Lindsey R. Sangaralingham

Effect of Adherence to Oral Anticoagulants on Risk of Stroke and Major Bleeding Among Patients With Atrial Fibrillation

Background In comparison to warfarin, non–vitamin K antagonist oral anticoagulants (NOACs) have the advantages of ease of dosing, fewer drug interactions, and lack of need for ongoing monitoring. We sought to evaluate whether these advantages translate to improved adherence and whether adherence is associated with improved outcomes in patients with atrial fibrillation. Methods and Results We performed a retrospective cohort analysis by using a large US commercial insurance database to identify 64 661 patients with atrial fibrillation who initiated warfarin, dabigatran, rivaroxaban, or apixaban treatment between November 1, 2010, and December 31, 2014. During a median of 1.1 y of follow‐up, 47.5% of NOAC patients had a proportion of days covered of ≥80%, compared with 40.2% in warfarin patients (P<0.001). Patients with CHA 2 DS 2‐VASc (risk based on the presence of congestive heart failure, hypertension age 65–74 y, age ≥75 y, diabetes mellitus, prior stroke or transient ischemic attack, vascular disease, sex category) score ≥4 were at increased risk of stroke when they were not taking anticoagulation ≥1 month versus <1 week (1–3 months: hazard ratio [HR] 1.96, 3–6 months: HR 2.64, ≥6 months: HR 3.66; all P<0.001). Patients with CHA 2 DS 2‐VASc score 2 or 3 were at increased risk of stroke when they were not taking anticoagulation ≥6 months (HR 2.73, P<0.001). In these patients with CHA 2 DS 2‐VASc score ≥2, nonadherence was not associated with intracranial hemorrhage. Among patients with CHA 2 DS 2‐VASc score 0 or 1, time not taking anticoagulation was not associated with stroke, but not taking anticoagulation ≥3 months was associated with a significant reduction of bleeding. Conclusions Adherence to anticoagulation is poor in practice and may be modestly improved with NOACs. Adherence to therapy appears to be most important in patients with CHA 2 DS 2‐VASc score ≥2, whereas the benefits of anticoagulation may not outweigh the harms in patients with CHA 2 DS 2‐VASc score 0 or 1.

Effectiveness and Safety of Dabigatran, Rivaroxaban, and Apixaban Versus Warfarin in Nonvalvular Atrial Fibrillation

Background The introduction of non–vitamin K antagonist oral anticoagulants has been a major advance for stroke prevention in atrial fibrillation; however, outcomes achieved in clinical trials may not translate to routine practice. We aimed to evaluate the effectiveness and safety of dabigatran, rivaroxaban, and apixaban by comparing each agent with warfarin. Methods and Results Using a large US insurance database, we identified privately insured and Medicare Advantage patients with nonvalvular atrial fibrillation who were users of apixaban, dabigatran, rivaroxaban, or warfarin between October 1, 2010, and June 30, 2015. We created 3 matched cohorts using 1:1 propensity score matching: apixaban versus warfarin (n=15 390), dabigatran versus warfarin (n=28 614), and rivaroxaban versus warfarin (n=32 350). Using Cox proportional hazards regression, we found that for stroke or systemic embolism, apixaban was associated with lower risk (hazard ratio [HR] 0.67, 95% CI 0.46–0.98, P=0.04), but dabigatran and rivaroxaban were associated with a similar risk (dabigatran: HR 0.98, 95% CI 0.76–1.26, P=0.98; rivaroxaban: HR 0.93, 95% CI 0.72–1.19, P=0.56). For major bleeding, apixaban and dabigatran were associated with lower risk (apixaban: HR 0.45, 95% CI 0.34–0.59, P<0.001; dabigatran: HR 0.79, 95% CI 0.67–0.94, P<0.01), and rivaroxaban was associated with a similar risk (HR 1.04, 95% CI 0.90–1.20], P=0.60). All non–vitamin K antagonist oral anticoagulants were associated with a lower risk of intracranial bleeding. Conclusions In patients with nonvalvular atrial fibrillation, apixaban was associated with lower risks of both stroke and major bleeding, dabigatran was associated with similar risk of stroke but lower risk of major bleeding, and rivaroxaban was associated with similar risks of both stroke and major bleeding in comparison to warfarin.

Non–Vitamin K Antagonist Oral Anticoagulant Dosing in Patients With Atrial Fibrillation and Renal Dysfunction

BACKGROUND Dose reduction of non-vitamin K antagonist oral anticoagulants (NOACs) is indicated in patients with atrial fibrillation (AF) with renal impairment. Failure to reduce the dose in patients with severe kidney disease may increase bleeding risk, whereas dose reductions without a firm indication may decrease the effectiveness of stroke prevention. OBJECTIVES The goal of this study was to investigate NOAC dosing patterns and associated outcomes, i.e., stroke (ischemic stroke and systemic embolism) and major bleeding in patients treated in routine clinical practice. METHODS Using a large U.S. administrative database, 14,865 patients with AF were identified who initiated apixaban, dabigatran, or rivaroxaban between October 1, 2010, and September 30, 2015. We examined use of a standard dose in patients with a renal indication for dose reduction (potential overdosing) and use of a reduced dose when the renal indication is not present (potential underdosing). Cox proportional hazards regression was performed in propensity score-matched cohorts to investigate the outcomes. RESULTS Among the 1,473 patients with a renal indication for dose reduction, 43.0% were potentially overdosed, which was associated with a higher risk of major bleeding (hazard ratio: 2.19; 95% confidence interval: 1.07 to 4.46) but no statistically significant difference in stroke (3 NOACs pooled). Among the 13,392 patients with no renal indication for dose reduction, 13.3% were potentially underdosed. This underdosing was associated with a higher risk of stroke (hazard ratio: 4.87; 95% confidence interval: 1.30 to 18.26) but no statistically significant difference in major bleeding in apixaban-treated patients. There were no statistically significant relationships in dabigatran- or rivaroxaban-treated patients without a renal indication. CONCLUSIONS In routine clinical practice, prescribed NOAC doses are often inconsistent with drug labeling. These prescribing patterns may be associated with worse safety with no benefit in effectiveness in patients with severe kidney disease and worse effectiveness with no benefit in safety in apixaban-treated patients with normal or mildly impaired renal function.

Thyroid hormone treatment among pregnant women with subclinical hypothyroidism: US national assessment

Objective To estimate the effectiveness and safety of thyroid hormone treatment among pregnant women with subclinical hypothyroidism. Design Retrospective cohort study. Setting Large US administrative database between 1 January 2010 and 31 December 2014. Participants 5405 pregnant women with subclinical hypothyroidism, defined as untreated thyroid stimulating hormone (TSH) concentration 2.5-10 mIU/L. Exposure Thyroid hormone therapy. Main outcome measure Pregnancy loss and other pre-specified maternal and fetal pregnancy related adverse outcomes. Results Among 5405 pregnant women with subclinical hypothyroidism, 843 with a mean pre-treatment TSH concentration of 4.8 (SD 1.7) mIU/L were treated with thyroid hormone and 4562 with a mean baseline TSH concentration of 3.3 (SD 0.9) mIU/L were not treated (P<0.01). Pregnancy loss was significantly less common among treated women (n=89; 10.6%) than among untreated women (n=614; 13.5%) (P<0.01). Compared with the untreated group, treated women had lower adjusted odds of pregnancy loss (odds ratio 0.62, 95% confidence interval 0.48 to 0.82) but higher odds of preterm delivery (1.60, 1.14 to 2.24), gestational diabetes (1.37, 1.05 to 1.79), and pre-eclampsia (1.61, 1.10 to 2.37); other pregnancy related adverse outcomes were similar between the two groups. The adjusted odds of pregnancy loss were lower in treated women than in untreated women if their pre-treatment TSH concentration was 4.1-10 mIU/L (odds ratio 0.45, 0.30 to 0.65) but not if it was 2.5-4.0 mIU/L (0.91, 0.65 to 1.23) (P<0.01). Conclusion Thyroid hormone treatment was associated with decreased risk of pregnancy loss among women with subclinical hypothyroidism, especially those with pre-treatment TSH concentrations of 4.1-10 mIU/L. However, the increased risk of other pregnancy related adverse outcomes calls for additional studies evaluating the safety of thyroid hormone treatment in this patient population.

Patterns of Anticoagulation Use and Cardioembolic Risk After Catheter Ablation for Atrial Fibrillation

Background There is significant practice variation in oral anticoagulation (OAC) use following catheter ablation for atrial fibrillation. It is not clear whether the risk of cardioembolism increases after discontinuation of OAC following catheter ablation. Methods and Results We identified 6886 patients within a large national administrative claims database who underwent catheter ablation for atrial fibrillation between January 1, 2005, and September 30, 2014. We assessed the effect of time off of OAC by CHA 2 DS 2‐VASc score (after adjusting for other comorbidities) on risk of cardioembolism, using Cox proportional hazards models. There was an increase in the use of non–vitamin K OAC after ablation from 0% in 2005 to 69.8% in 2014. OAC discontinuation was high, with only 60.5% and 31.3% of patients remaining on OAC at 3 and 12 months, respectively. The rate of discontinuation was higher in low‐risk patients (82% versus 62.5% at 12 months for CHA 2 DS 2‐VASc 0–1 versus ≥2, respectively; P<0.001). Stroke occurred in 1.4% of patients with CHA 2 DS 2‐VASc ≥2 and 0.3% of those with CHA 2 DS 2‐VASc 0 or 1 over the study follow‐up. The risk of cardioembolism in the first 3 months after ablation was increased among those with any time off OAC (hazard ratio 8.06 [95% CI 1.53–42.3], P<0.05). The risk of cardioembolism beyond 3 months was increased with OAC discontinuation among high‐risk patients (hazard ratio 2.48 [95% CI 1.11–5.52], P<0.05) but not low‐risk patients. Conclusion The overall risk of stroke in postablation patients is low; however, OAC discontinuation after ablation is common and is associated with increased risk of cardioembolism for all patients within the first 3 months and for high‐risk patients in the long term. Continuing OAC for at least 3 months in all patients and indefinitely in high‐risk patients appears to be the safest strategy.

Comparative Effectiveness and Safety of Anti–Tumor Necrosis Factor Agents in Biologic-Naive Patients With Crohn’s Disease

BACKGROUND & AIMS Inhibitors of tumor necrosis factor (anti-TNF agents) are the most effective therapy for Crohns disease (CD). We evaluated the real-world comparative effectiveness and safety of different anti-TNF agents (infliximab, adalimumab, and certolizumab pegol) in biologic-naive patients with CD in a retrospective, propensity-matched cohort study using a national administrative claims database (Optum Labs Data Warehouse). METHODS We identified 3205 biologic-naive patients with CD (mean age, 41 ± 15 years; 45% male; median follow-up period after anti-TNF therapy, 19 months; 44.5% on infliximab and 38.9% on adalimumab) who received their first prescription for an anti-TNF agent (infliximab, adalimumab, or certolizumab pegol) after a 12-month period without any anti-TNF treatment (baseline), and with a minimum follow-up period of 6 months after their initial anti-TNF prescription, between 2006 and 2014. The primary outcomes were all-cause and CD-related hospitalization, abdominal surgery, corticosteroid use, and serious infections. We performed a propensity-matched, Cox proportional hazards analysis, accounting for baseline demographics, health care use, comorbidities, and use of CD-related medication. RESULTS Compared with adalimumab-treated patients, infliximab-treated patients had a lower risk of CD-related hospitalization (adjusted hazard ratio [aHR], 0.80; 95% confidence interval [CI], 0.66-0.98), abdominal surgery (aHR, 0.76; 95% CI, 0.58-0.99), and corticosteroid use (aHR, 0.85; 95% CI, 0.75-0.96). Compared with certolizumab pegol-treated patients, infliximab-treated patients had a lower risk of all-cause hospitalization (aHR, 0.70; 95% CI, 0.52-0.95) and CD-related hospitalization (aHR, 0.59; 95% CI, 0.39-0.90). Adalimumab-treated patients had outcomes comparable with those of certolizumab pegol-treated patients. All agents had comparable risk of serious infections. CONCLUSIONS In a retrospective analysis of a large cohort of biologic-naive patients with CD, we found infliximab to be superior to adalimumab and certolizumab pegol for patient-relevant outcomes, without increased risk of serious infections.

Trends and predictors of repeat catheter ablation for atrial fibrillation.

BACKGROUND Atrial fibrillation (AF) ablation is superior to pharmacologic therapy in achieving maintenance of normal sinus rhythm in selected patient populations. However, the procedure is resource intensive, and repeat ablations are sometimes required. We examined the predictors and trends of repeat ablation using a large national administrative claims database. METHODS Privately insured and Medicare Advantage patients who underwent catheter ablation for AF between January 1, 2004, and September 30, 2014, were included in the study. The primary outcome was repeat AF ablation during enrollment. We examined the associations between repeat ablation and patient demographics (age, gender, socioeconomic demographics), comorbid conditions (CHA2DS2-Vasc score and Charlson index), and year of the index ablation. Cox proportional hazard models were used to identify predictors of repeat ablation. RESULTS We included 8,648 adult patients in the analysis. Median age was 61.0 (interquartile range [IQR] 54-68) years, and 70.9% were men. Median follow-up was 1.1 (IQR 0.5-2.3) years. A total of 1,263 patients underwent repeat ablation (14.6%) over a total of 14,280 person-years (12.1% at 1 year). The hazard ratio (HR) for repeat ablation was higher in younger patients (HR 0.75 [0.61-0.91; P < .01] for age 65-75 and 0.55 [0.4-0.75; P < .001] for age ≥ 75 compared with age 18-54), those with higher household income (HR 1.24 [1-1.54; P < .05] for household income ≥

Comparative effectiveness and safety of infliximab and adalimumab in patients with ulcerative colitis

100,000 compared with household income <

Incidence and Early Outcomes of Heart Failure in Commercially Insured and Medicare Advantage Patients, 2006 to 2014

40,000), patients treated in the south (HR 1.15 [1-1.31]; P < .05), and those on antiarrhythmic medications (HR 1.15 [1.01-1.31]; P < .05). In particular, younger patients (ages 18-54 years) continued to undergo repeat ablations over the entire follow-up period, and the cumulative rate was approximately 40% among those followed for 5 years. Clinical characteristics including those included in the CHA2DS2-Vasc score and Charlson index did not predict likelihood of repeat ablation. The rate of repeat ablation remained constant over the available follow-up. CONCLUSION Approximately 1 in 8 patients treated with catheter ablation for AF will undergo a second procedure within 1 year, although the rate is as high as 40% in young patients at 5 years. The rate of repeat ablation appears to be associated with demographic characteristics (younger age and higher household income) rather than medical comorbidities.

Comparison of the CHA2DS2-VASc, CHADS2, HAS-BLED, ORBIT, and ATRIA Risk Scores in Predicting Non–Vitamin K Antagonist Oral Anticoagulants-Associated Bleeding in Patients With Atrial Fibrillation

Real‐world comparative benefits and risks of infliximab (IFX) and adalimumab (ADA) in patients with ulcerative colitis (UC) are unclear.