Oral anticoagulation therapy and subsequent risk of venous thromboembolism in atrial fibrillation patients

Abstract

Objective: Oral anticoagulation (OAC) prescribed to AF patients for the prevention of cardioembolic complications likely has the added benefit of preventing venous thromboembolism (VTE). We evaluated, among AF patients who are anticoagulated, whether type of OAC was associated with subsequent VTE risk. Methods: Non-valvular AF patients prescribed OACs between 2010 and September 2015 were identified via the MarketScan administrative claims databases. OACs included warfarin and direct OACs (DOACs: dabigatran, rivaroxaban and apixaban). Incident VTE was defined by ICD-9-CM codes. Patients were matched on age, sex, CHA 2 DS 2-VASc and high-dimensional propensity scores. The final analysis included 117,912 AF patients. Results: 1,357 VTE events accrued over a mean follow-up of 484 days. In multivariableadjusted, propensity score-matched Cox models, relative to new users of warfarin, risk of incident VTE was lower among new users of dabigatran [hazard ratio (95% confidence interval): 0.55

Risk of hospitalised bleeding in comparisons of oral anticoagulant options for the primary treatment of venous thromboembolism

“…In sensitivity analyses, we adjusted for empirically‐defined high‐dimensional propensity scores (HDPS) (Schneeweiss et al , ) instead of the propensity scores created using the pre‐specfied comorbidities and medications. We have detailed our MarketScan HDPS approach previously (Lutsey et al , ). Separate high‐dimensional propensity scores were calculated for each of the three comparisons, and for the periods before and after ICD‐10 adoption (1 October 2015).…”

Atrial Fibrillation in Patients with Acute Pulmonary Embolism: Clinical Significance and Impact on Prognosis

“…There was no difference in VTE risk when comparing rivaroxaban to warfarin (1.01. (0.87-1.19)) [33]. Also, in a large cohort study, the risk of AF after a PE episode was attenuated after adjustment for anticoagulant therapy [5].…”

Critical appraisal and issues regarding generalisability of comparative effectiveness studies of NOACs in atrial fibrillation and their relation to clinical trial data: a systematic review

“…Five studies concerned elderly patients specifically (ie, ≥65 years old), 19 21 23–25 two included adults ≥45 years old 33 40 and one study included patients between 30 and 100 years of age. 44 The other studies included all adults with atrial fibrillation (it was assumed that if no further age specification was provided, ‘adults’ meant that all >18 years old were included).…”

“…However, in one of the articles, an extensive rationale and selection procedure of covariates that were included in the analysis was provided. 33 In three other studies, the authors selected covariates based on medical knowledge on risk factors with reference to earlier published studies. 31 39 52 In one other study, it was reported that sociodemographic and clinical characteristics that were associated with treatment initiation and the risk of major bleeding were included in the model to adjust for differences across cohorts, without further explanation or reference.…”

“… 16 19 20 26 30 32 36 Five other studies also matched 1:1 without replacement but used another calliper: in three studies, a calliper of 0.2 was used, 39 40 47 while two others used a calliper of <0.25. 33 35 In three studies, three-way matching was used. 21 34 37 …”