Effectiveness and Safety of DOACs vs. VKAs in AF Patients With Cancer: Evidence From Randomized Clinical Trials and Observational Studies

Direct Oral Anticoagulants in Chronic Thromboembolic Pulmonary Hypertension: First Meta-Analysis of Prospective Studies

Direct oral anticoagulants (DOACs) are becoming increasingly popular clinically, but their safety and effectiveness profile in patients with chronic thromboembolic pulmonary hypertension (CTEPH) is not well-established. Literature from the PubMed and EMBASE databases was systematically screened up to February 2024 to identify relevant studies on the use of DOACs in CTEPH patients. The bias risk of RCTs was assessed using the Cochrane Risk of Bias Tool 2.0. The quality of observational prospective cohorts was assessed using the Newcastle-Ottawa Scale tool. Data pooled from different studies were analyzed. Results from 4 studies were gathered, including 2 randomized controlled trials and 2 prospective cohorts, with a total of 2038 patients, of which 751 were on DOACs and 1287 were on vitamin K antagonists (VKAs). Similar rates of all-cause mortality (3.33% vs 3.33%, RD = -0.01%, 95% CI [-0.02%, 0.00%], P = .17), VTE recurrence (1.46% vs 2.12%, RD = -0.00%, 95% CI [-0.01%, 0.01%], P = .92) were observed. DOACs were associated with a nonsignificant reduction in bleeding events including major bleeding (2.22% vs 3.71%, RD = -0.01%, 95% CI [-0.04%, 0.01%], P = .30), any bleeding (5.33% vs 9.94%, RD = -0.03%, 95% CI [-0.07%, 0.01%], P = .10), and minor bleeding (4.17% vs 13.3%, RD = -0.06%, 95% CI [-0.23%, 0.10%], P = .45). Data pooled from existing perspective trials suggests the use of DOACs in CTEPH patients as an effective and safe alternative to VKAs.

Current Data and Future Perspectives on Patients with Atrial Fibrillation and Cancer

Atrial fibrillation (AF) is an increasingly recognized comorbidity in patients with cancer. Indeed, cancer patients have a significantly higher incidence of AF than that observed in the general population. A reciprocal relationship between these two diseases has been observed, as much as some assume AF to be a marker for occult cancer screening, especially in older adults. The pathophysiological mechanisms are many and varied, including the underlying pro-inflammatory state, specific treatments (chemo- and radiotherapy), and surgery. The therapeutic management of patients with cancer and AF involves the same rhythm and frequency control strategies as the general population; however, the numerous interactions with chemotherapeutics, which lead to a significant increase in side effects, as well as the extreme fragility of the patient, should be considered. Anticoagulant therapy is also a complex challenge to address, as bleeding and stroke risk scores have not been fully assessed in this subpopulation. Furthermore, in large studies establishing the efficacy of direct oral anticoagulants (DOACs), cancer patients have been underrepresented. In this review, we elaborate on the mechanisms linking AF to cancer patients with a particular focus on the therapeutic challenges in this population.

Management of Patients Treated with Direct Oral Anticoagulants in Clinical Practice and Challenging Scenarios

It is well established that direct oral anticoagulants (DOACs) are the cornerstone of anticoagulant strategy in atrial fibrillation (AF) and venous thromboembolism (VTE) and should be preferred over vitamin K antagonists (VKAs) since they are superior or non-inferior to VKAs in reducing thromboembolic risk and are associated with a lower risk of intracranial hemorrhage (IH). In addition, many factors, such as fewer pharmacokinetic interactions and less need for monitoring, contribute to the favor of this therapeutic strategy. Although DOACs represent a more suitable option, several issues should be considered in clinical practice, including drug-drug interactions (DDIs), switching to other antithrombotic therapies, preprocedural and postprocedural periods, and the use in patients with chronic renal and liver failure and in those with cancer. Furthermore, adherence to DOACs appears to remain suboptimal. This narrative review aims to provide a practical guide for DOAC prescription and address challenging scenarios.

Prognostic implications of adherence to oral anticoagulants among patients with atrial fibrillation: Insights from MISOAC-AF trial

OBJECTIVES

To explore the implications of adherence to oral anticoagulants (OACs) on all-cause mortality and cardiovascular outcomes in patients with atrial fibrillation (AF).

METHODS

This post-hoc analysis of the MISOAC-AF trial included recently hospitalized patients with AF. Adherence to OACs was assessed by the proportion of days covered (PDC). Good adherence was defined as PDC >80 %. Cox regression models were used to associate PDC with clinical outcomes of all-cause death, cardiovascular death (CVD), stroke, and bleeding. A sub-analysis was performed among adherent patients to compare outcomes between vitamin K antagonists (VKAs) and direct oral anticoagulants (DOACs).

RESULTS

During a median 31-month follow-up, 778 cardiac patients with comorbid AF who had been prescribed OACs upon hospital discharge were studied. The mean PDC was 0.78; 66 % of patients had good adherence (>80 %) which was associated with lower risk of all-cause death [adjusted hazard ratio (aHR): 0.64; 95 % confidence interval (CI): 0.46 to 0.84, p < 0.001] and CVD (aHR: 0.70; 95 % CI: 0.50 to 0.97, p = 0.03). The risk of stroke and major or non-major bleeding did not differ by adherence status. Among adherent patients to OACs, VKA use was associated with higher rates of all-cause death (p < 0.001), CVD (p < 0.001), and stroke (p = 0.01); no differences were found regarding major or non-major bleeding risk.

CONCLUSIONS

In recently hospitalized patients with AF, good adherence to OACs was associated with a reduced risk of all-cause death and CVD. The rates of stroke or bleeding events were not significantly different. VKAs were associated with more adverse events compared to DOACs.

Bleeding and thrombotic events in atrial fibrillation patients with cancer: a systematic review and meta-analysis

Atrial fibrillation (AF) and cancer are frequently coexisting in elderly patients. Pooled metanalytic data on the impact of cancer on clinical outcomes in AF patients are lacking. We performed a systematic review and meta-regression analysis of clinical studies retrieved from Medline (PubMed) and Cochrane (CENTRAL) databases according to PRISMA guidelines. Bleeding endpoints included any, major, gastrointestinal (GI) bleeding and intracranial haemorrhage (ICH). Cardiovascular (CV) endpoints included myocardial infarction (MI), ischemic stroke/systemic embolism (IS/SE), CV and all-cause death. PROSPERO registration number: CRD42022315678. We included 15 studies with 2,868,010 AF patients, of whom 479,571 (16.7%) had cancer. The pooled hazard ratio (HR) for cancer was 1.43 (95% confidence interval [95%CI] 1.42-1.44) for any bleeding, 1.27 (95% CI 1.26-1.29) for major bleeding, 1.17 (95% CI 1.14-1.19) for GI bleeding, and 1.07 (95% CI 1.04-1.11) for ICH. The risk of major bleeding increased with the proportion of breast cancer. Cancer increased the risk of all-cause death (HR 2.00, 95% CI 1.99-2.02) whereas no association with MI and CV death was found. Patients with AF and cancer were less likely to suffer from IS/SE (HR 0.91, 95% CI 0.89-0.94). Cancer complicates the clinical history of AF patients, mainly increasing the risk of bleeding. Further analyses according to the type and stage of cancer are necessary to better stratify bleeding risk in these patients.

Effect of direct oral anticoagulants in patients with atrial fibrillation with mitral or aortic stenosis: A review

Background

Several studies have summarized the clinical performance of direct oral anticoagulants (DOACs) in atrial fibrillation (AF) patients with mitral stenosis or aortic stenosis. The significance of this review was to provide clinicians the latest update of the clinical application of DOACs in managing this specific population.

Methods

Literatures from the PubMed database up to July 2022 were screened for inclusion. Studies on the effect of DOACs in patients suffering from AF with mitral or aortic stenosis were assessed for further selection.

Results

Results from four studies were gathered: the RISE MS trial, the DAVID-MS study, and two observational studies. In the Korean observational study with a 27-month follow-up duration and a sample population consisted of patients with mitral stenosis and AF, the thromboembolic events happened at a rate of 2.22%/ year in the DOAC group and 4.19%/year in the warfarin group (adjusted hazard ratio: 0.28; 95% CI: 0.18–0.45). Intracranial hemorrhage occurred at rates of 0.49% and 0.93% in the DOAC and the warfarin groups, respectively (adjusted hazard ratio: 0.53; 95% CI: 0.22–1.26). In the Danish observational study, which had a sample pool with AF patients with aortic stenosis, reported that the adjusted hazard ratios for thromboembolism and major bleeding were 1.62 (95% CI, 1.08–2.45) and 0.73 (95% CI, 0.59–0.91) for DOACs compared with warfarin during 3 years of follow-up. In the RISE-MS trial involving AF patients with mitral stenosis, there were no differences in ischemic stroke, systemic embolic events, or major bleeding between the rivaroxaban vs. warfarin groups during a 1-year follow-up as well as equal rate of increased thrombogenicity in the left atrial appendage at 6 months. The rate of silent cerebral ischemia at 12 months was higher in the warfarin group (17.6%) than that in the rivaroxaban group (13.3%).

Conclusions

Current published studies supported DOACs' effectiveness in preventing thromboembolism in patients of AF with mitral or aortic stenosis. Further clinical trials could confirm these findings.

Superiority of Direct Oral Anticoagulants over Vitamin K Antagonists in Oncological Patients with Atrial Fibrillation: Analysis of Efficacy and Safety Outcomes

Background and aim. Cancer and atrial fibrillation (AF) may be associated, and anticoagulation, either with vitamin K antagonists (VKAs) or direct oral anticoagulants (DOACs), is necessary to prevent thromboembolic events by reducing the risk of bleeding. The log incidence rate ratio (IRR) and 95% confidence interval were used as index statistics. Higgin’s I2 test was adopted to assess statistical inconsistencies by considering interstudy variations, defined by values ranging from 0 to 100%. I2 values of less than 40% are associated with very low heterogeneity among the studies; values between 40% and 75% indicate moderate heterogeneity, and those greater than 75% suggest severe heterogeneity. The aim of this meta-analysis was to compare the safety and efficacy of VKAs and DOACs in oncologic patients with AF. Methods. A meta-analysis was conducted comparing VKAs to DOACs in terms of thromboembolic events and bleeding. A meta-regression was conducted to investigate the differences in efficacy and safety between four different DOACs. Moreover, a sub-analysis on active-cancer-only patients was conducted. Results. A total of eight papers were included. The log incidence rate ratio (IRR) for thromboembolic events between the two groups was −0.69 (p < 0.005). The meta-regression did not reveal significant differences between the types of DOACs (p > 0.9). The Log IRR was −0.38 (p = 0.008) for ischemic stroke, −0.43 (p = 0.02) for myocardial infarction, −0.39 (p = 0.45) for arterial embolism, and −1.04 (p = 0.003) for venous thromboembolism. The log IRR for bleeding events was −0.43 (p < 0.005), and the meta-regression revealed no statistical difference (p = 0.7). The log IRR of hemorrhagic stroke, major bleeding, and clinically relevant non-major bleeding between the VKA and DOAC groups was −0.51 (p < 0.0001), −0.45 (p = 0.03), and 0.0045 (p = 0.97), respectively. Similar results were found in active-cancer patients for all the endpoints except for clinically-relevant non-major bleedings. Conclusions. DOACs showed better efficacy and safety outcomes than VKAs. No difference was found between types of DOACs.

Direct oral anticoagulants for the treatment of atrial fibrillation in patients with hematologic malignancies

Atrial fibrillation (AF) is common in patients with cancer due to both the proinflammatory effect of neoplastic cells and to cardiotoxicity of anti-tumor therapies. Anticoagulation is still challenging in cancer patients due to increased bleeding risk related to specific neoplasms such us hematologic malignancies. The aim of this retrospective study was to evaluate the safety and the efficacy of direct oral anticoagulants (DOACs) in AF patients affected by hematologic neoplasms. We included 97 patients on active anticancer treatment. The median follow-up was 25 months (range 10-108). No thromboembolic complications occurred, while 14 bleeding events were recorded: 1 major, 12 clinical relevant non major bleeding and 1 minor bleeding. Although retrospective and with a small number of enrolled patients, our data support the efficacy and safety of DOACs in patients affected by hematologic malignancies suggesting caution to particular situations, such as thrombocytopenia.

Is the Risk of Diabetes Lower in Patients With Atrial Fibrillation Treated With Direct Oral Anticoagulant Compared to Warfarin?

Background

The use of anticoagulants is an established strategy to prevent stroke, embolism, and cardiovascular mortality in patients with atrial fibrillation (AF), but its role in the prevention of incident diabetes is unclear. We aimed to investigate this question by using participant data from cohort studies.

Methods

We conducted a meta-analysis of participants to investigate the impact of direct oral anticoagulants (DOACs) on the risk of new-onset diabetes in AF patients. The collection of related data was performed in the PubMed and EMBASE databases until December 2021, including studies associated with evaluating the correlation between DOACs and incident diabetes. The hazard ratios (HRs) and 95% confidence intervals (CIs) were adjusted by the random-effects model with an inverse variance method.

Results

Two cohort studies with a total of 24,434 patients were included in this study (warfarin: n = 6,906; DOACs: n = 17,528). Compared with warfarin, the use of DOACs could reduce the incident diabetic risk in AF patients (HR = 0.75, 95%CI: 0.68–0.82). Investigations about the effects of three major classes of DOACs showed that the individual use of dabigatran (HR = 0.76, 95%CI: 0.64–0.90), rivaroxaban (HR = 0.74, 95%CI: 0.64–0.87), apixaban (HR = 0.74, 95%CI: 0.60–0.92) and the combined use of rivaroxaban and apixaban (HR = 0.74, 95%CI: 0.66–0.84) could reduce the risk of new-onset diabetes compared with warfarin. This risk reduction effect could be observed in both male and female groups (HR = 0.73, 95%CI: 0.64–0.84, P &lt; 0.00001; HR = 0.82, 95%CI: 0.82–0.99, P = 0.04).

Conclusions

Treatment with DOACs compared with warfarin reduced the risk of new-onset diabetes in both male and female patients with AF.

Higher Mortality Associated With New-Onset Atrial Fibrillation in Cancer Patients: A Systematic Review and Meta-Analysis

Aim

This research was conducted to evaluate the mortality outcome of cancer patients with new-onset atrial fibrillation. We also aimed to assess if there was any confounding relation between the mortality of these patients and surgical intervention.

Materials and Methods

A systemic search was conducted from electronic databases (PubMed/Medline, Cochrane Library, and Google Scholar) from inception to 7 February 2022. All statistical analyses were conducted in Review Manager 5.4.1. Studies meeting inclusion criteria were selected. Only those studies that involved cancer patients without pre-existing atrial fibrillation were selected, and mortality rate was compared between the patients who developed atrial fibrillation and those who did not. A random-effect model was used when heterogeneity was seen to pool the studies, and the result was reported in the odds ratio (OR) and the corresponding 95% confidence interval (CI).

Results

Eighteen studies were selected for meta-analysis. Statistical analysis showed that the cancer patients who subsequently developed atrial fibrillation had a significantly higher mortality rate as compared to those who did not (OR = 1.90 [1.65, 2.19]; p &lt; 0.00001; I2 = 100%). We also separately analyzed the mortality risk in the surgery group and the non-surgery group. Statistical analysis showed that there was significantly higher mortality rate associated with new-onset atrial fibrillation in cancer patients in the surgery group (OR= 3.68 [2.29, 5.94]; p &lt; 0.00001; I2 = 61%) as well as in the non-surgery group (OR = 1.64 [1.39, 1.93]; p &lt; 0.00001; I2 = 100%).

Conclusion

Cancer patients, who subsequently developed atrial fibrillation, had a higher mortality rate as compared to those cancer patients who did not develop atrial fibrillation. A higher mortality rate was seen in both surgical and non-surgical subgroups. This implies that extra care and specific measures must be taken in the management of cancer patients with new-onset atrial fibrillation.