Positive Predictive Value of Non-Traumatic Bleeding Diagnoses in the Danish National Patient Register

External Validation of the OAC3-PAD Bleeding Score in a Nationwide Population of Patients Undergoing Invasive Treatment for Peripheral Arterial Disease

OBJECTIVE

The OAC3-PAD score was developed to predict bleeding risk in patients with lower extremity peripheral arterial disease (PAD), but its performance in concomitant international cohorts is largely unknown. This study aimed to validate the OAC3-PAD score in an unselected nationwide population of patients undergoing invasive treatment for symptomatic PAD.

METHODS

This was a nationwide cohort study including all patients who underwent a first revascularisation procedure or major amputation for symptomatic PAD in Denmark from 2000 - 2021. The study population was stratified based on OAC3-PAD score, and the one year risk of major bleeding was assessed, accounting for the competing risk of death. The score performance was evaluated using calibration plots, C statistic, Brier score, and the index of prediction accuracy (IPA).

RESULTS

A total of 52 016 patients were included (mean age 71 years, 43.8% female). The one year risk of major bleeding increased with higher OAC3-PAD score, ranging from 1.6% (95% confidence interval [CI] 1.4 - 1.8%) to 2.3% (95% CI 2.0 - 2.5%), 3.5% (95% CI 3.2 - 3.8%), and 5.2% (95% CI 4.8 - 5.6%) for patients with low, low moderate, moderate high, and high score, respectively. Using patients with low risk as reference, the OAC3-PAD score effectively categorised patients, demonstrating statistically significant differences in bleeding risk across strata. However, the score showed modest discriminative performance, with a C statistic of 65% (95% CI 63 - 66%) and a Brier score of 2.6% (95% CI 2.5 - 2.7%). Nevertheless, it performed significantly better than the null model, as indicated by an IPA of 3.1%.

CONCLUSION

Among patients who underwent invasive treatment for symptomatic PAD in routine care, the OAC3-PAD score was associated with greater risk of major bleeding with increasing score level. However, its discriminatory ability was modest, and the clinical utility remains to be determined.

Gastrointestinal bleeding with direct oral anticoagulants in patients with atrial fibrillation and anaemia

INTRODUCTION

A high risk of gastrointestinal bleeding has been reported with the use of some direct oral anticoagulants (DOACs). This risk may be of particular concern in individuals with associated anaemia. The aim of this study is to investigate potential differences in the risks of gastrointestinal bleeding and stroke among the four available DOACs in patients with atrial fibrillation (AF) and moderate or severe anaemia.

MATERIALS AND METHODS

All Danish patients diagnosed with incident AF who had a baseline haemoglobin measurement and subsequently initiated DOAC therapy between 2012 and 2021 were identified through administrative registries. Only patients with moderate or severe anaemia (N = 7269) were included and evaluated regarding the risk of hospitalization for gastrointestinal bleeding and stroke. Standardized absolute 1-year risks of stroke and gastrointestinal bleeding were calculated from multivariable Cox regression analyses. DOACs were compared pairwise RESULTS: Compared with apixaban, both dabigatran and rivaroxaban were associated with a significantly increased risk of gastrointestinal bleeding with standardized 1-year risk ratios of 1.73 (95 % confidence interval [CI], 1.10-2.35) and 1.56 (95 % CI, 1.18-1.93), respectively, while no significant difference was seen in the comparison of apixaban with edoxaban 1.32 (95 % CI, 0.41-2.32). No significant differences in gastrointestinal bleeding were observed with pairwise comparisons of dabigatran, rivaroxaban and edoxaban. Finally, no significant difference in stroke risk among the four DOACs was observed.

CONCLUSION

In AF patients with moderate or severe anaemia, apixaban was associated with a significantly lower risk of gastrointestinal bleeding than dabigatran and rivaroxaban. No significant difference in stroke risk was observed across all four available DOACs.

Antiplatelet Therapy in Patients With Abdominal Aortic Aneurysm Without Symptomatic Atherosclerotic Disease

Importance

Patients with abdominal aortic aneurysm have a high risk of ischemic events associated with concomitant atherosclerotic cardiovascular disease, and current clinical practice guidelines recommend antiplatelet therapy to mitigate this risk. However, in patients with aneurysms without symptomatic atherosclerosis, the benefit of antiplatelet therapy has been sparsely investigated.

Objective

To estimate the effect of antiplatelets on the risk of ischemic events and bleeding in individuals with abdominal aneurysms with no symptomatic atherosclerotic vascular disease.

Design, Setting, and Participants

A comparative effectiveness research study using a target trial emulation framework was performed. Population-based, cross-linked observational data from Danish national health registries containing comprehensive, individual-level information on all Danish citizens were used to evaluate patients who were antiplatelet-naive and diagnosed with abdominal aortic aneurysms, with no record of symptomatic atherosclerotic vascular disease, from January 1, 2010, through August 21, 2021.

Exposure

Prescription filled for aspirin or clopidogrel.

Main Outcomes and Measures

Risk of ischemic events (myocardial infarction and/or ischemic stroke) and risk of major bleeding. For target trial emulation, trials were emulated as sequential, contingent on patient eligibility at the time of inclusion, and were evaluated by means of pooled logistic regression models to estimate the intention-to-treat and as-treated effects, expressed as hazard ratio (HR) and event-free survival.

Results

A total of 6344 patients (65.2% men; age, 72 [IQR, 64-78] years) provided 131 047 trial cases; 3363 of these cases involved initiation of antiplatelet therapy and 127 684 did not. A total of 182 ischemic events occurred among initiators and 5602 ischemic events occurred among noninitiators, corresponding to an intention-to-treat HR of 0.91 (95% CI, 0.73-1.17) and an estimated absolute event-free survival difference of -0.6% (95% CI, -1.7% to 0.5%). After censoring nonadherent person-time, the treatment HR was 0.90 (95% CI, 0.68-1.20), with similar risk difference. For bleeding, the intention-to-treat HR was 1.26 (95% CI, 0.97-1.58) and the event-free survival difference was 1.0%. The treatment HR was 1.21 (95% CI, 0.82-1.72); the risk difference was similar.

Conclusions and Relevance

In this study, no evidence of effectiveness of antiplatelet therapy to lower the risk of ischemic events and a trend toward higher bleeding risk was noted. The observed differences between the treatment groups were minimal, suggesting limited clinical relevance of antiplatelet treatment.