Influence of Polypharmacy on the Effectiveness and Safety of Rivaroxaban Versus Warfarin in Patients With Nonvalvular Atrial Fibrillation.

STUDY OBJECTIVE: Patients with nonvalvular atrial fibrillation (NVAF) often have multiple comorbidities requiring concomitant medications in addition to their oral anticoagulant (OAC). The objective of this study was to evaluate the impact of polypharmacy on the effectiveness and safety of rivaroxaban versus warfarin in patients with NVAF managed in routine clinical practice. DESIGN: Retrospective claims analysis. DATA SOURCE: United States Truven MarketScan database (November 2012-March 2017). PATIENTS: Adults who were OAC naïve during the 12 months before the day of the first qualifying rivaroxaban or warfarin dispensing (index date); had at least two International Classification of Diseases, Ninth or Tenth Revision diagnosis codes for atrial fibrillation without codes suggesting valvular heart disease; had at least 12 months of continuous insurance coverage prior to the qualifying OAC dispensing; and were experiencing polypharmacy (concomitant prescription claims for five or more unique chronic medication claims) were included. Patients who had concomitant prescription claims for ≥ 10 unique chronic medication claims constituted the substantial polypharmacy cohort used in the secondary analysis. Patients receiving rivaroxaban were propensity-score matched in a 1:1 ratio to patients receiving warfarin (13,981 patients in each polypharmacy OAC group, and 1765 patients in each substantial polypharmacy OAC group). MEASUREMENTS AND MAIN RESULTS: Patients were followed until occurrence of an event (stroke or systemic embolism [SSE] combined [primary effectiveness outcome] or major bleeding [primary safety outcome]), OAC discontinuation or switch (30-day permissible gap), insurance disenrollment, or end of follow-up period. Rates of SSE, ischemic stroke, and major bleeding were compared by using Cox regression, reported as hazard ratios (HRs) and 95% confidence intervals (CIs). In patients with NVAF taking five or more chronic medications, rivaroxaban was associated with a 34% (95% CI 12-50) and 40% (95% CI 16-57) hazard reduction of SSE and ischemic stroke, respectively. Occurrence of major bleeding was similar between OAC cohorts (HR 1.08, 95% CI 0.92-1.28). A secondary analysis in patients with NVAF with substantial polypharmacy (taking ≥ 10 chronic medications) was also performed. Similar trends in SSE (HR 0.44), ischemic stroke alone (HR 0.62), and major bleeding (HR 1.07) were observed in patients with NVAF who had substantial polypharmacy, although 95% CIs crossed 1.0 for each outcome in this smaller study cohort. CONCLUSION: This real-world study suggests that in the setting of polypharmacy and NVAF, rivaroxaban is an effective and safe alternative to warfarin.

Effectiveness and safety of rivaroxaban vs. warfarin in patients with non-valvular atrial fibrillation and heart failure.

AIMS: Heart failure (HF) is a common co-morbidity in non-valvular atrial fibrillation (NVAF) patients and a potent risk factor for stroke, bleeding, and a decreased time-in-therapeutic range with warfarin. We assessed the real-world effectiveness and safety of rivaroxaban and warfarin in NVAF patients with co-morbid HF. METHODS AND RESULTS: Using US Truven MarketScan Commercial and Medicare supplemental database claims data from 11/2011 to 12/2016, we identified oral anticoagulant (OAC)-naïve NVAF patients with HF (International Classification of Diseases, 10th Revision codes of I50 or I09.81) and ≥12 months of insurance coverage prior to the qualifying OAC dispensing. Rivaroxaban users (20 or 15 mg once daily) were 1:1 propensity score matched to warfarin users, with residual absolute standardized differences <0.1 being achieved for all covariates after matching. Patients were followed up until an event, OAC discontinuation/switch, insurance disenrolment, or end of follow-up. Rates [events per 100 person-years (PYs) of follow-up] for stroke or systemic embolism and major bleeding (using the Cunningham algorithm) were compared between the matched cohorts using Cox proportion hazard regression and reported as hazard ratios (HRs) with 95% confidence intervals (CIs). We matched 3418 rivaroxaban (32% receiving the reduced dose) and 3418 warfarin users with NVAF and HF with a median (interquartile range) available follow-up of 1.4 (0.6, 2.5) years. Median age was 74 (63, 82) years, and median CHA2 DS2 -VASc and HASBLED scores were 4 (3, 5) and 2 (2, 3). Common HF medications included beta-blockers (64%), angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (62%), loop diuretics (46%), digoxin (11%), and aldosterone receptor antagonists (10%). The hazard of developing stroke or systemic embolism (0.98 events/100PY vs. 1.28 events/100PY; HR = 0.82, 95% CI = 0.47-1.44), ischaemic stroke (0.70 events/100PY vs. 1.02 events/100PY; HR = 0.77, 95% CI = 0.41-1.46), or major bleeding (3.86 events/100PY vs. 4.23 events/100PY; HR = 0.98, 95% CI = 0.73-1.31) was not found to be different between rivaroxaban and warfarin users. Intracranial haemorrhage was infrequent in both cohorts and numerically less with rivaroxaban (0.27 events/100PY vs. 0.36 events/100PY; HR = 0.73, 95% CI = 0.25-2.08). CONCLUSIONS: Effectiveness and safety of rivaroxaban vs. warfarin are sustained in NVAF patients with co-morbid HF treated in routine practice. The general consistency between this real-world study and those from phase III randomized trial data of rivaroxaban should provide additional reassurance to clinicians regarding the use of rivaroxaban in NVAF patients with HF.

Agreement between coding schemas used to identify bleeding-related hospitalizations in claims analyses of nonvalvular atrial fibrillation patients.

BACKGROUND: Schemas to identify bleeding-related hospitalizations in claims data differ in billing codes used and coding positions allowed. We assessed agreement across bleeding-related hospitalization coding schemas for claims analyses of nonvalvular atrial fibrillation (NVAF) patients on oral anticoagulation (OAC). HYPOTHESIS: We hypothesized that prior coding schemas used to identify bleeding-related hospitalizations in claim database studies would provide varying levels of agreement in incidence rates. METHODS: Within MarketScan data, we identified adults, newly started on OAC for NVAF from January 2012 to June 2015. Billing code schemas developed by Cunningham et al., the US Food and Drug Administration (FDA) Mini-Sentinel program, and Yao et al. were used to identify bleeding-related hospitalizations as a surrogate for major bleeding. Bleeds were subcategorized as intracranial hemorrhage (ICH), gastrointestinal (GI), or other. Schema agreement was assessed by comparing incidence, rates of events/100 person-years (PYs), and Cohen's kappa statistic. RESULTS: We identified 151 738 new-users of OAC with NVAF (CHA2DS2-VASc score = 3, [interquartile range = 2-4] and median HAS-BLED score = 3 [interquartile range = 2-3]). The Cunningham, FDA Mini-Sentinel, and Yao schemas identified any bleeding-related hospitalizations in 1.87% (95% confidence interval [CI]: 1.81-1.94), 2.65% (95% CI: 2.57-2.74), and 4.66% (95% CI: 4.55-4.76) of patients (corresponding rates = 3.45, 4.90, and 8.65 events/100 PYs). Kappa agreement across schemas was weak-to-moderate (κ = 0.47-0.66) for any bleeding hospitalization. Near-perfect agreement (κ = 0.99) was observed with the FDA Mini-Sentinel and Yao schemas for ICH-related hospitalizations, but agreement was weak when comparing Cunningham to FDA Mini-Sentinel or Yao (κ = 0.52-0.53). FDA Mini-Sentinel and Yao agreement was moderate (κ = 0.62) for GI bleeding, but agreement was weak when comparing Cunningham to FDA Mini-Sentinel or Yao (κ = 0.44-0.56). For other bleeds, agreement across schemas was minimal (κ = 0.14-0.38). CONCLUSIONS: We observed varying levels of agreement among 3 bleeding-related hospitalizations schemas in NVAF patients.