Patient Self-testing Research Articles

Meta-analysis: Effect of Patient Self-testing and Self-management of Long-Term Anticoagulation on Major Clinical Outcomes

Anticoagulation with vitamin K antagonists reduces major thromboembolic complications in at-risk patients. With portable monitoring devices, patients can conduct their own international normalized ratio testing and dose adjustment at home. To determine whether patient self-testing (PST), alone or in combination with self-adjustment of doses (patient self-management [PSM]), is associated with a reduction in thromboembolic complications and all-cause mortality without an increase in major bleeding events compared with usual care. MEDLINE and the Cochrane Central Register of Controlled Trials. Studies published in English from 1966 to October 2010 that enrolled outpatient adults receiving long-term (>3 months) oral anticoagulant therapy and that compared PST or PSM with care in a physician's office or an anticoagulation clinic were included. Two investigators reviewed each article. Three investigators extracted data from articles that met inclusion criteria by using standardized data abstraction forms. Studies were assessed for quality, and the overall strength of evidence was rated for each clinical outcome. Twenty-two trials, with a total of 8413 patients, were included. In one half of the trials, fewer than 50% of potentially eligible persons successfully completed the training and agreed to be randomly assigned. Patients randomly assigned to PST or PSM had lower total mortality (Peto odds ratio [OR], 0.74 [95% CI, 0.63 to 0.87]), lower risk for major thromboembolism (Peto OR, 0.58 [CI, 0.45 to 0.75]), and no increased risk for a major bleeding event (Peto OR, 0.89 [CI, 0.75 to 1.05]). The strength of evidence was moderate for the bleeding and thromboembolism outcomes but low for mortality. Eight of 11 trials reported that patient satisfaction, quality of life, or both was better with PST or PSM than with usual care. In one half of the trials, fewer than 50% of the potentially eligible patients were randomly assigned. Only 5 trials were considered high quality, and only 2 were conducted in the United States. No studies addressed whether PST or PSM is safe during the high-risk initiation phase. Compared with usual care, PST with or without PSM is associated with significantly fewer deaths and thromboembolic events, without increased risk for a serious bleeding event, for a highly selected group of motivated adult patients requiring long-term anticoagulation with vitamin K antagonists. Whether this care model is cost-effective and can be implemented successfully in typical U.S. health care settings requires further study. U.S. Department of Veterans Affairs Health Services Research and Development Service.

Self-testing and self-management of oral anticoagulation therapy in children

Children and adolescents on oral anticoagulation therapy (OAT) present special challenges in terms of rapid fluctuations in International Normalised Ratio (INR) values, interruption in daily life due to frequent hospital/doctor visits, and difficulties and pain in the performance of venepuncture. Optimised management of OAT improves the quality of treatment, potentially accomplished by new methods such as patient self-testing (PST) and patient self-management (PSM). A review was performed, identifying 11 trials with children and adolescents. All studies had different methodological problems, predominantly by being non-randomised trials. A total of 284 patients were included with a mean follow-up of 22 months, finding a time within therapeutic INR target range between 63% and 84%. The coagulometers used for estimating the INR values were found to have sufficient precision and accuracy for clinical use, but external quality control is probably advisable. It can be concluded that PST and PSM are at least as good treatment options as conventional management in highly selected children. Larger studies, preferably randomised, controlled trials using clinical endpoints, are obviously needed in order to elucidate whether these new regimens of treatment are superior to conventional management of oral anticoagulation therapy.

The ‘carry-over’ effects of patient self-testing: Positive effects on usual care management by an anticoagulation management service

Introduction Patient self-testing (PST) of the international normalised ratio (INR) has a positive effect on anticoagulation control. This study investigated whether the benefits of PST (other than increased frequency of testing, e.g. patient education, empowerment, compliance etc.) could be ‘carried-over’ into usual care management after a period of home-testing has ceased. Material and methods Patients that completed a six month period of PST (as part of a randomised controlled trial) but returned to clinic management when the trial ended were included in the study. The primary outcome variable was the difference in anticoagulation control (measured using the time in therapeutic range) between the two periods. A group of patients who were managed solely by the anticoagulation clinic served as the control. Results There was no significant difference in median time in therapeutic range (TTR) between the 52 patients during clinic management post-PST and the six month period of PST (75% vs 75.3%; p = 0.061). Patients tested more frequently while home-testing compared with the subsequent six month period of clinic management (once every 5.6 ± 0.7 days compared with once every 23.2 ± 7.4 days; p = 0.000). Patients with previous experience of PST performed significantly better than the control group of patients (n = 107) that were managed solely by the anticoagulation clinic (75% vs 59.7%; p = 0.009) despite less frequent monitoring of the INR (every 23.2 ± 7.4 days vs. 17.4 ± 6.7 days; p = 0.000). Conclusions The improvements in anticoagulation control observed during a period of PST can be sustained when patients cease home-testing and revert back to usual care management.

An evaluation of patient self-testing competency of prothrombin time for managing anticoagulation: pre-randomization results of VA Cooperative Study #481–The Home INR Study (THINRS)

Prior studies suggest patient self-testing (PST) of prothrombin time (PT) can improve the quality of anticoagulation (AC) and reduce complications (e.g., bleeding and thromboembolic events). "The Home INR Study" (THINRS) compared AC management with frequent PST using a home monitoring device to high-quality AC management (HQACM) with clinic-based monitoring on major health outcomes. A key clinical and policy question is whether and which patients can successfully use such devices. We report the results of Part 1 of THINRS in which patients and caregivers were evaluated for their ability to perform PST. Study-eligible patients (n = 3643) were trained to use the home monitoring device and evaluated after 2-4 weeks for PST competency. Information about demographics, medical history, warfarin use, medications, plus measures of numeracy, literacy, cognition, dexterity, and satisfaction with AC were collected. Approximately 80% (2931 of 3643) of patients trained on PST demonstrated competency; of these, 8% (238) required caregiver assistance. Testers who were not competent to perform PST had higher numbers of practice attempts, higher cuvette wastage, and were less able to perform a fingerstick or obtain blood for the cuvette in a timely fashion. Factors associated with failure to pass PST training included increased age, previous stroke history, poor cognition, and poor manual dexterity. A majority of patients were able to perform PST. Successful home monitoring of PT with a PST device required adequate levels of cognition and manual dexterity. Training a caregiver modestly increased the proportion of patients who can perform PST.

The reliability of point‐of‐care prothrombin time testing. A comparison of CoaguChek S® and XS® INR measurements with hospital laboratory monitoring

The development of point-of-care (POC) testing devices enables patients to test their own international normalized ratio (INR) at home. However, previous studies have shown that when compared with clinical laboratory values, statistically significant differences may occur between the two methods of INR measurement. The aim of this study was to evaluate the accuracy of the CoaguChek S and XS POC meters relative to clinical laboratory measurements. As part of a randomized, crossover patient self-testing (PST) study at Cork University Hospital, patients were randomized to 6 months PST or 6 months routine care by the anticoagulation management service. During the PST arm of the study, patients measured their INR at home using the CoaguChek S or XS POC meter. External quality control was performed at enrollment, 2 months and 4 months by comparing the POC measured INR with the laboratory determined value. One hundred and fifty-one patients provided 673 paired samples. Good correlation was shown between the two methods of determination (r = 0.91), however, statistically significant differences did occur. A Bland-Altman plot illustrated good agreement of INR values between 2.0 and 3.5 INR units but there was increasing disagreement as the INR rose above 3.5. Eighty-seven per cent of all dual measurements were within the recommended 0.5 INR units of each other. This study adds to the growing evidence that POC testing is a reliable and safe alternative to hospital laboratory monitoring but highlights the importance of external quality control when these devices are used for monitoring oral anticoagulation.

Randomized controlled trial of supervised patient self-testing of warfarin therapy using an internet-based expert system.

Increased frequency of prothrombin time testing, facilitated by patient self-testing (PST) of the International Normalized Ratio (INR) can improve the clinical outcomes of oral anticoagulation therapy (OAT). However, oversight of this type of management is often difficult and time-consuming for healthcare professionals. This study reports the first randomized controlled trial of an automated direct-to-patient expert system, enabling remote and effective management of patients on OAT. A prospective, randomized controlled cross-over study was performed to test the hypothesis that supervised PST using an internet-based, direct-to-patient expert system could provide improved anticoagulation control as compared with that provided by an anticoagulation management service (AMS). During the 6 months of supervised PST, patients measured their INR at home using a portable meter and entered this result, along with other information, onto the internet web page. Patients received instant feedback from the system as to what dose to take and when the next test was due. During the routine care arm, patients attended the AMS at least every 4-6 weeks and were dosed by the anticoagulation pharmacist or physician. The primary outcome variable was the difference in the time in therapeutic range (TTR) between both arms. One hundred and sixty-two patients were enrolled (male 61.6%, mean age 58.7 years), and 132 patients (81.5%) completed both arms. TTR was significantly higher during PST management than during AMS management (median TTR 74% vs 58.6%; z=5.67, P < 0.001). The use of an internet-based, direct-to-patient expert system for the management of PST improves the control of OAT as compared with AMS management.

Randomized Controlled Trial of Supervised Patient Self-Testing of Warfarin Therapy Using An Internet Based Expert System

Improved anticoagulation control results in improved outcomes, with a decrease in the incidence of bleeding and thromboembolic events. The outcomes of oral anticoagulation therapy (OAT) are dependent on the model of care used to manage warfarin therapy, with better outcomes associated with the use of a specialised anticoagulation management service (AMS), computerized decision support and increased testing frequency (facilitated by patient self-testing (PST) of the international normalised ratio (INR)) (Ansell and Hughes 1996). This study uses a novel strategy to combine the advantages of these three approaches to warfarin management. A prospective, randomized controlled cross-over study was carried out at the anticoagulation clinic of Cork University Hospital, Ireland, to test the hypothesis that supervised PST using an internet based expert system could provide comparable anticoagulation control to that provided by traditional outpatient AMS management. This was a cross-over study; patients served in both AMS and supervised PST arms, with random assignment as to the order of management. Both arms were six months in duration. Patients on established long term OAT who had internet access were eligible for enrolment. During the supervised PST arm of the study, patients measured their INR at home using the CoaguChek XS® point of care meter, (Roche Diagnostics, UK) either twice weekly, weekly or every two weeks depending on their anticoagulation control. They entered this result along with other information relating to their warfarin therapy (e.g. signs or symptoms of thrombosis or hemorrhage, missed doses, concurrent illnesses, dietary or medication changes etc) onto the CoagCare® (Zycare Inc, Chapel Hill, NC) web page. Patients with a therapeutic INR and no other issues were automatically provided with algorithm-derived dosing and repeat testing instructions. Patients with non-therapeutic results, or symptoms suggestive of thromboembolic or hemorrhagic complications, were prioritized for caregiver review according to problem severity. During the AMS arm, patients were required to attend the clinic every four to six weeks, or more frequently, if clinically indicated. Dosage adjustments were performed by the anticoagulant clinic staff using the laboratory INR and the APEX® (iSOFT, UK) computer decision support software. The primary outcome variable to assess anticoagulation control was the difference in time in therapeutic range (TTR) during the AMS management and supervised PST management period. In addition, the number of INR measurements indicative of serious under- or over-anticoagulation and the number of serious hemorrhagic or thrombotic adverse events were also compared. One hundred and sixty two patients were enrolled over a nine-month period (July 2006–April 2007). The majority of study patients were male (61.4%) and the mean age of the study population was 59.6 +/−14.3 years. One hundred and thirty two (81.5%) patients completed both arms of the study. The mean TTR during the AMS arm was 60.2% +/−19.5%, which increased to 71.4% +/− 13.6% during the PST period (p<0.001). Eighty-seven patients (65.91%) achieved better anticoagulation control during the supervised PST period. Patients measured their INR almost four times more frequently while home-testing giving a mean frequency of INR testing of 4.5 days compared with 17.4 days for the AMS period. Extreme INR values (< 1.5 and > 5.0) occurred more frequently during the AMS arm of the study (6% vs 2.4%, p<0.001). There was no significant difference in the adverse event rate between the two study periods. Table 1.Table 1. Adverse eventsModel of careHemorrhagicThromboembolicAMSGastric bleed (INR 2.5)TIA (INR 2.2)Supervised PSTNoneDVT (INR 1.6)DVT (1.4)Daily time to manage 70 patients ranged from 10 to 45 minutes (mean 23.19+/−9.48 mins/day). This novel system of supervised PST using an internet based expert system improves the clinical effectiveness of OAT when compared with management by a specialized anticoagulant management service.

In-Patient International Normalized Ratio Self-Testing Instruction After Mechanical Heart Valve Implantation

Patient self-testing of the international normalized ratio (INR) has been shown to improve management of anticoagulation with warfarin and reduce risks of thromboembolism and bleeding. Self-testing instruction usually begins several weeks after hospital discharge. We evaluated the feasibility of in-hospital INR self-testing instruction in patients recovering from valve replacement. We instituted an education program on a self-testing device before hospital discharge in 50 adult patients (median age, 54 years; 66% men) undergoing cardiac valve replacement with mechanical prostheses. Patients were monitored for 1 month to assess their ability to self-test and the accuracy of the INR measurements. Self-testing instruction began on postoperative day 4 (range, 1 to 8 days). Each patient had an average of 3.5 teaching sessions; each session lasted approximately 20 minutes. One month after discharge, all patients (98%) but 1 were able to self-test. No patient required interval instruction. One bleeding episode occurred in a patient whose INR exceeded the therapeutic range. Once warfarin doses were stabilized, 5 patients had subtherapeutic INR values on self-testing. The mean INR test result obtained from the coagulometer correlated well with values obtained by laboratory determination (r = 0.79). This evaluation of an in-hospital education program demonstrates that patients are able to learn INR self-testing and that most will continue to use the method without the need for interval instruction. Improved anticoagulation management by early introduction of INR self-testing should reduce thromboembolic and hemorrhagic complications after valve replacement.

Influence of haematocrit on international normalised ratio (INR) differences between a whole blood point-of-care coagulation monitor and reference prothrombin time in plasma

The CoaguChek S system is designed for use in patient self-testing. In this system a whole blood sample without sodium citrate is applied to a test strip containing thromboplastin and iron oxide particles. The detection principle is based on fibrin formation which inhibits and finally stops the movement of the iron oxide particles. In the classic prothrombin time (PT) test, citrate plasma is mixed with thromboplastin and an excess of calcium ions. In the monitoring of vitamin K-antagonist (VKA) treatment, all results are expressed on a common scale, i.e. international normalised ratio (INR). In patients on long-term VKA treatment, INRs were determined by the CoaguChek S system and reference methods for the classic PT. Four different CoaguChek S strip lots were evaluated. The difference in INR between the reference PT and the CoaguChek S system was negatively correlated to the haematocrit of the patients. We conclude that INR differences between CoaguChek S and plasma PT may be explained in part by the haematocrit. The magnitude of the effect of haematocrit, within the reference interval of 0.37 - 0.51, on the INR difference was not greater than approximately 10% for the combined data of the four strip lots. A bias of less than 10% seems to be acceptable clinically.

The Reliability of Point-of-Care (POC) Prothrombin Time Testing - A Comparison of CoaguChek XS® INR Measurements with Hospital Laboratory Monitoring.

Background The development of Point of Care (POC) testing devices enables patients to test their own International Normalised Ratio (INR) at home, and has lead to the development of patient self- testing (PST) programmes. This facilitates more frequent testing of anticoagulation levels which in turn improves time in therapeutic range (TTR) and reduces bleeding and thrombotic complications in patients on oral anticoagulation therapy (OAT).1 External quality control of POC devices is essential to ensure that results are robust. One approach is to collect a venous sample at the same time as POC testing, which is analysed using an appropriate hospital laboratory analyzer. It has been recommended that INR results should be within 0.5 of each other when measured by each method2. However, previous studies have shown that when compared with clinical laboratory values, POC devices may show statistically significant differences between the INR values.3 Aim The aim of this study is primarily to compare TTR and adverse events between two different approaches to OAT management and more specifically in this presentation to examine the intra patient variability of INR measurements performed by two different techniques.Methods 160 patients routinely attending the anticoagulant clinic of Cork University Hospital (CUH) were enrolled to take part in a prospective randomized controlled, cross-over design trial of supervised PST of warfarin therapy using an internet based expert system (Coagcare®, ZyCare, Inc) and POC testing device (CoaguChek XS®, Roche, UK) vs. rountine medical care in CUH. During the 6 months PST arm of the study a venous blood sample was taken from each patient for laboratory determination of the INR on 3 occasions; at enrolment, 2 months and 4 months. This measurement was then compared with the INR measured on the Coaguchek XS® machine using capillary blood from the patient's fingertip.Results 88 patients have being enrolled in the PST arm of the study to date and 454 POC measurements have been compared with laboratory values. Good correlation has been shown between the two methods of INR determination (r2 = 0.8314), however, statistically significant differences did occur (p < 0.005). A Bland and Altman plot showed good agreement between the dual measurements at values between 2.0–3.5 INR units. However there seemed to be increasing disagreement between the two methods as the INR rose above 3.5. Four patients were excluded from the study because the differences in the INR measurements were greater than 0.5 INR units. Conclusion POC testing devices for OAT are reliable and safe. External quality assessment should be inherent to any programme involving these devices. Clinicians involved in the use of POC anticoagulation monitoring should be aware that POC and laboratory values may differ and intervene if there is not adequate correlation between the two INR measurements.

Incorporating patient self-testing into your practice

Patient self-testing (PST) of the INR is still in its infancy in the United States compared to our European colleagues. Information gathered from the four major third-party suppliers of point of care (POC) devices (Quality Assured Services, Reliant, Raytel and Tapestry Medical) estimates the total number of patients performing PST in the United States to be about 20,000, compared to 130,000 in Germany alone. Currently, only about 1% of all warfarin patients in the United States are self-testing. In a survey conducted by Wittkowsky in 2005, 60% of the United States anticoagulation clinics that responded had policies that prohibited self-testing [1]. An informal survey of clinics that have ‡50 patients self-testing revealed that all had certain criteria to be considered when patients are to self-test. Establishing guidelines for PST is crucial for success. The first hurdle a provider must pass before prescribing PST is to make sure that the patient has the motor dexterity to perform the test or a committed caregiver to perform the test. If the patient meets this criterion, the next step is to establish an acceptable method of communication of results to the healthcare provider. It is important to have more than one phone number in your medical record to reach the patient, or, if the patient prefers, email can be a viable alternative. The third hurdle is the most problematic—the financial aspect of PST. Third party companies, Independent Diagnostic Testing Facilities (IDTFs), will process the 2 to 3-page application and determine if your patient has the necessary financial resources for purchasing the monitor and supplies. Medicare has specific criteria for their patient population. Medicare will pay for patients with mechanical heart valves to perform PST. Eligibility requires the patient to have been on anticoagulation for 3 months and to have documented education on the use of the prescribed POC device. Medicare will cover up to one INR test per week, but does not mandate that the patient test weekly. Incorporating patient self-testing into a practice is not difficult. The key is to have a plan for communicating, documenting and scheduling so that patients do not slip through the cracks. The clinics surveyed all have the patient directly communicate with the clinic for INR reporting and dosage adjustments. It is considered a phone management visit. Under Medicare guidelines a physician can bill for every four INR’s that are interpreted/managed using the G2050 code which currently applies a $9.33 charge. The provider of the instrument and supplies is entitled to bill a G2049 for every four INR tests reported which generates a $146.36 charge. Patients may also be responsible to report test results to the third party suppliers in order to assure that they receive supplies in a timely manner and for the companies to recap their cost of supplies. To help the workflow of self-testing patients in our clinic, we devised a questionnaire with all the information we would normally ask at our face-to-face visit. If a health care professional is not available when the patient calls, the clerical staff ask the questions which are all yes and no answers and get a phone number and time that the patient would like to be reached. The message is then given to the professional staff and the visit is completed and the patient scheduled for the next INR check. If the patient does not phone results in on the date scheduled, the nurse in the Disclosure: Trainer for PST for Tapestry Medical.

Economic Evaluation of Point-of-Care Monitoring Devices for Long-Term Oral Anticoagulation Therapy

Rationale: New technology has made it possible for patients on long-term oral anticoagulation therapy (OAT) to be monitored with portable devices, sometimes in their own homes, rather than having to go to a hospital or laboratory to provide blood by venipuncture. The devices have been on the market for the last decade. Those who administer funds for anticoagulation programs need to know how POC devices compare in cost effectiveness with standard laboratory tests. Objectives: The objective of this report is to assess the cost effectiveness of POC monitoring devices for long-term OAT. Methodology: We did a cost effectiveness analysis in a Canadian context using a decision analytic Markov model. We evaluated the two devices available in Canada: CoaguChek® from Roche Diagnostics and ProTime® from the International Technidyne Corporation, from both a societal and a health care payer perspective. We compared standard care to POC use in two settings: anticoagulation clinics and patient self-testing. Probablistic sensitivity analysis was conducted. Results: The study found that from a publicly funded health care perspective, including nursing home costs, using POC monitors in anticoagulation clinics was cost saving compared to conventional therapy. Using the health care perspective and comparing patient self-testing using POCs with conventional therapy, the cost per additional QALY gained with CoaguChek® is $57,595. (ProTime® was not available in Canada for self-testing at the time our analysis was done.) When a societal perspective is adopted and travel and time costs to patients and their caregivers are included, patient self-testing with CoaguChek® is cost saving. Conclusions: From a publicly funded health care perspective, and including nursing-home costs, using CoaguChek® or ProTime® in anticoagulation clinics is cost saving relative to conventional testing. Patient self-testing with CoaguChek® is not cost saving from a health provider perspective. But from a societal perspective patient self-testing may be cost effective when patient and care-giver time and travel costs are considered.

The Feasibility of Home or Patient Self-Testing

The Feasibility of Home or Patient Self-Testing

Multicentre ISI assignment and calibration of the INR measuring range of a new point-of-care system designed for home monitoring of oral anticoagulation therapy

The new CoaguChek XS system is designed for use in patient selftesting. It is the successor of the current CoaguChek S system. The detection principle is based on the amperometric measurement of the thrombin activity initiated by starting the coagulation cascade using a human recombinant thromboplastin. This study was performed to assign the International SEnsitivity Index (ISI) to the new test according to the WHO guidelines for thromboplastins and plasmas used to control anticoagulant therapy, and to establish the measuring range of the new system. At four study sites a total of 90 samples of normal donors and 291 samples of warfarin-, phenprocoumon- or acenocoumarol-treated patients were included in the study. The ISI value of the new test was assigned against the human recombinant reference thromboplastin rTF/95 at each site using the samples from stabilized patients in the International Normalized Ratio (INR) range between 1.5 and 4.5 only. The new point-of-care system's measuring range between 0.8 and 8 INR was calibrated against the mean INR of rTF/95 and AD149 using polynomial regression. ISIs were (CV of the slope): Site 1: ISI 0.99 (1.1%); Site 2: ISI 1.02 (2.0%); Site 3: ISI 1.03 (1.1%); Site 4: ISI 1.00 (1.4%). All regression lines calculated from patient-only data pass through the normal donor data points. All CVs of the slopes of the orthogonal regression lines are well below 3%, thus fulfilling the requirements of the WHO guidelines. The mean ISI for the new CoaguChek XS PT Test is 1.01.

Acceptibility of Patient Self-Testing of Oral Anticoagulation in New Patients.

Monitoring oral anticoagulation therapy (OAT) remains a significant burden on health care resources. Patient self-testing (PST) of OAT using point of care devices may alleviate these demands and improve the quality of treatment. Previous studies have shown limited benefit, as recruitment amongst patients previously established on OAT has proven to be difficult with only around 10–15 % of those invited agreeing to participate, suggesting that PST may only be suitable for a minority of patients. We aimed to assess whether PST is more acceptable to patients if offered at the commencement of treatment. 216 consecutive adults referred to anticoagulation clinics were assessed for their suitability for PST. Exclusion criteria included: short therapeutic duration (e.g. pre-cardioversion); known drug/alcohol abuse; atypical INR target values; language barriers; physical/intellectual impairment. Suitable patients were offered the opportunity to perform PST with 2 training sessions and thereafter monitor their INR every 1–2 weeks using CoaguChek S (Roche Diagnostics). It was noted during recruitment of the first 100 patients, that patients awaiting cardioversion accounted for a large proportion of the patients excluded (15/54, 28%), but many patients awaiting cardioversion received OAT in excess of six months. We therefore modified initial entry criteria, to include those with atrial fibrillation awaiting cardioversion. Of the 116 patients subsequently approached 37 (32%) were then recruited to PST (compared with only 17 cardiac patients from the first 100 enrolled into the study). 98 (45%) patients fulfilled our entry criteria for PST, of whom 54 (25%) consented to PST. Of the 118 ineligible patients: 23 had previously received OAT; 15 were awaiting cardioversion; the expected duration of OAT was less than 6 months in 13 patients; and PST was logistically impractical in 32 other patients. A further 35 were excluded for a wide variety of reasons including non-standard INR ranges, language barriers, discontinuation of OAT and planned surgical procedures. Only two of the 54 patients who started PST elected to return to hospital testing. Overall 53 % (52/98) of eligible patients have continued to self-test. The INR values obtained from these patients showed that their oral anticoagulant control remained stable (mean time in therapeutic range of 71%), and compared favourably to those patients electing to attend our routine anticoagulant clinic. Our data show that patients offered PST as an alternative to routine clinic management during induction of anticoagulation were more likely to participate in PST than established patients. Furthermore, the vast majority of patients (96%) continued to self-test, a higher figure than previous studies involving established patients.

A randomised control trial of patient self‐management of oral anticoagulation compared with patient self‐testing

Several studies suggest that patient self-management (PSM) may improve the quality of oral anticoagulation therapy as measured by time spent within the international normalised ratio (INR) target range. We performed a prospective randomised control trial to determine whether the improvement in quality of treatment afforded by PSM is greater than that achieved by patient self-testing (PST) alone. A total of 104 of 800 eligible patients aged 22-88 years (median = 59.8), attending our hospital anticoagulant clinic and receiving long-term warfarin for >8 months agreed to participate. Patients were randomised to PSM (n = 55) or PST (n = 49). Both groups measured their INR using the CoaguChek S every 2 weeks or more frequently if required, for a period of 6 months. Seventy-seven of 104 (74%) patients completed the study (PSM = 41 and PST = 36). The 'drop out' rates for both groups were similar. There was no significant difference between the percentage time in target therapeutic range for PSM (69.9%) and PST (71.8%). Both groups combined showed a significant improvement over the previous 6 months (71.0% vs. 62.5%; P = 0.04). Changes in time within the therapeutic range in individual patients (+5.86) also showed a significant difference. The quality of warfarin control in both PST and PSM may be superior to that achieved by conventional management in a specialised hospital anticoagulation clinic.

The Impact of Patient Self-Testing of Prothrombin Time for Managing Anticoagulation: Rationale and Design of VA Cooperative Study #481—The Home INR Study (THINRS)

Anticoagulation (AC) with warfarin reduces the risk of thromboembolism (TE) in a variety of applications, yet despite compelling evidence of the value and importance of high quality AC, warfarin remains underused, and dosing is often suboptimal. Approaches to improve AC quality include (1) an AC service (ACS), which allows the physician to delegate day-to-day details of AC management to another provider dedicated to AC care, and (2) incorporating into the treatment plan patient self-testing (PST) under which, after completing a training program, patients perform their own blood testing (typically, using a finger-stick blood analyzer), have dosage adjustments guided by a standard protocol, and forward test results, dosing and other information to the provider. Studies have suggested that PST can improve the quality of AC and perhaps lower TE and bleed rates. The purpose of Department of Veterans Affairs (VA) Cooperative Studies Program (CSP) #481, "The Home INR Study" (THINRS) is to compare AC management with frequent PST using a home monitoring device to high quality AC management (HQACM) implemented by an ACS with conventional monitoring of prothrombin time by international normalized ratio (INR) on major health outcomes. PST in THINRS involves use of an INR monitoring device that is FDA approved for home use. Sites are VA Medical Centers where the ACS has an active roster of more than 400 patients. THINRS includes patients with atrial fibrillation (AF) and/or mechanical heart valve (MHV) expected to be anticoagulated indefinitely. THINRS has two parts. In Part 1, candidates for PST are evaluated for 2 to 4 weeks for their ability to use home monitoring devices. In Part 2, individuals capable of performing PST are randomized to (1) HQACM with testing every 4 weeks and as indicated for out of range values, medication/clinical changes, or (2) PST with testing every week and as indicated for out of range values, medication/clinical changes. The primary outcome measure is event rates, defined as the percent of patients who have a stroke, major bleed, or die. Secondary outcomes include total time in range (TTR), other events (myocardial infarction (MI), non-stroke TE, minor bleeds), competence and compliance with PST, satisfaction with AC, AC associated quality of life (QOL), and cost-effectiveness. To assess the effect of PST frequency on TTR and other outcomes, at selected sites patients randomized to perform PST are assigned one of three test frequencies (weekly, twice weekly, or once every four weeks).

Barriers to Patient Self-Testing of Prothrombin Time: National Survey of Anticoagulation Practitioners

Oral anticoagulation with warfarin requires routine monitoring of prothrombin time, expressed as the international normalized ratio (INR). Patient self-testing for INR is common in Europe but not in the United States. In order to determine the frequency of INR self-testing among patients whose anticoagulant therapy is managed in U.S. anticoagulation clinics, to describe the processes that support this self-testing, and to identify the barriers as experienced by anticoagulation clinic providers, a three-part survey was mailed to 538 anticoagulation specialists in the United States. The response rate was 43.7%. Policies and procedures of almost 60% of anticoagulation clinics prohibited INR self-testing for enrolled patients. In addition, less than 1% of patients being managed by U.S. anticoagulation clinics use self-testing to obtain INR results. Primary barriers were the cost of self-testing instruments (78.7% of respondents), cost of reagent cartridges (60.4%), and fear that self-testing might lead to unintended self-management (35.7%). Over 75% of respondents believed that some reimbursement for the cost of self-testing devices and supplies would increase the likelihood that anticoagulation clinics would recommend INR self-testing.

Patient self‐testing is a reliable and acceptable alternative to laboratory INR monitoring

SAn ageing population and the continuing expansion of clinical indications for coumadin therapy have increased pressure on hospital anticoagulant clinics. One solution is patient self-testing (PST) of the international normalized ratio (INR) using capillary blood samples on point-of-care coagulation monitors at home. We conducted a prospective study to determine whether patients can achieve accurate INR values through PST, using the CoaguChek S (Roche Diagnostics, Lewes, UK). The main outcome measurements were: comparability of INR values obtained by PST and the hospital laboratory, patient acceptability as assessed by a questionnaire and anticoagulant control. Eighty-four patients [53 men, 31 women; median age 59 years (range 26-83)], receiving long-term oral anticoagulation (warfarin), were recruited from our Anticoagulation Clinic. Patients were randomized to weekly self-testing or continuing 4-weekly hospital laboratory monitoring of INR. Comparison of INRs (n = 234) showed no significant differences between the CoaguChek (median INR 3.02) and laboratory testing (median INR 3.07). There was excellent correlation between the two methods (r = 0.95), with 85% of CoaguChek results within 0.5 INR units of the laboratory method. On four occasions, differences of >1 unit INR were obtained, but in each case the patient's anticoagulation was unstable (INR >4.5 by both methods) and the differences in INR would not have altered patient management. 87% of patients found self-testing straightforward, 87% were confident in the result they obtained and 77% preferred self-testing. We conclude that PST is a reliable alternative to hospital clinic attendance and is acceptable to the majority of suitably trained patients.

Efficacy of Patient Self Testing (PST) for Management of the Hypercoagulable Patient.

The PREVENT trial showed strong evidence of the importance of long term low intensity oral anticoagulation therapy (OAT) in patients diagnosed with hyper-coagulable disorders following an initial venous thrombo-embolic event. The current study was designed to compare patient compliance, satisfaction, safety and time in range (TIR) with OAT monitored by either PST or standard laboratory methods. All patients enrolled had a history of at least one hyper-coagulable disorder and had experienced one or more thrombotic episodes prior to enrollment. Patients randomized to the PST arm were directed to test weekly using the ProTime Microcoagulation System (ITC, Edison, NJ); those in the control arm were directed to return to the clinic monthly for Prothrombin time/International Normalized Ratio (PT/INR) testing. Additional testing was encouraged for both groups in response to changes in diet, medication or clinical condition. Of the patients screened for the trial, eight patients randomized to the control arm completed the evaluation period and twenty-three patients randomized to the PST arm have completed at least 6 months of testing. Time in range was determined by the method described by Rosendaal where the INR results between two test dates are assumed to be evenly split between the two test results. The PST patients tested on average once every 9 days (range 5 – 16 days); demonstrating a mean TIR of 73% (range 45 – 90%). The control patients tested at an average frequency of once a month (range 0.3 – 3 months); demonstrating a mean TIR of 73% (range 24 – 96%). There were no statistical differences in the TIR or time above or below range between the two groups. Satisfaction surveys completed at the time of enrollment and after 3 and 6 months of PST showed strong endorsement of PST use. This pilot study demonstrates the utility of PST in the management of OAT in patients with a number of idiopathic coagulopathies and congenital hypercoagulable states (e.g., Protein C deficiency, hyperhomocysteinemia) as an alternative to routine clinical management without compromise to the patient's well-being.