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

Anticoagulation Management in Patients Receiving Warfarin at Private Cardiac Centers in Addis Ababa, Ethiopia

Introduction

Anticoagulants are the cornerstone therapy for thromboembolism prevention and treatment. Warfarin is the frequently prescribed drug and remains the oral anticoagulant of choice in low- and middle-income countries, including Ethiopia. It is a narrow therapeutic index drug that needs high-quality anticoagulation monitoring with frequent international normalization ratio (INR) testing.

Objective

The study aimed to assess anticoagulation management with warfarin among adult outpatients at two selected private cardiac centers in Addis Ababa, Ethiopia.

Methods

A hospital-based retrospective study design that enrolled 374 patients receiving warfarin was employed at two private cardiac centres in Addis Ababa, Ethiopia. The time in the therapeutic range (TTR) was calculated using the Rosendaal method. The data were analyzed using Statistical Package for Social Science version 25.

Results

The mean age of the patients was 57 years, and 218 (58.3%) participants were females. Out of 3384 INR tests, 1562 (46.5%) were within the therapeutic range and the mean percentage of TTR was 47.24%. Only 25.67% of the patients spent their TTR ≥ 65%. The present study revealed that dose adjustments were required 1764 times. In non-therapeutic INR values of 1764 that required warfarin dose adjustment, 59.7% of the doses were adjusted. About 262 (70.1%) of co-prescribed medications had interaction with warfarin. Sixty-four patients (17.11%) experienced bleeding events.

Conclusion

Anticoagulation management with warfarin was suboptimal in private cardiac Addis Ababa, Ethiopia, private cardiac centers. Warfarin adjustment practice for nontherapeutic INR values was not minimal, and many patients encountered bleeding during their course of therapy.

Control of Therapeutic Levels of Anticoagulation and Associated Factors: A Prospective Cohort Study

Maintaining therapeutic levels of anticoagulation is essential to avoid health complications in people who take vitamin K antagonists. This study aimed to analyze the influence of people's characteristics and the presence of changes in their lives in the control of therapeutic levels of anticoagulation. A longitudinal multicenter study with a 1-year follow-up of a cohort of 199 people receiving anticoagulant therapy was performed. The effect of biological, clinical, social, lifestyle, and changes in life on the international normalized ratio (INR) was analyzed. During the follow-up, 46.7% of participants presented good INR control. At baseline, a diagnosis of atrial fibrillation (P = .00), the lack of comorbidities (P = .03), absence of depression (P = .04), and not following a pharmacological treatment with hypoglycemia drugs (P = .01) were associated with good INR control. During the follow-up, the variable of making changes to the usual diet was associated with poor INR control (P = .05). In the binary multiple regression model, factors associated with poor control were taking hypoglycemia drugs (P = .02) and the presence of depression (P = .04), and only the diagnosis of atrial fibrillation was associated with good control (P = .03). People with a diagnosis of atrial fibrillation had good INR control. Having comorbidities, suffering depression, taking hypoglycemia drugs, and making changes to the diet have a negative effect on INR control.

Anticoagulation control, outcomes, and associated factors in long-term-care patients receiving warfarin in Africa: a systematic review

Background

Oral anticoagulation therapy with warfarin requires frequent monitoring level of anticoagulation by the international normalized ratio (INR). In Africa, studies that explore anticoagulation control, treatment outcomes, and associated factors are reported in various ways in long-term patients receiving warfarin therapy to generate concrete scientific evidence.

Methods

The literature search was conducted in PubMed, Cochrane Library, African Journal of Online databases, Google Scholar, and Google. An advanced search strategy was computed to retrieve relevant studies related to anticoagulation control and outcomes. Duplication, title and abstract screening, and full-text assessment were conducted in Covidence software. Study quality was assessed using the Joanna Briggs Institute Critical appraisal quality assessment tool. The systematic review is registered in PROSPERO (CRD42021260772) and performed based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guideline.

Results

Out of 298 identified articles, 18 articles were eligible for the final review and analysis. The mean of 39.4 ± 8.4% time in therapeutic range (TTR) (29.4 to 57.3%), 36.7 ± 11.5% TTR (range 25.2–49.7%) and 46% TTR (43.5–48.5%) was computed from studies that determined TTR by Rosendaal, direct and cross-section-of-the-files methods, respectively. In this review, the lowest percentage of TTR was 13.7%, while the highest was 57.3%. The highest percentage of patients (32.25%) who had TTR ≥ 65% was reported in Tunisia, but the lowest percentages were in Namibia (10%, TTR ≥ 65%) and Kenya (10.4%, TTR ≥ 70%). Most of the included studies (11 out of 18) used Rosendaal’s method while the direct method was employed by three studies. Generally, 10.4–32.3% of study participants achieved desired optimal anticoagulation level. Regarding secondary outcomes, 1.6–7.5% and 0.006–59% of patients experienced thromboembolic complications and bleeding events, respectively. Having chronic comorbidities, taking more than two drugs, and presence of medications that potentially interact with warfarin, and patient-related factors (patients aged < 50 years old, female gender, lower education level, smoking history) were the frequently reported predictors of poor anticoagulation therapy.

Conclusions

Oral anticoagulation control was suboptimal in patients taking warfarin as evidenced by low TTR in Africa. Therefore, there is an urgent need for further improving oral anticoagulation management services.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12959-022-00416-9.

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.

Anticoagulation Control, Outcomes, and Associated Factors in Patients with Atrial Fibrillation Receiving Warfarin at Tertiary Care Hospital in Ethiopia

Anticoagulation is the cornerstone in the prevention of stroke in atrial fibrillation. This study aimed at assessing the anticoagulation control and outcome and predictive factors in atrial fibrillation patients on warfarin therapy. A retrospective chart review was used to evaluate patients with atrial fibrillation who were on warfarin during two years follow up at the anticoagulation clinic of the hospital. The time in therapeutic range (TTR) was calculated using Rosendaal's method. Data were analyzed using SPSS software version 25. Univariable and multivariable analyses were computed to determine factors affecting TTR and bleeding events. We included 300 patients in this study. The mean percentage TTR was 42.03 ± 18.75. Only 38 (12.67%) patients achieved a TTR of above 65%. The average international normalized ratio (INR) testing frequency was 35 days (16.3-67.2 days). Taking 1 or 2 drugs along with warfarin was found to be better in achieving good TTR as compared to taking more than two drugs (p = .014). Having heart failure was associated with a 2.45 times odds of poor anticoagulation control (TTR< 65%) (p = .047). Male study participants were 2.53 times more likely of developing bleeding events than females (p = .009). Bleeding events were observed in 62 (20.67%) patients. Study participants, who didn't have Diabetic Mellitus and those not receiving aspirin were at lower odds developing bleeding events (AOR = .196; C.I. = .060-.638; p−.007 and AOR = .099; CI. = .024-.416; p−.02), respectively. In summary, the time spent in the therapeutic range was minimal in this population of patients with AF on warfarin managed at a hospital run anticoagulation clinic in Ethiopia. Moreover, the number of co-prescribed medications, and having heart failure were associated with poor TTR. Bleeding events were high and affected by male sex, having DM comorbidity, and using aspirin.

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.

Required warfarin dose and time in therapeutic range in patients with diagnosed Nonalcoholic Fatty Liver Disease (NAFLD) or Nonalcoholic Steatohepatitis (NASH)

Warfarin has been widely used to treat thromboembolism. The effect of nonalcoholic fatty liver disease (NAFLD) or nonalcoholic steatohepatitis (NASH), on warfarin dosing remains unknown. This study aims to examine the effects of NAFLD/NASH on the average daily dose (ADD) of warfarin and the time in therapeutic range (TTR). This is a retrospective study utilizing an administrative data. We included patients with at least 2 months of warfarin dispensing and two subsequent consecutive INR measures. The ADD of warfarin to achieve therapeutic range INR levels, and TTR were compared between patients with and without NAFLD/NASH in four subgroups of patients accounting for the presence of obesity and diabetes. Generalized linear models (GLM) with Propensity score (PS) fine stratification were applied to evaluate the relative differences (RD) of warfarin ADD and TTR (>60%) in four subgroups. A total of 430 NAFLD/NASH patients and 38,887 patients without NAFLD/NASH were included. The ADD and TTR, were not significant in the overall cohort between those with and without NAFLD/NASH. However, GLM results in patients without diabetes or obesity (N = 26,685) showed a significantly lower warfarin ADD (RD: -0.38; 95%CI: -0.74–-0.02) and shorter TTR (OR: 0.71; 95%CI: 0.52–0.97) in patients diagnosed with NAFLD/NASH. The effects of NAFLD/NASH on warfarin dose or TTR were observed in patients without obesity and diabetes. Obesity and diabetes appear to be significant modifiers for the effects of NAFLD/NASH on warfarin dose and TTR.

The efficacy and safety of direct oral anticoagulants in noncirrhotic portal vein thrombosis

Guidelines currently favor vitamin K antagonists or low-molecular-weight heparins for treatment of noncirrhotic portal vein thrombosis (ncPVT). Use of direct oral anticoagulants (DOACs) in PVT has been met with concern because of the lack of data. We conducted a retrospective study to investigate the efficacy and safety of DOACs for the treatment of ncPVT, and to compare them with standard therapies: 330 patients with ncPVT, followed-up for a mean 41.6 months, received warfarin (n = 108), enoxaparin (n = 70), rivaroxaban (n = 65), apixaban (n = 20), dabigatran (n = 8), fondaparinux (n = 2), or no anticoagulation (n = 57). The primary outcome was complete radiographic resolution (CRR) of PVT. Secondary outcomes included recanalization of occlusive PVT, cavernous transformation of the PV, development of chronic portal hypertensive symptoms (cPHS), and major bleeding. DOACs were associated with the highest CRR rates (dabigatran, 6/8 [75%]; apixaban, 13/20 [65%]; rivaroxaban, 42/65 [65%]). Enoxaparin was associated with a CRR rate similar to that of the DOACs (40/70 = 57%). Warfarin was associated with worse outcomes in this regard (CRR rate, 31% [33/108]; hazard ratio [HR] DOACs:warfarin, 2.91; 95% confidence interval [CI], 1.87-4.52; P < .0001). DOACs were associated with recanalization rates similar to enoxaparin and greater than warfarin (HR DOACs:warfarin, 3.45; 95% CI, 1.93-6.18; P < .0001). DOACs were associated with lower rates of cPHS, although this did not attain significance (DOACs, 8/93 [9%]; enoxaparin, 13/70 [19%]; warfarin, 31/108 [29%]). DOACs were associated with less major bleeding relative to warfarin (HR DOACs:warfarin, 0.20; 95% CI, 0.05-0.86; P = .0307). Patients harboring JAK2V617F, those with no evident predisposing factor for PVT, and those with occlusive thrombus demonstrated worse outcomes. DOACs appear effective and safe for the treatment of ncPVT.

Sex-influence on the time in therapeutic range (TTR) during oral anticoagulation with coumarin derivatives: Systematic review and meta-analysis

AIMS

We sought to investigate the association between sex and oral anticoagulation control employing coumarin derivatives.

METHODS

Electronic sources were MEDLINE, Biblioteca Virtual em Saúde (BVS), The Cumulative Index to Nursing and Allied Health Literature (CINAHL), EMBASE, Cochrane Central and Web of Science. Inclusion criteria were: observational and experimental studies; age ≥18 years; both sexes; treatment with any coumarin derivative for ≥3 months; any indication of long-term use; quality of oral anticoagulation measured by time in therapeutic range (TTR). The meta-analysis was developed with odds ratios (OR) for binary variables and mean differences (MD) for continuous variables, using random-effects models (DerSimonian and Laird) with 95% confidence intervals (CI).

RESULTS

Overall, 22 articles were selected, comprising 16 cohort studies, four cross-sectional studies and two clinical trials. The number of participants ranged from 110 to 104 505 (183 612; women: 45%). The main indication of oral anticoagulation was atrial fibrillation. Most studies reported the use of warfarin. In the meta-analysis, 15 studies were analysed using TTR as a binary variable (OR = 0.87; 95% CI = 0.78, 0.96; z = -2.75; P = .006.; I²  = 67%) and seven studies as a continuous variable (MD = -2.97; 95% CI = -4.80, -1.14; z = -3.19; P = .0014; I²  = 75%). The pooled estimates indicated that women were associated with lower TTR than men.

CONCLUSIONS

Our findings revealed an association between female sex and worse oral anticoagulation control. Further studies are needed with primary design to investigate sex-related factors influencing oral anticoagulation control with coumarin derivatives. Innovative strategies focused on women's health may be useful to improve patient-centred care.

Clinical Impact of the Time in Therapeutic Range on Early Hospital Readmission in Patients with Acute Heart Failure Treated with Oral Anticoagulation in Internal Medicine

Background and objectives: Patients with heart failure (HF) often present with non-valvular atrial fibrillation and require oral anticoagulation with coumarin anticoagulants such as acenocoumarol. The objective of this study was to evaluate the relationship between time in therapeutic range (TTR) and the risk of early readmission. Materials and Methods: A retrospective descriptive study was carried out on hospitalized patients with a diagnosis of HF between 2014 and 2018 who had adverse effects due to oral anticoagulation with acenocoumarol (underdosing, overdosing, or hemorrhage). Clinical, analytical, therapeutic, and prognostic variables were collected. TTR is defined as the duration of time in which the patient’s International Normalized Ratio (INR) values were within a desired range. Early readmission was defined as readmission within 30 days after hospital discharge. Patients were divided into two groups depending on whether or not they had a TTR less than 60% (TTR < 60%) over the 6 months prior to the adverse event. Results: In the cohort of 304 patients, the mean age was 82 years, 59.9% of the patients were female, and 54.6% had a TTR < 60%. Patients with TTR < 60% had a higher HAS-BLED score (4.04 vs. 2.59; p < 0.001) and INR (6 vs. 5.31; p < 0.05) but lower hemoglobin (11.67 vs. 12.22 g/dL; p < 0.05). TTR < 60% was associated with early readmission after multivariate analysis (OR: 2.05 (CI 95%: 1.16–3.61)). They also had a higher percentage of hemorrhagic events and in-hospital mortality but without reaching statistical significance. Conclusions: Patients with HF and adverse events due to acenocoumarol often have poor INR control, which is independently associated with a higher risk of early readmission.

The Natural History, Treatments, and Outcomes of Portal Vein Thrombosis in Patients With Inflammatory Bowel Disease

BACKGROUND

Portal vein thrombosis (PVT) is a poorly described complication of inflammatory bowel disease (IBD). We sought to better characterize presentations, compare treatments, and assess outcomes in IBD-related PVT.

METHODS

We conducted a retrospective investigation of IBD-related PVT at our institution. Multivariable Cox proportional hazards modeling was used to estimate adjusted hazard ratios across treatments.

RESULTS

Sixty-three patients with IBD-related PVT (26 with Crohn disease, 37 with ulcerative colitis) were followed for a median 21 months (interquartile ratio [IQR] = 9-52). Major risk factors included intra-abdominal surgery (60%), IBD flare (33%), and intra-abdominal infection (13%). Primary hematologic thrombophilias were rare and did not impact management. Presentations were generally nonspecific, and diagnosis was incidental. Ninety-two percent of patients (58/63) received anticoagulation (AC), including 23 who received direct oral anticoagulants (DOACs), 22 who received warfarin, and 13 who received enoxaparin. All anticoagulated patients started AC within 3 days of diagnosis. Complete radiographic resolution (CRR) of PVT occurred in 71% of patients. We found that DOACs were associated with higher CRR rates (22/23; 96%) relative to warfarin (12/22; 55%): the hazard ratio of DOACs to warfarin was 4.04 (1.83-8.93; P = 0.0006)). Patients receiving DOACs required shorter courses of AC (median 3.9 months; IQR = 2.7-6.1) than those receiving warfarin (median 8.5 months; IQR = 3.9-NA; P = 0.0190). Incidence of gut ischemia (n = 3), symptomatic portal hypertension (n = 3), major bleeding (n = 4), and death (n = 2) were rare, and no patients receiving DOACs experienced these adverse outcomes.

CONCLUSIONS

We show that early and aggressive use of AC can lead to excellent outcomes in IBD-associated PVT and that DOACs are associated with particularly favorable outcomes in this setting.

Atrial fibrillation care in rural communities: a mixed methods study of physician and patient perspectives

Background

Atrial fibrillation (AF) is a serious heart arrhythmia associated with devastating outcomes such as stroke. Inequitable rural AF care may put patients at risk. Virtually delivered specialty AF care offers a viable option, but stakeholder perceptions of this option within the context of rural AF care is unknown. The study purpose was to obtain patient and primary care physician perspectives of rural AF care and virtually delivered AF care as a potential option.

Methods

Using a mixed methods design, AF patients (n = 101) and physicians (n = 15) from three rural communities participated in focus groups and/or surveys. Focus group data were thematically analyzed, survey data were descriptively analyzed, and data were triangulated.

Results

Findings captured patients’ and physicians’ perceptions of prioritized, needs, concerns and problems in AF management, available/unavailable services, and their ideas about virtual AF care. Patients and physicians identified eclectic problems in managing AF. Overall, patients felt ill informed about managing their AF and their most salient problems related to fatigue, exercise intolerance, weight maintenance, sleep apnea, and worry about stroke and bleeding. Physicians found treating patients with co-morbidities and cognitive decline problematic and balancing risks related to anticoagulation challenging. Patients and physicians identified education as a pressing need, which physicians lacked time and resources to meet. Despite available rural services, access to primary and cardiology care was a recurring challenge, and emergency department (ED) use highly contentious but often the only option for accessing care. Physicians’ managed AF care and varied in the referrals they made, often reserving them for complex situations to avoid patient travel. Patients and providers supported a broad approach to virtual AF care, tailored to an inclusive rural patient demographic.

Conclusions

The study offered valuable physician and patient perspectives on AF care in rural communities including diverse management challenges, gaps in access to primary and specialty services that made ED an often used but contentious option. Findings point to the potential value of virtual care designed to reach patients with AF across the spectrum and geared to local contexts that preserve the vital role of primary care physicians in AF care in their communities.