Browsing by Subject "International Normalized Ratio"
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Item Open Access 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).(Journal of thrombosis and thrombolysis, 2010-10) Dolor, Rowena J; Ruybalid, R Lynne; Uyeda, Lauren; Edson, Robert G; Phibbs, Ciaran; Vertrees, Julia E; Shih, Mei-Chiung; Jacobson, Alan K; Matchar, David B; THINRS Site InvestigatorsPrior 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.Item Open Access Association of Preceding Antithrombotic Treatment With Acute Ischemic Stroke Severity and In-Hospital Outcomes Among Patients With Atrial Fibrillation.(JAMA, 2017-03) Xian, Ying; O'Brien, Emily C; Liang, Li; Xu, Haolin; Schwamm, Lee H; Fonarow, Gregg C; Bhatt, Deepak L; Smith, Eric E; Olson, DaiWai M; Maisch, Lesley; Hannah, Deidre; Lindholm, Brianna; Lytle, Barbara L; Pencina, Michael J; Hernandez, Adrian F; Peterson, Eric DImportance:Antithrombotic therapies are known to prevent stroke for patients with atrial fibrillation (AF) but are often underused in community practice. Objectives:To examine the prevalence of patients with acute ischemic stroke with known history of AF who were not receiving guideline-recommended antithrombotic treatment before stroke and to determine the association of preceding antithrombotic therapy with stroke severity and in-hospital outcomes. Design, Setting, and Participants:Retrospective observational study of 94 474 patients with acute ischemic stroke and known history of AF admitted from October 2012 through March 2015 to 1622 hospitals participating in the Get With the Guidelines-Stroke program. Exposures:Antithrombotic therapy before stroke. Main Outcomes and Measures:Stroke severity as measured by the National Institutes of Health Stroke Scale (NIHSS; range of 0-42, with a higher score indicating greater stroke severity and a score ≥16 indicating moderate or severe stroke), and in-hospital mortality. Results:Of 94 474 patients (mean [SD] age, 79.9 [11.0] years; 57.0% women), 7176 (7.6%) were receiving therapeutic warfarin (international normalized ratio [INR] ≥2) and 8290 (8.8%) were receiving non-vitamin K antagonist oral anticoagulants (NOACs) preceding the stroke. A total of 79 008 patients (83.6%) were not receiving therapeutic anticoagulation; 12 751 (13.5%) had subtherapeutic warfarin anticoagulation (INR <2) at the time of stroke, 37 674 (39.9%) were receiving antiplatelet therapy only, and 28 583 (30.3%) were not receiving any antithrombotic treatment. Among 91 155 high-risk patients (prestroke CHA2DS2-VASc score ≥2), 76 071 (83.5%) were not receiving therapeutic warfarin or NOACs before stroke. The unadjusted rates of moderate or severe stroke were lower among patients receiving therapeutic warfarin (15.8% [95% CI, 14.8%-16.7%]) and NOACs (17.5% [95% CI, 16.6%-18.4%]) than among those receiving no antithrombotic therapy (27.1% [95% CI, 26.6%-27.7%]), antiplatelet therapy only (24.8% [95% CI, 24.3%-25.3%]), or subtherapeutic warfarin (25.8% [95% CI, 25.0%-26.6%]); unadjusted rates of in-hospital mortality also were lower for those receiving therapeutic warfarin (6.4% [95% CI, 5.8%-7.0%]) and NOACs (6.3% [95% CI, 5.7%-6.8%]) compared with those receiving no antithrombotic therapy (9.3% [95% CI, 8.9%-9.6%]), antiplatelet therapy only (8.1% [95% CI, 7.8%-8.3%]), or subtherapeutic warfarin (8.8% [95% CI, 8.3%-9.3%]). After adjusting for potential confounders, compared with no antithrombotic treatment, preceding use of therapeutic warfarin, NOACs, or antiplatelet therapy was associated with lower odds of moderate or severe stroke (adjusted odds ratio [95% CI], 0.56 [0.51-0.60], 0.65 [0.61-0.71], and 0.88 [0.84-0.92], respectively) and in-hospital mortality (adjusted odds ratio [95% CI], 0.75 [0.67-0.85], 0.79 [0.72-0.88], and 0.83 [0.78-0.88], respectively). Conclusions and Relevance:Among patients with atrial fibrillation who had experienced an acute ischemic stroke, inadequate therapeutic anticoagulation preceding the stroke was prevalent. Therapeutic anticoagulation was associated with lower odds of moderate or severe stroke and lower odds of in-hospital mortality.Item Open Access At-Home Versus In-Clinic INR Monitoring: A Cost-Utility Analysis from The Home INR Study (THINRS).(Journal of general internal medicine, 2016-09) Phibbs, Ciaran S; Love, Sean R; Jacobson, Alan K; Edson, Robert; Su, Pon; Uyeda, Lauren; Matchar, David B; writing for the THINRS Executive Committee and Site InvestigatorsBackground
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.Item Open Access Does distance modify the effect of self-testing in oral anticoagulation?(The American journal of managed care, 2016-01) Rose, Adam J; Phibbs, Ciaran S; Uyeda, Lauren; Su, Pon; Edson, Robert; Shih, Mei-Chiung; Jacobson, Alan; Matchar, David BObjectives
Patient self-testing (PST) improves anticoagulation control and patient satisfaction. It is unknown whether these effects are more pronounced when the patient lives farther from the anticoagulation clinic (ACC). If the benefits of PST are limited to a subset of patients (those living farther from care), selectively providing PST to that subset could enhance cost-effectiveness.Study design
This is a secondary analysis of a randomized trial of PST versus usual ACC care, which involved 2922 patients of the Veterans Health Administration (VHA).Methods
Our 3 outcomes were the primary composite clinical end point (stroke, major hemorrhage, or death), anticoagulation control (percent time in therapeutic range), and satisfaction with anticoagulation care. We measured the driving distance between the patient's residence and the nearest VHA facility. We divided patients into quartiles by distance and looked for evidence of an interaction between distance and the effect of the intervention on the 3 outcomes.Results
The median driving distance was 12 miles (interquartile range = 6-21). Patients living in the farthest quartile had higher rates of the primary composite clinical end point in both groups compared with patients living in the nearest quartile. For PST, the hazard ratio (HR) was 1.77 (95% CI, 1.18-2.64), and for usual care, the HR was 1.81 (95% CI, 1.19-2.75). Interaction terms did not suggest that distance to care modified the effect of the intervention on any outcome.Conclusions
The benefits of PST were not enhanced among patients living farther from care. Restricting PST to patients living more than a certain distance from the ACC is not likely to improve its cost-effectiveness.Item Open Access Effect of home testing of international normalized ratio on clinical events.(The New England journal of medicine, 2010-10) Matchar, David B; Jacobson, Alan; Dolor, Rowena; Edson, Robert; Uyeda, Lauren; Phibbs, Ciaran S; Vertrees, Julia E; Shih, Mei-Chiung; Holodniy, Mark; Lavori, Philip; THINRS Executive Committee and Site InvestigatorsBackground
Warfarin anticoagulation reduces thromboembolic complications in patients with atrial fibrillation or mechanical heart valves, but effective management is complex, and the international normalized ratio (INR) is often outside the target range. As compared with venous plasma testing, point-of-care INR measuring devices allow greater testing frequency and patient involvement and may improve clinical outcomes.Methods
We randomly assigned 2922 patients who were taking warfarin because of mechanical heart valves or atrial fibrillation and who were competent in the use of point-of-care INR devices to either weekly self-testing at home or monthly high-quality testing in a clinic. The primary end point was the time to a first major event (stroke, major bleeding episode, or death).Results
The patients were followed for 2.0 to 4.75 years, for a total of 8730 patient-years of follow-up. The time to the first primary event was not significantly longer in the self-testing group than in the clinic-testing group (hazard ratio, 0.88; 95% confidence interval, 0.75 to 1.04; P=0.14). The two groups had similar rates of clinical outcomes except that the self-testing group reported more minor bleeding episodes. Over the entire follow-up period, the self-testing group had a small but significant improvement in the percentage of time during which the INR was within the target range (absolute difference between groups, 3.8 percentage points; P<0.001). At 2 years of follow-up, the self-testing group also had a small but significant improvement in patient satisfaction with anticoagulation therapy (P=0.002) and quality of life (P<0.001).Conclusions
As compared with monthly high-quality clinic testing, weekly self-testing did not delay the time to a first stroke, major bleeding episode, or death to the extent suggested by prior studies. These results do not support the superiority of self-testing over clinic testing in reducing the risk of stroke, major bleeding episode, and death among patients taking warfarin therapy. (Funded by the Department of Veterans Affairs Cooperative Studies Program; ClinicalTrials.gov number, NCT00032591.).Item Open Access Home monitoring of warfarin effects.(The New England journal of medicine, 2011-01) Lippi, Giuseppe; Franchini, MassimoItem Open Access Risks of intracranial hemorrhage among patients with acute ischemic stroke receiving warfarin and treated with intravenous tissue plasminogen activator.(JAMA, 2012-06) Xian, Y; Liang, L; Smith, EE; Schwamm, LH; Reeves, MJ; Olson, DM; Hernandez, AF; Fonarow, GC; Peterson, EDIntravenous tissue plasminogen activator (tPA) is known to improve outcomes in ischemic stroke; however, patients receiving long-term chronic warfarin therapy may face an increased risk for intracranial hemorrhage when treated with tPA. Although current guidelines endorse administering intravenous tPA to warfarin-treated patients if their international normalized ratio (INR) is 1.7 or lower, there are few data on safety of intravenous tPA in warfarin-treated patients in clinical practice.To determine the risk of symptomatic intracranial hemorrhage (sICH) among patients with ischemic stroke treated with intravenous tPA who were receiving warfarin vs those who were not and to determine this risk as a function of INR.Observational study, using data from the American Heart Association Get With The Guidelines-Stroke Registry, of 23,437 patients with ischemic stroke and with INR of 1.7 or lower, treated with intravenous tPA in 1203 registry hospitals from April 2009 through June 2011.Symptomatic intracranial hemorrhage. Secondary end points include life-threatening/serious systemic hemorrhage, any tPA complications, and in-hospital mortality.Overall, 1802 (7.7%) patients with stroke treated with tPA were receiving warfarin (median INR, 1.20; interquartile range [IQR], 1.07-1.40). Warfarin-treated patients were older, had more comorbid conditions, and had more severe strokes. The unadjusted sICH rate in warfarin-treated patients was higher than in non-warfarin-treated patients (5.7% vs 4.6%, P < .001), but these differences were not significantly different after adjustment for baseline clinical factors (adjusted odds ratio [OR], 1.01 [95% CI, 0.82-1.25]). Similarly, there were no significant differences between warfarin-treated and non-warfarin-treated patients for serious systemic hemorrhage (0.9% vs 0.9%; adjusted OR, 0.78 [95% CI, 0.49-1.24]), any tPA complications (10.6% vs 8.4%; adjusted OR, 1.09 [95% CI, 0.93-1.29]), or in-hospital mortality (11.4% vs 7.9%; adjusted OR, 0.94 [95% CI, 0.79-1.13]). Among warfarin-treated patients with INRs of 1.7 or lower, the degree of anticoagulation was not statistically significantly associated with sICH risk (adjusted OR, 1.10 per 0.1-unit increase in INR [95% CI, 1.00-1.20]; P = .06).Among patients with ischemic stroke, the use of intravenous tPA among warfarin-treated patients (INR ≤1.7) was not associated with increased sICH risk compared with non-warfarin-treated patients.Item Open Access Self-monitoring of oral anticoagulation: systematic review and meta-analysis of individual patient data.(Lancet (London, England), 2012-01) Heneghan, Carl; Ward, Alison; Perera, Rafael; Self-Monitoring Trialist Collaboration; Bankhead, Clare; Fuller, Alice; Stevens, Richard; Bradford, Kairen; Tyndel, Sally; Alonso-Coello, Pablo; Ansell, Jack; Beyth, Rebecca; Bernardo, Artur; Christensen, Thomas Decker; Cromheecke, ME; Edson, Robert G; Fitzmaurice, David; Gadisseur, Alain PA; Garcia-Alamino, Josep M; Gardiner, Chris; Hasenkam, J Michael; Jacobson, Alan; Kaatz, Scott; Kamali, Farhad; Khan, Tayyaba Irfan; Knight, Eve; Körtke, Heinrich; Levi, Marcel; Matchar, David; Menéndez-Jándula, Bárbara; Rakovac, Ivo; Schaefer, Christian; Siebenhofer, Andrea; Souto, Juan Carlos; Sunderji, Rubina; Gin, Kenneth; Shalansky, Karen; Völler, Heinz; Wagner, Otto; Zittermann, ArminBackground
Uptake of self-testing and self-management of oral anticoagulation [corrected] has remained inconsistent, despite good evidence of their effectiveness. To clarify the value of self-monitoring of oral anticoagulation, we did a meta-analysis of individual patient data addressing several important gaps in the evidence, including an estimate of the effect on time to death, first major haemorrhage, and thromboembolism.Methods
We searched Ovid versions of Embase (1980-2009) and Medline (1966-2009), limiting searches to randomised trials with a maximally sensitive strategy. We approached all authors of included trials and requested individual patient data: primary outcomes were time to death, first major haemorrhage, and first thromboembolic event. We did prespecified subgroup analyses according to age, type of control-group care (anticoagulation-clinic care vs primary care), self-testing alone versus self-management, and sex. We analysed patients with mechanical heart valves or atrial fibrillation separately. We used a random-effect model method to calculate pooled hazard ratios and did tests for interaction and heterogeneity, and calculated a time-specific number needed to treat.Findings
Of 1357 abstracts, we included 11 trials with data for 6417 participants and 12,800 person-years of follow-up. We reported a significant reduction in thromboembolic events in the self-monitoring group (hazard ratio 0·51; 95% CI 0·31-0·85) but not for major haemorrhagic events (0·88, 0·74-1·06) or death (0·82, 0·62-1·09). Participants younger than 55 years showed a striking reduction in thrombotic events (hazard ratio 0·33, 95% CI 0·17-0·66), as did participants with mechanical heart valve (0·52, 0·35-0·77). Analysis of major outcomes in the very elderly (age ≥85 years, n=99) showed no significant adverse effects of the intervention for all outcomes.Interpretation
Our analysis showed that self-monitoring and self-management of oral coagulation is a safe option for suitable patients of all ages. Patients should also be offered the option to self-manage their disease with suitable health-care support as back-up.Funding
UK National Institute for Health Research (NIHR) Technology Assessment Programme, UK NIHR National School for Primary Care Research.Item Open Access 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.(Journal of thrombosis and thrombolysis, 2015-07) Matchar, David B; Love, Sean R; Jacobson, Alan K; Edson, Robert; Uyeda, Lauren; Phibbs, Ciaran S; Dolor, Rowena JAnticoagulation (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.