Acute Kidney Injury in Patients with Non-Valvular Atrial Fibrillation Treated with Rivaroxaban or Warfarin: A Population-Based Study from the United Kingdom

Antonio González-Pérez; Yanina Balabanova; María E Sáez; Gunnar Brobert; Luis A García Rodríguez

doi:10.2147/CLEP.S383996

Acute Kidney Injury in Patients with Non-Valvular Atrial Fibrillation Treated with Rivaroxaban or Warfarin: A Population-Based Study from the United Kingdom

Clin Epidemiol. 2022 Nov 2:14:1281-1291. doi: 10.2147/CLEP.S383996. eCollection 2022.

Authors

Antonio González-Pérez¹, Yanina Balabanova², María E Sáez¹, Gunnar Brobert³, Luis A García Rodríguez¹

Affiliations

¹ Pharmacoepidemiology, Spanish Centre for Pharmacoepidemiologic Research (CEIFE), Madrid, Spain.
² Integrated Evidence Generation, Bayer AG, Berlin, Germany.
³ Integrated Evidence Generation, Bayer AB, Stockholm, Sweden.

Abstract

Purpose: To compare the risk of acute kidney injury (AKI) among users of rivaroxaban vs warfarin.

Patients and methods: We identified two cohorts of patients with non-valvular atrial fibrillation (NVAF) who initiated rivaroxaban (15/20 mg/day, N = 6436) or warfarin (N = 7129) excluding those without estimated glomerular filtration rate values recorded in the year before oral anticoagulant (OAC) initiation and those with a history of end-stage renal disease or AKI. We used two methods to define AKI during follow-up (mean 2.5 years): coded entries (method A) and the Aberdeen AKI phenotyping algorithm (method B) using recorded renal function laboratory values during the study period to identify a sudden renal deterioration event. Cox regression was used to calculate hazard ratios (HRs) for AKI with rivaroxaban vs warfarin use, adjusted for confounders.

Results: The number of identified incident AKI cases was 249 (method A) and 723 (method B). Of the latter, 104 (14.4%) were also identified by method A. After adjusting for age, sex, baseline renal function and comorbidity, HRs (95% CIs) for AKI were 1.19 (0.92-1.54; p=0.18) using method A and 0.80 (0.68-0.93; p<0.01) using method B. Estimates stratified by baseline level of chronic kidney disease were largely consistent with the main estimates.

Conclusion: Our results support a beneficial effect of rivaroxaban over warfarin in terms of AKI occurrence in patients with NVAF. More research into how best to define AKI using primary care records would be valuable for future studies.

Keywords: cohort study; database; oral anticoagulation; renal injury.

Grants and funding

This study was funded by Bayer AG (grant number not applicable). Bayer AG had no role in the design or conduct of the study aside from the roles carried out by YB (current employee of Bayer) and GB (former employee of Bayer) as described below.