61.1% vs. 40.0%, p < 0.005). However, bleeding, thrombotic incidence, and hospital readmission rates were similar between the two patient cohorts. Remote monitoring improved warfarin TTR significantly in this study and may have the potential to improve anticoagulation-related outcomes in patients with LVADs.

Performance of the microINR Point-of-Care System Used by Self-Testing Patients: A Multicenter Clinical Trial

Introduction  Anticoagulation monitoring is a major practical and clinical challenge. We assessed the performance of the microINR system in patient self-testing (PST). Methods  This study was performed at four US medical centers. After the training visit of warfarin anticoagulated patients ( n  = 117) on microINR system, PST was performed at home and in two visits to the medical centers. At the medical centers, both PST and healthcare professionals (HCPs) performed duplicate tests with the microINR System. A venous blood sample for the laboratory testing was also extracted. Accuracy and precision were assessed. Results  The comparison between microINR PST results and microINR HCP results revealed an equivalence with a slope of 1.00 (95% confidence interval [CI]: 1.00-1.00), and an intercept of 0.00 (95% CI: 0.00-0.00). When compared with the laboratory analyzer, microINR PST results also showed good correlation with a slope of 0.94 (95% CI: 0.86-1.04) and an intercept of 0.14 (95% CI: -0.09-0.34). Predicted bias values at international normalized ratio (INR) 2.0, 3.5, and 4.5 were 0% against HCP and ≤2.5% against the laboratory. Analytical agreement with both HCP and laboratory was 100% according to ISO17593 and 99.1 and 100% according to CLSI POCT14 with HCP and laboratory, respectively. Clinical agreement with HCP regarding 2.0-4.0 as INR therapeutic range was 98% (within range). The precision (coefficient of variation) of microINR system used by PST was comparable to HCP. Conclusion  The microINR results when used by self-testing patients show satisfactory concordance to both HCP results and laboratory analyzer. The microINR system is adequate for self-testing use.

Updates in Anticoagulation Therapy Monitoring

In the past six decades, heparin and warfarin were the primary anticoagulants prescribed for treatment and prophylaxis of venous thromboembolism worldwide. This has been accompanied by extensive clinical knowledge regarding dosing, monitoring, and reversal of these anticoagulants, and the resources required to do so have largely been readily available at small and large centers alike. However, with the advent of newer oral and parenteral anticoagulants such as low molecular weight heparins, factor Xa inhibitors, and direct thrombin inhibitors in recent years, new corresponding practice guidelines have also emerged. A notable shift in the need for monitoring and reversal agents has evolved as well. While this has perhaps streamlined the process for physicians and is often desirable for patients, it has also left a knowledge and resource gap in clinical scenarios for which urgent reversal and monitoring is necessary. An overview of the currently available anticoagulants with a focus on the guidelines and available tests for anticoagulant monitoring will be discussed in this article.

In-home Compared With In-Clinic Warfarin Therapy Monitoring in Mechanical Heart Valves: A Population-Based Study

Objective

To evaluate differences in time in therapeutic range (TTR), major bleeding, thromboembolism, and survival comparing in-home and in-clinic international normalized ratio monitoring for patients with mechanical heart valves receiving warfarin anticoagulation.

Patients and Methods

An observational population-based study of 383 patients (mean ± SD age, 61.5±14.1 years; 38.6% female) with mechanical heart valves (aortic, 77.8%; mitral, 31.1%; tricuspid, 1%; pulmonic 0.2%; and multiple, 9.7%) was performed from January 1, 2012, through December 31, 2017. The target international normalized ratio was 2.5 for 199 patients (52.0%) and 3.0 for 184 (48.0). Of these patients, 37.9% (n=145) were managed by in-home monitoring (cases) and 62.1% (n=238) were monitored in the clinic (controls).

Results

During median follow-up of 3.1 years, mean ± SD TTR was similar between in-home (66.6%±19.2%) and in-clinic (67.2%±19.8%) monitoring (P=.76). There were no differences between the in-home and in-clinic groups regarding survival to major bleeding (5.7% per person-year vs 6.7% per person-year; P=.66) or thrombotic complications (2.3% vs 1.8%; P=.56). In-home monitoring was associated with reduced all-cause mortality (hazard ratio, 0.40; 95% CI, 0.19 to 0.83; P=.01) on univariate analysis; however, this was no longer apparent when controlling for age and baseline left ventricular ejection fraction.

Conclusion

In this real-world population-based study of patients with mechanical heart valves, in-home monitoring was equivalent to in-clinic monitoring regarding TTR and important clinical outcomes.

American Society of Hematology 2018 guidelines for management of venous thromboembolism: optimal management of anticoagulation therapy

BACKGROUND

Clinicians confront numerous practical issues in optimizing the use of anticoagulants to treat venous thromboembolism (VTE).

OBJECTIVE

These evidence-based guidelines of the American Society of Hematology (ASH) are intended to support patients, clinicians and other health care professionals in their decisions about the use of anticoagulants in the management of VTE. These guidelines assume the choice of anticoagulant has already been made.

METHODS

ASH formed a multidisciplinary guideline panel balanced to minimize potential bias from conflicts of interest. The McMaster University GRADE Centre supported the guideline development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to assess evidence and make recommendations, which were subject to public comment.

RESULTS

The panel agreed on 25 recommendations and 2 good practice statements to optimize management of patients receiving anticoagulants.

CONCLUSIONS

Strong recommendations included using patient self-management of international normalized ratio (INR) with home point-of-care INR monitoring for vitamin K antagonist therapy and against using periprocedural low-molecular-weight heparin (LMWH) bridging therapy. Conditional recommendations included basing treatment dosing of LMWH on actual body weight, not using anti-factor Xa monitoring to guide LMWH dosing, using specialized anticoagulation management services, and resuming anticoagulation after episodes of life-threatening bleeding.

Point-of-care coagulation monitoring: first clinical experience using a paper-based lateral flow diagnostic device

Vitamin K antagonists such as warfarin are the most widely used class of oral anticoagulants. Due to a narrow therapeutic window, patients on warfarin require regular monitoring. Self-testing using point-of-care (POC) diagnostic devices is available, but cost makes this monitoring method beyond reach for many. The main objective of this research was to assess the clinical utility of a low-cost, paper-based lateral flow POC diagnostic device developed for anticoagulation monitoring without the need for a separate electronic reader. Custom-fabricated lateral flow assay (LFA) test strips comprised of a glass fiber sample pad, a nitrocellulose analytical membrane, a cellulose wicking pad, and a plastic backing card were assembled in a plastic cassette. Healthy volunteers and patients on warfarin therapy were recruited for this prospective study. For each participant, a whole blood sample was collected via fingerstick to determine: (1) international normalized ratio (INR) using the CoaguChek® XS coagulometer, (2) hematocrit by centrifugation, and (3) red blood cell (RBC) travel distance on the experimental LFA device after 240 s using digital image analysis. RBC travel distance measured on the LFA device using blood samples obtained from warfarin patients positively correlated with increasing INR value and the LFA device had the capability to statistically distinguish between healthy volunteer INR values and those for patients groups with INR ≥ 2.6. From these data, it is predicted that this low-cost, paper-based LFA device can have clinical utility for identifying anticoagulated patients taking vitamin K antagonists who are outside of the desired therapeutic efficacy window.