ObjectiveTo find out the effect of different oral anticoagulation therapies (OAC) on mortality rate in patients with acute kidney injury (AKI) and atrial fibrillation (AF).DesignA retrospective study.SettingThis study was conducted in the Medical Information Mart for Intensive Care IV database.ParticipantsA total of 19 672 patients diagnosed with AKI.Main outcome measuresPatients were categorised into three groups: (1) AF; (2) AKI and AF, OAC−; (3) AKI and AF, OAC+. The primary endpoint was 30-day mortality. Secondary endpoints were the length of stay (LOS) in the intensive care unit (ICU) and hospital. Propensity score matching (PSM) and Cox proportional hazards model adjusted confounding factors. Linear regression was applied to assess the associations between OAC treatment and LOS.ResultsAfter PSM, 2042 pairs of AKI and AF patients were matched between the patients who received OAC and those without anticoagulant treatment. Cox regression analysis showed that, OAC significantly reduce 30-day mortality compared with non-OAC (HR 0.30; 95% CI 0.25 to 0.35; p<0.001). Linear regression analysis revealed that OAC prolong LOS in hospital (11.3 days vs 10.0 days; p=0.013) and ICU (4.9 days vs 4.4 days; p<0.001). OAC did not improve survival in patients with haemorrhage (HR 0.67; 95% CI 0.34 to 1.29; p=0.23). Novel OAC did not reduce mortality in acute-on-chronic renal injury (HR 2.03; 95% CI 1.09 to 3.78; p=0.025) patients compared with warfarin.ConclusionOAC administration was associated with improved short-term survival in AKI patients concomitant with AF.