Moderated Poster Australian and New Zealand Stroke Organisation Conference 2025

Association of anticoagulant and proton pump inhibitor use with vascular outcomes in patients with atrial fibrillation in New Zealand (121519)

Karim Mahawish 1 2 , Irene Zeng 3 , Harvey White 4 , Valery Feigin 1 , Rita Krishnamurthi 1
  1. The National Institute for Stroke and Applied Neurosciences, Auckland University of Technology, Auckland, Auckland Region, New Zealand
  2. Stroke Department, Health New Zealand Te Whatu Ora, Counties Manukau, Auckland, Auckland Region, New Zealand
  3. School of Clinical Science, Faculty of Health and Environmental Science, Auckland University of Technology, Auckland, Auckland Region, New Zealand
  4. Green Lane Cardiovascular Service, Health New Zealand Te Whatu Ora, Te Toka Tumai Auckland, Auckland City Hospital, New Zealand, Auckland, New Zealand

Background/Aims: Anticoagulants have reduced ischemic stroke (IS) risk in atrial fibrillation (AF), while the use of proton pump inhibitors (PPIs) has increased and been linked to complications, including vascular events. In this observational study, we examined anticoagulant and PPI prescribing practices in AF patients using cases from the fifth Auckland Regional Community Stroke Study (ARCOS 2020-21) and controls from the New Zealand National Minimum Dataset (NMD).

Methods: Data on CHA2DS2 VA comorbidities (heart failure, hypertension, diabetes, vascular disease, age, previous IS/TIA), and anticoagulant/PPI type and dose were recorded. Descriptive statistics and logistic regression were used to analyse associations between covariates and the composite vascular outcome of IS/TIA, and interaction tests were conducted. 

Results: We identified 1168 controls and 163 cases, (median age 71.4 years [IQR 61.7-80.3]); 44.6% female. Anticoagulants were prescribed to 69.5% of patients (warfarin 16%, dabigatran 63%, rivaroxaban 22%), and vascular outcomes were reduced by half (p<0.01). One-third of patients were prescribed PPIs. Multivariable analysis showed that age ≥75 years, previous IS/TIA, and PPI use were associated with an increased risk of vascular outcomes (all p<0.05). A dose-response association was found between PPI use and vascular outcomes (aOR 2.16 [95%CI 1.38-3.36],p=0.001) for high-dose PPI (e.g. omeprazole≥40mgOD). Propensity score analysis matched on CHA2DS2 VA factors confirmed increased risk with PPI use (aOR 2.02 [95%CI 1.24-3.29],p<0.01). No significant statistical interaction was observed between PPI and anticoagulant type. 

Conclusion: PPI use in AF patients may increase vascular risk, highlighting the need for further research into its potential harm in this population.