Determinants of oral anticoagulation control in new warfarin patients: analysis using data from Clinical Practice Research Datalink

Effectiveness and safety of direct oral anticoagulants among patients with non-valvular atrial fibrillation and liver disease: A multinational cohort study

BACKGROUND AND AIMS

The effects of direct oral anticoagulants (DOACs) in patients with non-valvular atrial fibrillation (NVAF) and liver disease remain poorly understood. Our multinational cohort study assessed the effectiveness and safety of DOACs in this high-risk population.

METHODS

We assembled two population-based cohorts in United Kingdom and in Québec of NVAF patients with liver disease initiating DOACs or vitamin K antagonists (VKAs) between 2011 and 2020. Using an as-treated exposure definition, we compared DOACs to VKAs and apixaban to rivaroxaban. After inverse probability of treatment weighting, Cox proportional hazards models estimated site-specific hazard ratios (HRs) and 95 % confidence intervals (CIs) of ischemic stroke and major bleeding. Site-specific estimates were pooled using random-effects models. Analyses were repeated among NVAF patients with cirrhosis.

RESULTS

There were 11,881 NVAF patients with liver disease (2683 with cirrhosis). Among those, 8815 initiated DOACs (4414 apixaban, 2497 rivaroxaban) and 3696 VKAs. The HRs (95 % CIs) for DOACs compared to VKAs were 1.01 (0.76-1.34) for ischemic stroke and 0.87 (0.77-0.99) for major bleeding. Results were consistent among patients with cirrhosis. The HRs (95 % CIs) for apixaban compared to rivaroxaban were 0.85 (0.60-1.20) for ischemic stroke and 0.80 (0.68-0.95) for major bleeding. This decreased bleeding risk was not observed among patients with cirrhosis (HR, 1.01; 95 % CI 0.72-1.43).

CONCLUSIONS

Among NVAF patients with liver disease, DOACs were as effective and slightly safer than VKAs, and apixaban was as effective but safer than rivaroxaban. The safety benefit with apixaban was not present among patients with cirrhosis.

Direct Oral Anticoagulation Versus Warfarin in Left Ventricular Thrombus: Pooled Analysis of Randomized Controlled Trials

Patients with impaired left ventricular (LV) function can develop LV thrombus, a potentially life-threatening condition due to risk of stroke and embolization. Conventional treatment with vitamin K antagonists (VKAs; e.g., warfarin) puts patients at risk of bleeding, and the use of direct oral anticoagulants (DOACs) appears promising, although data are scant. We searched the published English language literature for randomized controlled trials (RCTs) comparing DOACs with VKAs in LV thrombus. End points were failure to resolve, thromboembolic events (stroke, embolism), bleeding, or any adverse event (composite of thromboembolism or bleeding), or all-cause death. Data were pooled and analyzed in hierarchical Bayesian models. In three eligible RCTs, 141 patients were studied during an average of 4.6 months (53.8 patient-years; n = 71 assigned to DOAC, n = 70 assigned to VKA). A similar number of patients in each treatment arm demonstrated failure to resolve (DOAC: 14/71 vs. VKA: 15/70) and death events (3/71 vs. 4/70). However, patients on DOACs suffered fewer strokes/thromboembolic events (1/71 vs. 7/70; log odds ratio [OR], -2.02 [95% credible interval (CI95 ), -4.53 to -0.31]) and fewer bleeding events (2/71 vs. 9/70; log OR, -1.62 [CI95 , -3.43 to -0.26]), leading to fewer patients on DOACs with any adverse event versus VKAs (3/71 vs. 16/70; log OR, -1.93 [CI95 , -3.33 to -0.75]). In conclusion, pooled analysis of RCT data favors DOACs over VKAs in patients with LV thrombus in terms of both efficacy and safety.

Quality of Anticoagulation With Phenprocoumon and Warfarin in Left Ventricular Assist Device Patients: A Multicenter Study

VISUAL ABSTRACT

of key results. INR, international normalized ratio; TTR, time in therapeutic range; PTR, percentage of tests in range; HRAE, hemocompatibility-related adverse event; FFUV, first follow-up visit; GIB, gastrointestinal bleeding; HR, hazard ratio.http://links.lww.com/ASAIO/A961.

Determination of Factors Affecting Time in Therapeutic Range in Patients on Warfarin Therapy

BACKGROUND

The effectiveness and safety of warfarin depend on maintaining an international normalized ratio (INR) within the therapeutic range. Time in Therapeutic Range (TTR) is defined as the percentage of time a patient's INR is within the therapeutic range.

OBJECTIVE

We sought to determine the factors affecting good TTR in patients on warfarin therapy.

METHODS

This was a descriptive cross-sectional study conducted in a single tertiary care center. Good anticoagulation control was defined as TTR ≥65%.

RESULTS

The study population consisted of 518 patients. The mean age was 57.6 ± 12.3 (19-87) and 54.4% of the patients were female. 47.5% patients achieved good anticoagulation control (TTR ≥65%). The mean Medication Adherence Report Scale (MARS) score was significantly higher in patients with good TTR (23.5 ± 1.9 vs. 22.8 ± 2.1, p = .002). Only 40.2% of the patients received education on warfarin. In multivariable analyses, the duration of warfarin therapy >10 years (OR: 2.27, 95% CI: 1.34-3.84, p = .002) and MARS score (OR: 1.22, 95% CI: 1.09-1.35, p < .001) were found to be the independent predictors of the good anticoagulation control.

CONCLUSION

Duration of warfarin therapy >10 years and MARS score were the independent predictors of good anticoagulation control.

Effect of current smoking on ischemic events in patients with atrial fibrillation taking vitamin K antagonist

Purpose

We investigated the association between current smoking and clinical outcomes in patients with atrial fibrillation (AF) prescribed vitamin K antagonist (VKA).

Methods

We conducted a retrospective study at 71 centers in Japan. The inclusion criterion was taking a VKA for AF. Exclusion criteria were mechanical heart valves or history of pulmonary thrombosis or deep vein thrombosis. Consecutive patients were registered in February 2013 and followed until February 2017. The primary outcomes included ischemic events and major bleedings. The secondary outcomes were ischemic stroke, hemorrhagic stroke, and all-cause mortality.

Results

A total of 7826 patients were included, with a mean age of 73 years; 5274 (67%) were men. The adjusted hazard ratios (HRs; 95% confidence intervals [CIs]) of current smokers relative to non-current smokers for ischemic events and major bleedings were 1.64 (1.05-2.57) and 1.09 (0.72-1.65), respectively. The adjusted HRs (95% CIs) of current smokers relative to non-current smokers for ischemic stroke, hemorrhagic stroke, and all-cause mortality were 1.65 (1.03-2.64), 0.52 (0.12-2.15), and 1.26 (0.83-1.92), respectively.

Conclusions

There were significant associations between current smoking and ischemic events or ischemic stroke in patients with AF on VKA.

Evaluation of Anticoagulation Control among Patients Taking Warfarin in University of Gondar Hospital, Northwest Ethiopia

INTRODUCTION

Warfarin is a widely used oral anticoagulant in clinical practice. It has variable intraindividual and interindividual dose response and a narrow therapeutic index. Therefore, it requires frequent and regular international normalized ratio (INR) determination to maintain the INR within the therapeutic range. The study evaluated parameters of anticoagulation control among patients on warfarin.

METHODS

A cross-sectional study was conducted at University of Gondar hospital. A consecutive sampling method was used to recruit study subjects. The anticoagulation control was evaluated by determining the proportion of desired INRs and the proportion of time spent in the therapeutic range (TTR). Logistic regression analysis was used to identify associated factors with adequate TTR. A P value <0.05 was used to declare significant association.

RESULT

A total of 338 study subjects were included in the study. The mean age of patients was 48.8 (SD = 16.4) years. Atrial fibrillation was the commonest indication for warfarin therapy. One-third (33%) of study subjects achieved the desired INRs of 2.0-3.0, while about one-tenth (13%) of patients attained good INR control (TTR ≥ 65%). Multivariate logistic regression analysis revealed no significant association of sociodemographic and clinical characteristics with good TTR outcome.

CONCLUSION

The level of anticoagulation control with warfarin among study subjects was very low. The authors recommend to implement a validated warfarin-dose titration protocol and to establish anticoagulation clinics to mitigate the low anticoagulation level.

Anticoagulation Control in Different Ethnic Groups Receiving Vitamin K Antagonist for Stroke Prevention in Atrial Fibrillation

Vitamin K antagonist such as warfarin reduces the risk of stroke in atrial fibrillation (AF) patients. Since warfarin has a narrow therapeutic index, its administration needs to be regularly monitored to avoid any adverse clinical outcomes such as stroke and bleeding. The quality of anticoagulation control with warfarin therapy can be measured by using time in therapeutic range (TTR). This review focuses on the prevalence of AF, quality of anticoagulation control (TTR) and adverse clinical outcome in AF patients within different ethnic groups receiving warfarin therapy for stroke prevention. A literature search was conducted in Embase and PubMed using keywords of “prevalence,” “atrial fibrillation,” “stroke prevention,” “oral anticoagulants,” “warfarin,” “ethnicities,” “race” “time in therapeutic range,” “adverse clinical outcome,” “stroke, bleeding.” Articles published by 1st February 2020 were included. Forty-one studies were included in the final review consisting of AF prevalence (n = 14 studies), time in therapeutic range (n = 18 studies), adverse clinical outcome (n = 9 studies) within different ethnic groups. Findings indicate that higher prevalence of AF but better anticoagulation control among the Whites as compared to other ethnicities. Of note, non-whites had higher risk of strokes and bleeding outcomes while on warfarin therapy. Addressing disparities in prevention and healthcare resource allocation could potentially improve AF-related outcomes in minorities.

Stability of vitamin K antagonist anticoagulation after COVID-19 diagnosis

BACKGROUND

Coagulopathy has been reported in severely ill patients with coronavirus disease 2019 (COVID-19). It is unclear whether outpatients with COVID-19 who are treated with vitamin K antagonists (VKAs) have unstable anticoagulation.

OBJECTIVE

To assess the stability of VKA therapy in patients with COVID-19 through a case-crossover study.

METHODS

Between February and July 2020, we included patients who tested positive for COVID-19 from two anticoagulant clinics in the Netherlands. We collected international normalized ratios (INRs) determined between 26 weeks before infection and 12 weeks after. Time in therapeutic range (TTR) and the variance growth rate (VGR) were calculated within patients.

RESULTS

Fifty-one patients with COVID-19 (mean age, 84 years) were included, of whom 15 (29%) were men. Mean TTR in the 26 weeks before COVID-19 was 80% (95% confidence interval [CI], 75-85) compared to 59% (95% CI, 51-68) in the 6 weeks after infection. Mean TTR difference was -23% (95% CI, -32 to -14) with a time above therapeutic range of 38% (95% CI, 30-47) in the 6 weeks after infection. The TTR rose again to 79% (95% CI, 69-89) between 6 and 12 weeks after infection. Also, VGR increased, with a mean increase of 4.8 (95% CI, 2.1-7.5) in the 6 weeks after infection. In the 26 weeks before infection, we registered 19 of 641 (3%) of INR ≥5.0 compared with 35 of 247 (14%) in the 6 weeks after (risk ratio, 4.4; 95% CI, 2.7-7.3).

CONCLUSIONS

COVID-19 is associated with a strong decrease in TTR and in therapeutic stability in patients taking VKAs. Additional monitoring in these patients is advised to maximize therapeutic stability.

Patients’ time in therapeutic range on warfarin among atrial fibrillation patients in Warfarin Medication Therapy Adherence Clinic

BACKGROUND

The quality of warfarin therapy can be determined by the time in the therapeutic range (TTR) of international normalized ratio (INR). The estimated minimum TTR needed to achieve a benefit from warfarin therapy is ≥ 60%.

AIM

To determine TTR and the predictors of poor TTR among atrial fibrillation patients who receive warfarin therapy.

METHODS

A retrospective observational study was conducted at a cardiology referral center in Selangor, Malaysia. A total of 420 patients with atrial fibrillation and under follow-up at the pharmacist led Warfarin Medication Therapeutic Adherence Clinic between January 2014 and December 2018 were included. Patients’ clinical data, information related to warfarin therapy, and INR readings were traced through electronic Hospital Information system. A data collection form was used for data collection. The percentage of days when INR was within range was calculated using the Rosendaal method. The poor INR control category was defined as a TTR < 60%. Predictors for poor TTR were further determined by using logistic regression.

RESULTS

A total of 420 patients [54.0% male; mean age 65.7 (10.9) years] were included. The calculated mean and median TTR were 60.6% ± 20.6% and 64% (interquartile range 48%-75%), respectively. Of the included patients, 57.6% (n = 242) were in the good control category and 42.4% (n = 178) were in the poor control category. The annual calculated mean TTR between the year 2014 and 2018 ranged from 59.7% and 67.3%. A high HAS-BLED score of ≥ 3 was associated with poor TTR (adjusted odds ratio, 2.525; 95% confidence interval: 1.6-3.9, P < 0.001).

CONCLUSION

In our population, a high HAS-BLED score was associated with poor TTR. This could provide an important insight when initiating an oral anticoagulant for these patients. Patients with a high HAS-BLED score may obtain less benefit from warfarin therapy and should be considered for other available oral anticoagulants for maximum benefit.

Tele-pharmacy Anticoagulation Clinic During COVID-19 Pandemic: Patient Outcomes

Introduction: It is well-established that clinical pharmacist-managed anticoagulation services achieve superior anticoagulation control, with a positive impact. At King Abdulaziz Medical City (KAMC), Riyadh, Saudi Arabia, the structure of anticoagulation management is a pharmacist-managed specialty service. With the current COVID-19 situation, measures were taken to assure the continuity of patient care by establishing tele-pharmacy anticoagulation clinics. Materials and Methods: This was a prospective study with patients prescribed anticoagulation and followed up for 3 months. Since establishing the anticoagulation virtual clinic in March 2020, 270 patients were recruited in the study. The data collected included age, gender, comorbidities, indication for anticoagulation, intended duration of treatment, warfarin dose, testing of International Normalized Ratio (INR), INR target, range of INR values, time INR that was within the therapeutic range (TTR), and complications of therapy (bleeding and/or bruises). The patients were asked to complete the pharmacist satisfaction survey (PSS) after their consultation to assess patient satisfaction with the new virtual consultation system. Linguistic and cultural validation was conducted for the questionnaire. Results: A total of 270 patients were included in the study. The mean percentage of overall INR values in the range was 59.39% ± 32.84, and the mean time with the overall INR was within the therapeutic range 57.81% ± 32.08. Thirty-one percent of the sample had good anticoagulation control (time in therapeutic range >70%). The median satisfaction score was 32 (IQR 28-36) with a maximum score of 40. Conclusion: This is the first study to assess the tele-pharmacy anticoagulation clinic's efficiency and patient satisfaction in Saudi Arabia during the COVID-19 pandemic. This type of consultation was as effective as face-to-face consultations. The study also highlighted that though the reduction in the cost of care was not substantial, there was a significant increase in resource (clinical pharmacist) utilization as a result of this model. The adoption of tele-pharmacy resulted in time savings for the clinical pharmacists who can be utilized in many other improvement projects in adult ambulatory clinics to ensure the delivery of better quality and safe patient care.

Patient-related factors associated with oral anticoagulation control: a population-based cohort study

OBJECTIVES

Time in therapeutic range (TTR) of ≥70% is a commonly used indicator of optimal anticoagulation control. This study aimed to determine the patterns and predictors of anticoagulation control in a population-based cohort of new users of warfarin.

METHODS

This was a retrospective cohort study. All adults (age ≥18 years) who had been newly initiated on warfarin therapy between January 2006 and March 2011were selected from administrative health databases. TTR was calculated using the Rosendaal method. Multivariable logistic regression models were used to identify patient-related factors associated with optimal TTR. Predictors of patients spending >30% of time above and below the therapeutic international normalised ratio (INR) range were also examined.

KEY FINDINGS

A total of 6032 patients were included in this study. The mean TTR was 54.1 ± 18.8%, and 82.3% of patients had subthreshold TTR (<70%). Compared with New Zealand Europeans, Māori and Pacific people had decreased odds of achieving optimal TTR and increased odds of spending >30% of time below the therapeutic INR range. Patients aged 65-74 years and 75 years or older had increased odds of achieving optimal TTR but decreased odds of spending >30% of time below the therapeutic INR range than those <65 years. Compared with those living in the least socioeconomically deprived areas, those living in the most deprived areas had decreased odds of achieving optimal TTR.

CONCLUSIONS

Anticoagulation control with warfarin is suboptimal in routine care in New Zealand. Age, ethnicity and deprivation index were significant predictors of TTR. It is important to ensure equitable access to appropriate, high-quality care for those living in deprived areas and those from ethnic minority groups.

The effect of reinforcing an educational programme using telephone follow-up on health-related quality of life of individuals using warfarin: A randomised controlled trial

OBJECTIVES

To evaluate the effect of reinforcing an educational programme through telephone follow-up on health-related quality of life and anxiety and depression symptoms in individuals starting warfarin therapy.

BACKGROUND

Educational interventions have improved quality of life in individuals using warfarin. Few studies have examined the addition of telephone follow-up to enhance educational interventions.

DESIGN

Randomised controlled trial in outpatient setting.

METHODS

Hospitalised adults starting warfarin therapy who agreed to participate received an educational programme about the warfarin treatment. At discharge, they were randomised to receive either five telephone follow-up calls (intervention) or no telephone calls (controls). Both groups were evaluated for health-related quality of life (using Duke Anticoagulation Satisfaction Scale) and symptoms of anxiety and depression (using Hospital Anxiety and Depression Scale) at three and six months post-discharge. Groups were compared at each time by independent-samples t test, and over time by repeated-measures analysis of variance, with time (three and six months), groups (intervention and control) and an interaction between time and group as factors. Level of significance was set at 0.05. The Consolidated Standards of Reporting Trials was used for reporting.

RESULTS

Fifty-two individuals (26 per group) completed the study. There were no statistical differences between groups in health-related quality of life, anxiety and depression symptoms, at both times post-discharge. Participants who received follow-up telephone calls reported better positive psychological impact (a subscale of quality of life) than controls.

CONCLUSIONS

Reinforcing an educational programme with telephone follow-ups did not have an overall effect on health-related quality of life of individuals using warfarin but promoted positive psychological impact.

RELEVANCE TO CLINICAL PRACTICE

The low cost of reinforcing educational programmes with telephone calls and the improvement in positive psychological aspects indicate that this type of intervention is still a promising intervention that could be further investigated and improved.

Time in therapeutic range is lower in women than in men and is not explained by differences in age or comorbidity

BACKGROUND

Time in therapeutic range (TTR) measures the stability of the international normalized ratio in patients on vitamin K antagonists (VKA). Low values are associated with poor outcomes. Women were shown to have lower TTR than men, but the causes are poorly defined. It was suggested that women on VKA are older and more morbid than men, and this could affect the stability of anticoagulation. We aimed to identify variables that affect TTR differently in women and men.

MATERIALS AND METHODS

This is a retrospective study in patients referred to a University hospital anticoagulant clinic. Age, sex, comorbidities, number of daily medications, indication and type of anticoagulant, weekly dosage and distribution, were derived from electronic records. Differences by sex and regression analysis to identify significant modulators of TTR were computed.

RESULTS

1182 women and 1281 men on VKA were studied. Women were older than men (81.5 yrs. ± 11.2 vs 78.4 yrs. ± 12.2), and had lower TTR (65% ± 20.3 vs 69% ± 19.8). Comorbidity was similar between sexes and negatively affected TTR in both. Mechanical valves as an indication to anticoagulation and acenocoumarol as an anticoagulant as opposed to warfarin had a strong negative influence on TTR, while age increased TTR. Being a man rather than a woman afforded more than three TTR points. Number of medications and average anticoagulant dose were equal between sexes.

DISCUSSION

Women have a lower TTR than men, on average below the safety threshold. They were indeed older, but age positively influenced TTR. Since women and men were equally comorbid, neither age nor disease explains differences in TTR. None of the other variables included in the study could explain the gender gap in TTR. Since women are at increased risk of cardioembolic stroke in atrial fibrillation, an effort at defining other causes for the observed differences, closer monitoring and switching to direct anticoagulants whenever possible is warranted.

The Effects of Educational Programs on Knowledge, International Normalized Ratio, Warfarin Adherence, and Warfarin-Related Complications in Patients Receiving Warfarin Therapy: An Integrative Review

BACKGROUND

Education is considered a crucial element in anticoagulation management for patients with atrial fibrillation, valvular disease, ischemic heart disease, and venous thromboembolism. However, the effects of education on the patients prescribed warfarin are seldom investigated.

OBJECTIVES

This integrative review was conducted to explore the effects of educational programs on patients prescribed warfarin for the aforementioned cardiovascular diseases and to identify the components of effective programs.

METHODS

A systematic search of clinical trials was performed in 8 databases from inception to August 2020. Two reviewers performed the eligibility assessment, methodological evaluation, and data extraction. A total of 9 studies were included and analyzed via narrative synthesis.

RESULTS

Nine studies involving a combined total of 1335 patients were included in the review. The findings suggest that educational programs have potential benefits related to international normalized ratio control and warfarin knowledge. However, their effects on major bleeding and thromboembolic events are unremarkable. Stronger evidence is recommended to confirm these findings, and the limited evidence examining the effects of education on warfarin adherence, minor bleeding, abnormal international normalized ratio, readmission rate, and warfarin-related mortality requires further exploration. Verbal education supported by written materials was the main educational delivery mode. A lecture length of approximately 45 minutes was likely appropriate. Notably, the integration of educational strategies, application of follow-up interventions and monitoring measures, adoption of psychological theories in program development, and inclusion of nurses or pharmacists in program conduction seemed to be effective program components.

CONCLUSIONS

The effects of educational programs on patients prescribed warfarin mainly for atrial fibrillation, valvular disease, ischemic heart disease, and venous thromboembolism remain inconclusive. Further research using randomized controlled trials is warranted.

Risk factors associated with warfarin overdose and complications related to warfarin overdose in the emergency department

The aim of this study was to investigate risk factors of bleeding and mortality in patients with warfarin overdose (WOD). Totally, 783 patients were included, of which, 272 patients (34.7%) with an INR below 5,364 patients (46.5%) with an INR between 5-10, and 147 patients (18.8%) with an INR of 10 or above. Demographic, clinical, and laboratory findings of the patients were obtained from the Real Life Data Provision Center and Hospital Information Management System. Admittance in autumn (OR = 1.75; p = 0.012), INR = 5-10 (OR = 2.65; p < 0.001), INR ≥ 10 (OR = 9.06; p < 0.001), and antiplatelet use alongside warfarin (OR = 1.93; p < 0.001) were found to be independent risk factors for bleeding in this study. The age (OR= 1.03; p = 0.005), bleeding (OR = 1.69; p = 0.020), primary hypertension (OR = 1.72; p = 0.031), and INR ≥ 10 (OR = 2.02; p = 0.025) were found to be independent risk factors for mortality. The cutoff value for INR in predicting bleeding was found to be >6.35 with 74.2% sensitivity and 72.7% specificity. The significant risk factors were determined in WOD development. INR level, autumn, and antiplatelet use were independently associated with bleeding due to WOD. In addition, bleeding, hypertension and INR levels were independently related to in-hospital-mortality due to WOD.

Wild P, H. Prochaska J. Telemedicine-Based Specialized Care Improves the Outcome of Anticoagulated Individuals with Venous Thromboembolism-Results from the thrombEVAL Study

Venous thromboembolism (VTE) is a life-threatening disease with risk of recurrence. Oral anticoagulation (OAC) with vitamin K antagonists (VKA) is effective to prevent thromboembolic recurrence. We aimed to investigate the quality of OAC of VTE patients in regular medical care (RMC) compared to a telemedicine-based coagulation service (CS). The thrombEVAL study (NCT01809015) is a prospective, multi-center study to investigate OAC treatment (recruitment: January 2011-March 2013). Patients were evaluated using clinical visits, computer-assisted personal interviews, self-reported data and laboratory measurements according to standard operating procedures. Overall, 360 patients with VTE from RMC and 254 from CS were included. Time in therapeutic range (TTR) was higher in CS compared to RMC (76.9% (interquartile range [IQR] 63.2-87.1%) vs. 69.5% (52.3-85.6%), p < 0.001). Crude rate of thromboembolic events (rate ratio [RR] 11.33 (95% confidence interval [CI] 1.85-465.26), p = 0.0015), clinically relevant bleeding (RR 6.80 (2.52-25.76), p < 0.001), hospitalizations (RR 2.54 (1.94-3.39), p < 0.001) and mortality under OAC (RR 5.89 (2.40-18.75), p < 0.001) were consistently higher in RMC compared with CS. Patients in RMC had higher risk for primary outcome (clinically relevant bleedings, thromboembolic events and mortality, hazard ratio [HR] 5.39 (95%CI 2.81-10.33), p < 0.0001), mortality (HR 5.54 (2.22-13.84), p = 0.00025), thromboembolic events (HR 6.41 (1.51-27.24), p = 0.012), clinically relevant bleeding (HR 5.31 (1.89-14.89), p = 0.0015) and hospitalization (HR 1.84 (1.34-2.55), p = 0.0002). Benefits of CS care were still observed after adjusting for comorbidities and TTR. In conclusion, anticoagulation quality and outcome of VTE patients undergoing VKA treatment was significantly better in CS than in RMC. Patients treated in CS had lower rates of adverse events, hospitalizations and lower mortality. CS was prognostically relevant, beyond providing advantages of improved international ratio (INR) monitoring.

Anticoagulation control in different ethnic groups receiving vitamin K antagonist therapy for stroke prevention in atrial fibrillation

BACKGROUND

Efficacy and safety of vitamin K antagonists (VKAs) is optimised in atrial fibrillation (AF) patients when the International Normalised Ratio (INR) is 2.0-3.0. Anticoagulation control comparing different ethnic groups is limited, although epidemiological studies suggest poorer INR control in non-white cohorts.

METHODS

VKA control was assessed retrospectively by time-in-the-therapeutic range (TTR) (Rosendaal method) and percentage INR-in-range (PINRR) in 991 White, Afro-Caribbean and South-Asian AF patients [overall mean (SD) age 71.6 (9.4) years; 55% male; mean (SD) CHA₂DS₂-VASc score 3.4 (1.6)] over a median (IQR) follow-up of 5.2 (3.2-7.0) years.

RESULTS

Compared to Whites, mean (SD) TTR and PINRR were significantly lower in South-Asians [TTR 67.9% vs. 60.5%; PINRR 58.8% vs. 51.6%, respectively] and Afro-Caribbeans [TTR 67.9% vs. 61.3%; PINRR 58.8% vs. 53.1%, respectively], despite similar INR monitoring intensity. Logistic regression revealed non-white ethnicity [OR 2.62; 95% Confidence Interval [CI] (1.67-4.10) and OR 3.47 (1.44-8.34)] and anaemia [OR 1.65 (1.00-2.70) and OR 6.27 (1.89-20.94)] as independent predictors of both TTR and PINRR < 70%, respectively. At follow-up, 329 (33.2%) patients experienced ≥1 major adverse clinical event. Cardiovascular hospitalisation was significantly higher among South-Asians (32.3%) compared to the Whites and Afro-Caribbeans (21.3% vs 25.6% respectively).

CONCLUSIONS

Ethnic disparities in quality of anticoagulation control are evident, with South-Asians and Afro-Caribbeans having poorer control compared to Whites, despite similar intensity INR monitoring. Non-white ethnicity remained the strongest independent predictor of poor TTR and PINRR. Interventions to improve anticoagulation control need to be implemented, particularly targeting ethnic minority patients.

Is the time in therapeutic range on coumarins predicted by previous time in therapeutic range?

BACKGROUND

The benefit of vitamin K antagonists depends on the time within the therapeutic range (TTR). A patient's previous TTR could be a factor in the decision to change the anticoagulation regimen. However, the predictive value of a previous TTR for a future TTR is not well established, nor is it clear which TTR should prompt action.

OBJECTIVES

To investigate the predictive performance of a TTR and identify a threshold below which no recovery of TTR should be expected.

PATIENTS/METHODS

From 18 031 patients who used acenocoumarol in a first-line anticoagulation clinic, a TTR was calculated over multiple periods of 90, 180, and 365 days each. We assessed the correlation between baseline and later TTR and the separation between groups by quintile of baseline TTR. We describe the proportion of patients who obtain a TTR≥ 70% conditional on baseline TTR.

RESULTS

The correlation between baseline and later TTR was 0.25 (95% confidence interval [CI], 0.24-0.26), 0.27 (95% CI, 0.26-0.28) and 0.34 (95% CI, 0.32-0.35) for analyses over 90, 180, and 365 days. Corresponding c statistics for discrimination by baseline group were 0.60, 0.61, and 0.63. The probability to obtain a TTR ≥70% increased with baseline TTR: from 42% with a baseline TTR of 50%-65% when TTR was 100% (TTR calculated over 180 days).

CONCLUSIONS

We conclude that a current TTR hardly predicts a future TTR. Physicians and patients should deliberate together which probabilities to accept, take measures to improve TTR, and consider potential alternatives.

Health Economic Analysis of Rivaroxaban and Warfarin for Venous Thromboembolism Management in Chinese Patients

PURPOSE

Rivaroxaban, a direct oral anticoagulant, has demonstrated non-inferiority to warfarin for venous thromboembolism (VTE) treatment in clinical trials. This study aimed to analyze the direct medical costs for VTE management with rivaroxaban versus warfarin in Hong Kong Chinese patients.

METHODS

In this retrospective observational study, VTE patients admitted to the Princess Margaret Hospital from March 2012 to February 2017 who were initiated and discharged with either rivaroxaban or warfarin were included. Patient demographic and clinical data, and healthcare resource utilization for VTE management were collected for the VTE index admission and 1-year post-discharge period.

RESULTS

A total of 181 patients (90 in the rivaroxaban group; 91 in the warfarin group) were included. The mean (± SD) length of stay (LOS) was 4.8 ± 2.7 days and 8.0 ± 3.0 days in the rivaroxaban and warfarin groups, respectively (p > 0.001). The total cost for VTE index admission in the rivaroxaban group was significantly lower than that of the warfarin group (USD 5473 ± 1914 versus USD 3457 ± 1796; p < 0.001) (USD 1 = HKD 7.8). Recurrent VTE and bleeding rates in 1-year post-discharge period were not significantly different between the two groups. The direct total cost of the rivaroxaban group (USD 1271 ± 767) was significantly lower than that of the warfarin group (USD 1739 ± 1045) in 1-year post-discharge period (p < 0.001).

CONCLUSIONS

Total direct cost and LOS for VTE admission and total cost in 1-year post-discharge period were significantly lower in patients initiated and discharged with rivaroxaban than those of warfarin.

Identification of environmental and genetic factors that influence warfarin time in therapeutic range

Warfarin is an oral anticoagulant prescribed to prevent and treat thromboembolic disorders. It has a narrow therapeutic window and must have its effect controlled. Prothrombin test, expressed in INR value, is used for dose management. Time in therapeutic range (TTR) is an important outcome of quality control of anticoagulation therapy and is influenced by several factors. The aim of this study was to identify genetic, demographic, and clinical factors that can potentially influence TTR. In total,422 patients using warfarin were investigated. Glibenclamide co-medication and presence of CYP2C9*2 and/or *3 alleles were associated with higher TTR, while amiodarone, acetaminophen and verapamil co-medication were associated with lower TTR. Our data suggest that TTR is influenced by co-medication and genetic factors. Thus, individuals in use of glibenclamide may need a more careful monitoring and genetic testing (CYP2C9*2 and/or *3 alleles) may improve the anticoagulation management. In addition, in order to reach and maintain the INR in the target for a longer period, it is better to discuss dose adjustment in office instead of by telephone assessment. Other studies are needed to confirm these results and to find more variables that could contribute to this important parameter.

Evaluation of a program of pharmaceutical counseling for French patients on oral anticoagulant therapy

Background Oral anticoagulants are widely used for treatment and prevention of thromboembolic diseases. We set up a pharmaceutical counseling program for both direct oral anticoagulant and vitamin K antagonist drugs in our hospital in 2015. Objective Evaluate patient satisfaction and the evolution of their knowledge throughout the pharmaceutical counseling program on anticoagulants and identify knowledge variability factors. Setting Cardiology Inpatient Unit from the University Antoine Béclère Hospital, France. Methods Evaluation was based on data collection of patients surveyed between 2015 and 2018. Inpatients in the cardiology department on oral anticoagulants were eligible. The learning process was designed to enhance patient knowledge and understanding based on 10 cognitive or self-management skills, relating to the optimization of oral anticoagulant therapy management. It consisted in 2 face-to-face interviews during hospitalization and 2 additional phone interviews one and six months after discharge. The median patient score was evaluated at each step of the process as well as the mean score for each item from the global population. A sub-analysis was run on the less well-acquired skills in order to identify risk factors for limited knowledge. The association between those factors and the level of knowledge (score ≥ 7 or < 7) was assessed using Chi square test followed by multivariate analysis. Main outcome measure Patient knowledge of anticoagulation therapy depending on specific factors. Results Of the 880 patients eligible for pharmaceutical counseling, 319 entered the process and 102 completed it. Median knowledge scores were 8/10 and 9/10 after the first and the final interviews respectively with a significant improvement (p = 0.0003). The least well-acquired items at each step were surveillance and under-dosing management. The sub-analysis showed the use of vitamin K antagonist to be linked to an enhanced understanding related to treatment surveillance (p = 0.029). Patients suffering from atrial fibrillation were found to have a worse understanding of under-dosing management (p = 0.013). Finally, patients evaluated the process as helpful and suitable for their conditions. Conclusion Pharmaceutical counseling is appropriate for patients, improving and maintaining knowledge of oral anticoagulants. Our evaluation highlights the need to focus on patient-specific profiles to reach a satisfactory level of knowledge.

Risk factors for medication non-adherence among atrial fibrillation patients

Background

Atrial fibrillation (AF) patients are routinely prescribed medications to prevent and treat complications, including those from common co-occurring comorbidities. However, adherence to such medications may be suboptimal. Therefore, we sought to identify risk factors for general medication non-adherence in a population of patients with atrial fibrillation.

Methods

Data were collected from a large, ethnically-diverse cohort of Kaiser Permanente Northern and Southern California adult members with incident diagnosed AF between January 1, 2006 and June 30, 2009. Self-reported questionnaires were completed between May 1, 2010 and September 30, 2010, assessing patient socio-demographics, health behaviors, health status, medical history and medication adherence. Medication adherence was assessed using a previously validated 3-item questionnaire. Medication non-adherence was defined as either taking medication(s) as the doctor prescribed 75% of the time or less, or forgetting or choosing to skip one or more medication(s) once per week or more. Electronic health records were used to obtain additional data on medical history. Multivariable logistic regression analyses examined the associations between patient characteristics and self-reported general medication adherence among patients with complete questionnaire data.

Results

Among 12,159 patients with complete questionnaire data, 6.3% (n = 771) reported medication non-adherence. Minority race/ethnicity versus non-Hispanic white, not married/with partner versus married/with partner, physical inactivity versus physically active, alcohol use versus no alcohol use, any days of self-reported poor physical health, mental health and/or sleep quality in the past 30 days versus 0 days, memory decline versus no memory decline, inadequate versus adequate health literacy, low-dose aspirin use versus no low-dose aspirin use, and diabetes mellitus were associated with higher adjusted odds of non-adherence, whereas, ages 65–84 years versus < 65 years of age, a Charlson Comorbidity Index score ≥ 3 versus 0, and hypertension were associated with lower adjusted odds of non-adherence.

Conclusions

Several potentially preventable and/or modifiable risk factors related to medication non-adherence and a few non-modifiable risk factors were identified. These risk factors should be considered when assessing medication adherence among patients diagnosed with AF.

The Quality of Anticoagulation Therapy among Warfarin-Treated Patients with Atrial Fibrillation in a Primary Health Care Setting

Background and objectives: Long-term therapy with oral anticoagulants is recommended for stroke prevention in patients with atrial fibrillation (AF). This study evaluated the quality of anticoagulation therapy among warfarin-treated AF patients in selected primary health care centres in Lithuania. Materials and Methods: This was a retrospective study conducted in nine primary health care centres in Lithuania. Existing medical records of randomly selected adult patients with AF who were treated with warfarin for at least 12 months were reviewed and analysed. Physicians' decisions to adjust warfarin dose were considered as consistent with the approved warfarin posology if warfarin dose was increased in case of international normalized ratio (INR) <2.0, decreased in case of INR >3.0 or unchanged in case of INR within 2.0 to 3.0. Results: The study population included 406 patients. The mean duration of treatment with warfarin was 5.4 years. The median number of INR measurements per patient per year was 8.0. More than half (57.3%) of available INR values were outside the target range, with 13.6% INR values being above 3.0 and 43.7% INR values-below 2.0. The median time in therapeutic range (TTR) was 40.0%; only 20% of patients had TTR of ≥65%. In about 40% of the cases with INR values outside the target range, no dose corrections were implemented. About 27% of decisions on warfarin dose adjustment were not consistent with the recommended warfarin posology. The median number of INR measurements was lower among patients living in urban areas, while the median TTR was significantly higher in urban patients than in rural patients. In the multivariate regression model, gender, HAS-BLED score and warfarin treatment duration were associated with a TTR of ≥65%. Conclusions: Anticoagulation control is suboptimal in routine clinical practice with a median TTR of 40%. Our findings suggest that there might be a room for improvement of anticoagulation control in primary care.

International normalised ratio monitoring in the community populations of the Auckland and Northland regions of New Zealand: time in therapeutic range and frequency of testing

BACKGROUND

Warfarin remains a commonly used anticoagulant for the treatment and prevention of thrombosis. To balance the risks and benefits of therapy, monitoring of the international normalised ratio (INR) is necessary. Patients derive most benefit from warfarin when they spend ≥65% of time in the therapeutic range (INR 2-3). We performed an analysis of INR monitoring for the Auckland and Northland regions of New Zealand in order to estimate anticoagulation control and appropriateness of testing at the population level.

METHODS

INR test results and patient demographics (age and sex) were extracted from the laboratory information system of Labtests and Northland Pathology Laboratories for the period of 1 January 2016 to 27 July 2016.

RESULTS

We included 126 184 INR results from 10 922 patients. The median age of patients represented was 74 years and 57% were male. The overall mean time in therapeutic range was 63%, with a mean interval between INR tests of 14 days.

CONCLUSION

Our results indicate that anticoagulant control in our communities could be improved, and that inappropriately frequent INR testing should be redressed. Appropriate interventions could lead to net clinical benefits and reduce resource misallocation.

Clinically relevant bleeding in cancer patients treated for venous thromboembolism from the CATCH study

Essentials Cancer patients receiving anticoagulants for venous thromboembolism have an elevated bleeding risk. This secondary analysis of CATCH assessed characteristics of clinically relevant bleeding (CRB). CRB occurs in 15% of cancer patients with thrombosis using therapeutic doses of anticoagulation. After multivariate analysis, risk factors for CRB were age >75 years and intracranial malignancy.

SUMMARY

Background Cancer patients with acute venous thromboembolism (VTE) receiving anticoagulant treatment have an increased bleeding risk. Objectives We performed a prespecified secondary analysis of the randomized, open-label, Phase III CATCH trial (NCT01130025) to assess the rate and sites of and the risk factors for clinically relevant bleeding (CRB). Patients/Methods Patients with active cancer and acute, symptomatic VTE received either tinzaparin 175 IU kg-1 once daily or warfarin (target International Normalized Ratio [INR] of 2.0-3.0) for 6 months. Fisher's exact test was used to screen prespecified clinical risk factors; those identified as being significantly associated with an increased risk of CRB then underwent competing risk regression analysis of time to first CRB. Results Among 900 randomized patients, 138 (15.3%) had 180 CRB events. CRB occurred in 60 patients (81 events) in the tinzaparin group and in 78 patients (99 events) in the warfarin group (hazard ratio [HR] 0.64; 95% confidence interval [CI] 0.45-0.89). Common bleeding sites were gastrointestinal (36.7%; n = 66), genitourinary (22.8%; n = 41), and nasal (10.0%; n = 18). In multivariate analysis, the risk of CRB increased with age > 75 years (HR 1.83, 95% CI 1.14-2.94) and intracranial malignancy (HR 1.97, 95% CI 1.07-3.62). In the warfarin group, 40.4% of CRB events occurred in patients with with an INR of < 3.0. A lower time in therapeutic range was associated with a higher risk of CRB. Conclusions CRB is a frequent complication in cancer patients with VTE during anticoagulant treatment, and is associated with age > 75 years and intracranial malignancy.

Quality of Anticoagulation With Warfarin at a Tertiary Hospital in Botswana

Warfarin treatment requires regular and proper monitoring to avoid overanticoagulation and at the same time to prevent thromboembolic complications. This study assessed the quality of warfarin anticoagulation at Princess Marina Hospital in Botswana. This cross-sectional study consecutively enrolled patients who were on warfarin for at least 3 months in the outpatient medical clinic. The level of anticoagulation was determined by the time in therapeutic range (TTR) using the Rosendaal method that calculates the percentage of days when the international normalized ratio is in the therapeutic range (2.0-3.0). Poor anticoagulation control was defined as an estimated TTR <65%. We performed univariate and multivariate logistic regression to assess predictors of poor anticoagulation control. Of total, 410 (68.8% women) patients whose median age was 46 (interquartile range [IQR], 35-58) years were enrolled. Indications for warfarin included mechanical heart valves, 185 (45.1%); deep vein thrombosis, 114 (26.8%); and atrial fibrillation, 68 (17.8%). Of the 2004 tests (an average of 4.9 tests per patient) assessed, only 20% of the tests were within the therapeutic range. The median TTR was 30.8% (IQR, 15.2-52.7). Most (85.1%) patients had poor anticoagulation control. Cigarette smoking and pulmonary hypertension perfectly predicted poor anticoagulation. Hypertension was a predictor of poor anticoagulation control (adjusted odds ratio = 2.24; 95% confidence interval: 1.02-4.94). The quality of anticoagulant therapy with warfarin in Botswana patients is poor. The evidence calls for efforts to improve the level of anticoagulation control among patients on warfarin in Botswana.

Clinical usefulness of the SAMe-TT2R2 score: A systematic review and simulation meta-analysis

Background

Vitamin K antagonist (VKA) therapy is safer and more effective when patients have a high time within the therapeutic range and low international normalised ratio variability. The SAMe-TT₂R₂ score aims to identify those at risk for poor VKA control.

Objectives

To evaluate the predictive value and clinical usefulness of the SAMe-TT₂R₂ score to identify those at risk for poor VKA control.

Methods

We performed a systematic review in MEDLINE and Embase for original research papers assessing the SAMe-TT₂R₂’s relation to poor TTR. We performed a meta-analysis where scores ≥ 2 and ≥ 3 predicting TTR < 70%. When studies evaluated other cutoffs for TTR or SAMe-TT₂R₂, they were harmonised by multiple simulations with patient characteristics from the individual studies, if the data were available.

Results

16 studies were identified and used in the meta-analysis: 4 and 2 times directly, 8 and 8 times harmonised for scores ≥ 2 and ≥ 3, respectively (not all studies provided information about both cutoffs). The sensitivities and specificities were too heterogeneous to pool. The positive likelihood ratios were 1.25 (1.14-1.38) for a score ≥ 2, and 1.24 (1.09-1.40) for a score ≥ 3; the negative ones were 0.87 (0.82-0.93) and 0.96 (0.91-1.02), respectively. This shows that the post-test probabilities hardly differ from the prior probability (prevalence).

Conclusion

The SAMe-TT₂R₂ score does predict low TTR, but the effect is small. Its effect on individual patients is too limited to be clinically useful.

Quality of anticoagulation control and hemorrhage risk among African American and European American warfarin users

OBJECTIVE

We evaluated whether percent time in target range (PTTR), risk of over-anticoagulation [international normalized ratio (INR)>4], and risk of hemorrhage differ by race. As PTTR is a strong predictor of hemorrhage risk, we also determined the influence of PTTR on the risk of hemorrhage by race.

PARTICIPANTS AND METHODS

Among 1326 warfarin users, PTTR was calculated as the percentage of interpolated INR values within the target range of 2.0-3.0. PTTR was also categorized as poor (PTTR<60%), good (60≤PTTR<70%), or excellent (PTTR≥70%) anticoagulation control. Over-anticoagulation was defined as INR more than 4 and major hemorrhages included serious, life-threatening, and fatal bleeding episodes. Logistic regression and survival analyses were carried out to evaluate the association of race with PTTR (≥60 vs. <60) and major hemorrhages, respectively.

RESULTS

Compared with African Americans, European Americans had higher PTTR (57.6 vs. 49.1%; P<0.0001) and were more likely to attain 60≤PTTR<70% (22.9 vs. 13.1%; P<0.001) or PTTR of at least 70% (26.9 vs. 18.2%; P=0.001). Older (>65 years) patients without venous thromboembolism indication and chronic kidney disease were more likely to attain PTTR of at least 60%. After accounting for clinical and genetic factors, and PTTR, African Americans had a higher risk of hemorrhage [hazard ratio (HR)=1.58; 95% confidence interval (CI): 1.04-2.41; P=0.034]. Patients with 60≤PTTR<70% (HR=0.62; 95% CI: 0.38-1.02; P=0.058) and PTTR of at least 70% (HR=0.27; 95% CI: 0.15-0.49; P<0.001) had a lower risk of hemorrhage compared with those with PTTR less than 60%.

CONCLUSION

Despite the provision of warfarin management through anticoagulation clinics, African Americans achieve a lower overall PTTR and have a significantly higher risk of hemorrhage. Personalized medicine interventions tailored to African American warfarin users need to be developed.

Quality of Anticoagulation With Warfarin at a Tertiary Hospital in Botswana

Warfarin treatment requires regular and proper monitoring to avoid overanticoagulation and at the same time to prevent thromboembolic complications. This study assessed the quality of warfarin anticoagulation at Princess Marina Hospital in Botswana. This cross-sectional study consecutively enrolled patients who were on warfarin for at least 3 months in the outpatient medical clinic. The level of anticoagulation was determined by the time in therapeutic range (TTR) using the Rosendaal method that calculates the percentage of days when the international normalized ratio is in the therapeutic range (2.0-3.0). Poor anticoagulation control was defined as an estimated TTR <65%. We performed univariate and multivariate logistic regression to assess predictors of poor anticoagulation control. Of total, 410 (68.8% women) patients whose median age was 46 (interquartile range [IQR], 35-58) years were enrolled. Indications for warfarin included mechanical heart valves, 185 (45.1%); deep vein thrombosis, 114 (26.8%); and atrial fibrillation, 68 (17.8%). Of the 2004 tests (an average of 4.9 tests per patient) assessed, only 20% of the tests were within the therapeutic range. The median TTR was 30.8% (IQR, 15.2-52.7). Most (85.1%) patients had poor anticoagulation control. Cigarette smoking and pulmonary hypertension perfectly predicted poor anticoagulation. Hypertension was a predictor of poor anticoagulation control (adjusted odds ratio = 2.24; 95% confidence interval: 1.02-4.94). The quality of anticoagulant therapy with warfarin in Botswana patients is poor. The evidence calls for efforts to improve the level of anticoagulation control among patients on warfarin in Botswana.

Vitamin K antagonist therapy: changes in the treated populations and in management results in Italian anticoagulation clinics compared with those recorded 20 years ago

Vitamin K antagonists (VKA) are the most widely used anticoagulants in the world. An appropriate management of treated patients is crucial for their efficacy and safety. The prospective, observational, multicenter, inception-cohort FCSA-START Register, a branch of START Register (NCT02219984) included VKA-treated patients managed by centers of Italian Federation of anticoagulation clinics (AC). Baseline patient characteristics and data during treatment were analyzed and compared with those of ISCOAT study, performed by the Federation and published in 1996/7. 5707 naïve patients [53% males, mean age 73.0 years (28.1% >80 years)], 61.6% treated for atrial fibrillation (AF), and 28.0% for venous thromboembolism were included. During the 8906 patient-years (pt-yrs) of observation, 123 patients had major bleeding (MB) (1.38% pt-yrs; fatal: 0.11% pt-yrs), while non-major clinically relevant bleeds were 144 (1.62% pt-yrs). Bleeding was more frequent in elderly (≥70 years; p = 0.04), and during initial 3-month therapy (p = 0.02). Bleeding rate was 2.5% pt-yrs for temporally related INR results <3.0, increasing to 12.5% for INR ≥ 4.5. Thrombotic events were 47 (0.53% pt-yrs; 4 fatal 0.04% pt-yrs). Compared with ISCOAT-1996/7 results, patients older than 80 y are increased from 8 to 28% (p < 0.01), and those treated for AF are increased from 17 to 61%. The quality of anticoagulation control and incidence of MB are not different. However, thrombotic complications fell drastically from 3.5 to 0.53% pt-yrs (p < 0.01), with lower mortality (p = 0.01). VKA-treated patients monitored in Italian AC have good clinical results, with low bleeding and thrombotic complications rates. Important changes in the treated population and improvement in thrombotic complications are detected compared with the ISCOAT-1996/7 study.

Prediction Score for Anticoagulation Control Quality Among Older Adults

BACKGROUND

Time in the therapeutic range (TTR) is associated with the effectiveness and safety of vitamin K antagonist (VKA) therapy. To optimize prescribing of VKA, we aimed to develop and validate a prediction model for TTR in older adults taking VKA for nonvalvular atrial fibrillation and venous thromboembolism.

METHODS AND RESULTS

The study cohort comprised patients aged ≥65 years who were taking VKA for atrial fibrillation or venous thromboembolism and who were identified in the 2 US electronic health record databases linked with Medicare claims data from 2007 through 2014. With the predictors identified from a systematic review and clinical knowledge, we built a prediction model for TTR, using one electronic health record system as the training set and the other as the validation set. We compared the performance of the new models to that of a published prediction score for TTR, SAMe-TT2R2. Based on 1663 patients in the training set and 1181 in the validation set, our optimized score included 42 variables and the simplified model included 7 variables, abbreviated as PROSPER (Pneumonia, Renal dysfunction, Oozing blood [prior bleeding], Staying in hospital ≥7 days, Pain medication use, no Enhanced [structured] anticoagulation services, Rx for antibiotics). The PROSPER score outperformed SAMe-TT2R2 when predicting both TTR ≥70% (area under the receiver operating characteristic curve 0.67 versus 0.55) and the thromboembolic and bleeding outcomes (area under the receiver operating characteristic curve 0.62 versus 0.52).

CONCLUSIONS

Our geriatric TTR score can be used as a clinical decision aid to select appropriate candidates to receive VKA therapy and as a research tool to address confounding and treatment effect heterogeneity by anticoagulation quality.

SAMe-TT2R2 predicts quality of anticoagulation in patients with acute venous thromboembolism: The MAQI2 experience

A high SAMe-TT₂R₂ score predicted poor warfarin control and adverse events among atrial fibrillation patients. However, the SAMe-TT₂R₂ score has not been well validated in venous thromboembolism (VTE) patients. A cohort of 1943 warfarin-treated patients with acute VTE was analyzed to correlate the SAMe-TT₂R₂ score with time in therapeutic range (TTR) and clinical adverse events. A TTR <60% was more frequent among patients with a high (>2) versus low (0-1) SAMe-TT₂R₂ score (63.4% vs 52.3%, p<0.0001). A high SAMe-TT₂R₂ score (>2) correlated with increased overall adverse events (7.9 vs 4.5 overall adverse events/100 patient years, p=0.002), driven primarily by increased recurrent VTE rates (4.2 vs 1.5 recurrent VTE/100 patient years, p=0.0003). The SAMe-TT₂R₂ score had a modest predictive ability for international normalized ratio (INR) quality and adverse clinical events among warfarin-treated VTE patients. The utility of the SAMe-TT₂R₂ score to guide clinical decision-making remains to be investigated.

Early real-world evidence of persistence on oral anticoagulants for stroke prevention in non-valvular atrial fibrillation: a cohort study in UK primary care

OBJECTIVES

To examine the characteristics and persistence in patients newly initiated with oral anticoagulants (OACs) for stroke prevention in non-valvular atrial fibrillation (NVAF).

DESIGN

Cohort study in Clinical Practice Research Datalink.

SETTING

UK primary care.

PARTICIPANTS

15 242 patients with NVAF newly prescribed apixaban, rivaroxaban, dabigatran or vitamin K antagonists (VKAs) between 1 December 2012 and 31 October 2014. 13 089 patients were OAC naïve.

OUTCOME MEASURES

Patient characteristics and risk of non-persistence compared to apixaban using Cox regression models over the entire follow-up and using a time-partitioned approach to handle non-proportional hazards.

RESULTS

Among the OAC naïve patients, VKAs were most common (78.1%, n=10 218), followed by rivaroxaban (12.1%, n=1589), dabigatran (5.7%, n=741) and apixaban (4.1%, n=541). High baseline stroke risk (CHA₂DS₂VASc ≥2) ranged from 80.2% (dabigatran) to 88.4% (apixaban and rivaroxaban). History of stroke and bleeding was the highest among apixaban (23.7% and 31.6%) and lowest among VKA patients (15.9% and 27.5%). Across the entire follow-up period, adjusting for differences in characteristics, there was no evidence of a difference in non-persistence between VKA and apixaban (HR 0.92 (95% CI 0.68 to 1.23)). Non-persistence was higher with dabigatran (HR 1.67 (1.20 to 2.32)) and rivaroxaban (HR 1.41 (1.02 to 1.93)) than apixaban. Using the partitioned approach, non-persistence was lower with VKA (HR 0.33 (0.22 to 0.48)), and higher with dabigatran (HR 1.65 (1.08 to 2.52)) compared to apixaban in the first 2 months of follow-up. After 2 months, non-persistence was higher with VKA (HR 1.70 (1.08 to 2.66)) and dabigatran (HR 2.10 (1.30 to 3.41)). Pooling OAC naïve and experienced patients, non-persistence was also higher with rivaroxaban compared to apixaban after 2 months of follow-up (HR 1.69 (1.19 to 2.39)).

CONCLUSIONS

Observed differential prescribing of OACs can result in channelling bias in comparative effectiveness research. Persistence patterns changed over follow-up time, but there are indications of improved persistence rates with apixaban over other OACs in the UK. A larger study with longer follow-up is needed to corroborate findings. This study is registered on ClinicalTrials.gov (NCT02488421).

Anticoagulation Control in Swiss Primary Care: Time in Therapeutic Range Percentages Exceed Benchmarks of Phase III Trials

BACKGROUND

In randomized controlled trials, non-vitamin K antagonist oral anticoagulants (NOACs) demonstrated noninferiority to vitamin K antagonists (VKAs) in patients who spent limited time in therapeutic range (TTR). In real-life patients, TTR is known to vary significantly across countries and health-care settings.

OBJECTIVE

We aim to evaluate the quality of VKA treatment in Swiss primary care (PC) by comparing patients' median TTR to levels achieved in the phase III NOAC trials RE-LY, ROCKET-AF, ARISTOTLE, and ENGAGE-AF-TIMI 48. Patient characteristics affecting TTR control shall be estimated.

METHODS

This is a retrospective longitudinal study in Swiss PC patients receiving VKA for ≥6 months. We identified patients from the PC research database FIRE (Family medicine International Classification of Primary Care Research using Electronic medical records) and calculated TTR according to Rosendaal formula. Comparative data from NOAC trials were retrieved from medical literature. Linear regression models were used to assess predictors of TTR.

RESULTS

Primary care encounters of 215 patients were analyzed. Like in the NOAC trials, median observation period was 2.2 years, but patients were older (67.9% vs 38% ≥75 years) and differed in terms of concomitant diseases and drugs. Median TTR was 75% (65% in the NOAC trials). Female sex was independently associated with a lower TTR and significantly modified by increasing age.

CONCLUSION

Practitioners should consider that patients in NOAC trials are only partly representative of PC patients, particularly in terms of TTR control. Only a minority of the observed patients would require a therapy switch to NOACs due to inadequate TTR. Further research is needed in order to identify specific features of care management that are associated with these outcomes.