Home INR Monitoring Clinical Outcomes

Improving outcomes for patients on warfarin includes improving patient safety, the quality of warfarin management, and time in target range.

High Quality Warfarin Management

Defining the quality needed to manage warfarin to maintain an efficacy and safety advantage over new oral anticoagulants is an area of great interest to clinicians, patients and payers. Recently, the international peer-review journal Expert Opinion on Emerging Drugs evaluated dabigatran, rivaroxaban, and apixaban and determined that warfarin controlled at 65.5% or higher yielded no clinical benefit of switching patients off warfarin. The advantage of new agents over warfarin is the reduced incidence of intracranial hemorrhage (ICH). Studies demonstrating a reduced ICH rate did not find this advantage when warfarin was well controlled.1, 2, 3

An additional element of risk includes the traditional poor adherence to chronic medications that do not require routine monitoring. With warfarin, adherence is validated with each INR test result reassuring the prescribing physician that patients are taking their medication as directed. Using our program clinicians have the benefit of adjusting medication as needed while optimizing management to save time and optimize workflow.4 The Management by Exception principle can be applied to improve clinic efficiencies of Home INR Monitoring patients. Protocols result in significant clinical benefits for the patient and improve operational efficiency for healthcare providers.

The STABLE demonstrated high quality warfarin management in a real-world population of over 29,500 patients for two and a half years and sustained the high quality of warfarin control.5


Warfarin Therapy Control, by Duration of PST

Three independent investigators1,2,3  have set the quality of warfarin control from 65.5% to 73% or higher in order for warfarin to be a safer and more efficacious choice for patients than the new agents. The STABLE study found weekly self-testing exceeded all published levels of warfarin control needed to switch patients to a new agent. Self-testing remains a covered service under Medicare and most private insurance plans for indications including atrial fibrillation, DVT/PE, and mechanical heart valve replacement patients.Prescribing warfarin with an Alere Home INR Monitoring program is the superior choice for anticoagulation management.


Patient Safety

Patient safety in oral anticoagulation is not limited to reducing or eliminating the risk of bleeding; it includes the prevention of blood clots that often lead to a stroke, heart attack or pulmonary embolism. Adherence to medication and regularly testing INR is critical to patient safety. Alere provides an adherence program for all patients participating in our Home INR Monitoring program. It is one component to improving patient safety.

When patients adhere to their doctor’s instructions, improved clinical outcomes result.

Safety for patients taking warfarin is associated with keeping patients in or very close to their therapeutic target range. Alere takes pride in providing a 74% time in therapeutic range for their weekly patient self-testing population.1

Time in Therapeutic Range (TTR)

Time in therapeutic range (TTR) is a key measurement of patient safety; however  as a sole measure of warfarin patient safety. A patient with an 85% TTR may be at far greater risk than a patient with a TTR of 60%, here’s why it can be limiting:


Patient (100 tests)


% Critical Value

INR’s 1.8 – 3.9



15% (15 tests)

0 tests



3% (3 tests)

37 tests


While Bob appeared to be the safer patient using only TTR as a surrogate measure, his missed INR test results swung to critical value increasing his risk for stroke and bleeding (3.5 fold, 6 fold than if he were in or close to his therapeutic range).1,2 Mary, on the other hand, appeared less controlled by TTR but her out-of-range test results were close to her therapeutic range, resulting in very little if any risk of adverse events.


46% reduction

A 29,529 patient real-world study found weekly patient self-testing experienced a 49% reduction in the incidence of critical value* INR tests over self-testing patients who tested with more than 7 days between tests.3

 *Critical value: < 1.5 or > 5.0


Time in therapeutic range is limited in its role of evaluating warfarin patient safety. Determining the frequency of extreme values is a more reliable predictor of short and long term patient and practice risk.

Outcome Improvements

Improving warfarin outcomes includes improving the quality of warfarin management. Over the last 10 years, outcomes for warfarin have improved dramatically. Clinical trials from 2003-2011 have included time in therapeutic range significantly higher than in trials between 1989-1993, resulting in a reduction in stroke rates from 2.09% to 1.66% per year. The improvement in clinical outcomes represents a 20% reduction in stroke within the last ten years vs. the prior ten years.1

Contributing to the improvement in clinical outcomes includes the increased use of patient self-testing. The approval and reimbursement of patient self-testing began in 2002 and expanded to include atrial fibrillation and DVT/PE in 20082. In 2015, ICD-10 expanded the codes to include the location in body. Medicare has allowed over 140 codes for INR monitoring. Time in therapeutic range for weekly self-testing has been shown to a achieve 74% in a real-world evaluation.3


Benefits of Home INR Monitoring

Self-testing is a clinical tool that allows doctors and nurses to optimize patient anticoagulation management. Medicare has established a reimbursement code to support a testing frequency ‘up to and including weekly testing’ to meet the pharmacology and pharmacokinetics need of warfarin monitoring.1

Medicare’s reimbursement for up to and including weekly was the result of reviewing 20 independent clinical trials spanning over 30 years of international and U.S. based studies.

Weekly testing empowers patients, removes worry between office visits, and improves patient safety. “The probability that an individual's average INR will be out of range decreases as the number of tests increases. Therefore, the proportion of patients with average INRs out of range may decrease as number of tests increases. All things being equal, increased frequency of testing should lead to a more accurate assessment of TTR.”1


Defining and Reducing Warfarin Risk

There is risk for both patients taking warfarin and practices managing warfarin patients. Incidence of critical value INR results time in therapeutic range (TTR) and are both important factors in risk reduction with critical value results of less than 1.5 or greater than 5.0. Patients are 3.5 times the risk for thrombosis1 over an in-range result whereas an INR of 5.0 increases a bleeding risk 6 times that of a test result in range.2

Our home INR monitoring program supports compliance and encourages regular testing.  “More frequent testing also provides the ability to detect any drift in INR stability sooner, rather than later, thus keeping INR within a set range.”3

The largest single study of real-world patients self-testing found a dramatic 49% reduction in critical value risk in patients that tested weekly, this benefit was sustained for the two and half year study period.


Results - Critical Value Reduction

Home INR Monitoring supports patients between regularly scheduled office visits.

Adherence and compliance with Home INR Monitoring for your patients provides the potential for you to realize the full benefits of anticoagulation with warfarin, as seen in clinical trials.

The Self-Testing Analysis Based on Long-Term Experience (STABLE) study1, the largest study ever conducted, found that weekly patient self-testing provided the greatest safety for patients taking warfarin:

• Weekly home testing demonstrated a 46% reduction in risk of major bleeding event or stroke.

• Weekly testing provided optimal control at 74% time in target range (TTR).

• Surpassed previous benchmark controlled trials TTR by 8% (THINRS3, Bloomfield 22-study meta-analysis4).

Patient INR self-testing is clinically proven to increase time in therapeutic. Testing INR weekly results in fewer INR amplitudes, which are commonly associated with adverse events.1, 2

Patients testing with Alere Home INR Monitoring are compliant over 63% of the time to their testing frequency.5 There is a higher rate of nonadherence with both dabigatran or rivaroxaban with 1 in 4 patients discontinuing dabigatran, and 1 in 3 patients discontinuing rivaroxaban within 6 months of initiation.6

Percent Time in Target Range by Testing Frequency

CMS Decision and Coverage

Medicare has recognized the importance of the weekly testing for patient safety and they provide coverage within the following guidelines7:

Provision of test materials and equipment for home INR Monitoring of patient with either mechanical heart valve(s), chronic atrial fibrillation, or venous thromboembolism who meets Medicare coverage criteria; includes: provision of materials for use in the home and reporting of test results to physician; testing not occurring more frequently than once a week; testing materials, billing units of service include 4 tests.

Clinically Relevant Results

Alere provides clinically relevant data to manage your patients.

Test results are stored in our secure database management system and help you manage your patients and workflows to optimize your anticoagulation management.

Choose the way you prefer to receive results.

  • Fax all patient test results on the schedule you choose
  • Alert you only when a patient is out-of-range (Management by Exception)
  • Access patient results electronically

Utilize summary reports to track patient outcomes by compliance and TTR.

Manage your anticoagulation patients at your fingertips.

The web-based Alere CoagClinic® decision support application allows you to keep track of INR results, dosing and more – anytime, anywhere.

Call us at 1.866.408.1205 to talk to an associate today!