Stephen Sander

Higher Persistence in Newly Diagnosed Nonvalvular Atrial Fibrillation Patients Treated With Dabigatran Versus Warfarin

Background—Oral anticoagulation therapy is the primary tool in reducing stroke risk in patients with nonvalvular atrial fibrillation but is underused. Patients nonpersistent with therapy contribute to this underuse. The objective of this study was to compare persistence rates in newly diagnosed nonvalvular atrial fibrillation patients treated with warfarin versus dabigatran as their oral anticoagulation. Methods and Results—US Department of Defense administrative claims were used to identify patients receiving warfarin or dabigatran between October 28, 2010, and June 30, 2012. Patient records were examined for a minimum of 12 months before index date to restrict the analyses to those newly diagnosed with nonvalvular atrial fibrillation and naive-to-treatment, identifying 1775 on warfarin and 3370 on dabigatran. Propensity score matching was used to identify 1745 matched pairs. Persistence was defined as time on therapy to discontinuation. Kaplan–Meier curves were used to depict persistence over time. Cox proportional hazards model was used to determine the factors significantly associated with persistence. Using a 60-day permissible medication gap, the persistence rates were higher for dabigatran than for warfarin at both 6 months (72% versus 53%) and 1 year (63% versus 39%). Patients on dabigatran with a low-to-moderate risk of stroke (CHADS2<2) or with a higher bleed risk (HEMORR2HAGES>3) had a higher likelihood of nonpersistence (hazard ratios, 1.37; 95% confidence interval, 1.17–1.60; P<0.001; and hazard ratios, 1.24; 95% confidence interval, 1.04–1.47; P=0.016). Conclusions—Patients who initiated dabigatran treatment were more persistent than patients who began warfarin treatment. Within each cohort, patients with lower stroke risk were more likely to discontinue therapy.

Evaluating the impact of study-level factors on warfarin control in U.S.-based primary studies: A meta-analysis

PURPOSE The effect of study-level factors on the proportion of time spent with International Normalized Ratio (INR) values inside the therapeutic range in patients treated with warfarin in the United States was evaluated. METHODS Studies evaluated in a previous meta-analysis were screened for potential inclusion, in addition to a systematic literature search of databases from January 2005 through February 2008. Studies were included if they (1) contained at least one warfarin dosing group that enrolled >25 patients for whom INR control was monitored for at least three weeks, (2) included only patients treated in the United States, (3) used a patient-time approach to report outcomes, and (4) reported proportion of time spent in the therapeutic INR range. Analyses included determining how study-level factors, such as study setting, year of study publication, INR interpolation method, study design, and presence of self-management, affected outcomes. RESULTS Twenty-four studies, including a total of 43 unique warfarin groups, were included in the analysis. Overall, patients spent 57% of their time in the therapeutic range (95% confidence interval [CI], 55-59%). Compared with anticoagulation clinics, community management resulted in less time (-13%; 95% CI, -18% to -7.9%) and prospective studies resulted in more time (7.3%; 95% CI, 1.5-13.1%) spent in the therapeutic range than retrospective studies. When studies from both the United States and Canada were included, similar results to those in the base-case analysis were seen; however, study year and interpolation method were also found to be significant modifiers of INR control. CONCLUSION Patients included in the meta-analysis maintained INR values within the therapeutic range 57% of the time, although the use of anticoagulation clinic services appeared to be superior to standard community care in this regard. However, patients treated in anticoagulation clinics had INR values within the therapeutic range less than two thirds of the time.

Long-Term Costs of Ischemic Stroke and Major Bleeding Events among Medicare Patients with Nonvalvular Atrial Fibrillation

Purpose. Acute healthcare utilization of stroke and bleeding has been previously examined among patients with nonvalvular atrial fibrillation (NVAF). The long-term cost of such outcomes over several years is not well understood. Methods. Using 1999–2009 Medicare medical and enrollment data, we identified incident NVAF patients without history of stroke or bleeding. Patients were followed from the first occurrence of ischemic stroke, major bleeding, or intracranial hemorrhage (ICH) resulting in hospitalization. Those with events were matched with 1–5 NVAF patients without events. Total incremental costs of events were calculated as the difference between costs for patients with events and matched controls for up to 3 years. Results. Among the 25,465 patients who experienced events, 94.5% were successfully matched. In the first year after event, average incremental costs were

Costs and outcomes of noncardioembolic ischemic stroke in a managed care population.

32,900 for ischemic stroke,

Patterns and Predictors of Use of Warfarin and Other Common Long-Term Medications in Patients with Atrial Fibrillation

23,414 for major bleeding, and

Impact of persistence with antiplatelet therapy on recurrent ischemic stroke and predictors of nonpersistence among ischemic stroke survivors

47,640 for ICH. At 3 years after these events, costs remained elevated by

Anticoagulant Use, the Prevalence of Bridging, and Relation to Length of Stay among Hospitalized Patients with Non-Valvular Atrial Fibrillation

3,156–

Health Care Resource Utilization, Costs, and Persistence in Patients Newly Diagnosed as Having Nonvalvular Atrial Fibrillation and Newly Treated With Dabigatran versus Warfarin in the United States

5,400 per annum. Conclusion. While the costs of stroke and bleeding among patients with NVAF are most dramatic in the first year, utilization remained elevated at 3 years. Cost consequences extend beyond the initial year after these events and should be accounted for when assessing the cost-effectiveness of treatment regimens for stroke prevention.

Impact of atrial fibrillation and oral anticoagulation on hospital costs and length of stay

Purpose To evaluate the clinical outcomes and incremental health care costs of ischemic stroke in a US managed care population. Patients and methods A retrospective cohort analysis was done on patients (aged 18+ years) hospitalized with noncardioembolic ischemic stroke from January 1, 2002, through December 31, 2003, identified from commercial health plan administrative claims. New or recurrent stroke was based on history in the previous 12 months, with index date defined as first date of indication of stroke. A control group without stroke or transient ischemic attack (TIA) was matched (1:3) on age, sex, and geographic region, with an index date defined as the first medical claim during the patient identification period. Patients with atrial fibrillation or mitral value abnormalities were excluded. Ischemic stroke and control cohorts were compared on 4-year clinical outcomes and 1-year costs. Results Of 2180 ischemic stroke patients, 1808 (82.9%) had new stroke and 372 (17.1%) had a recurrent stroke. Stroke patients had higher unadjusted rates of additional stroke, TIA, and fatal outcomes compared with the 6540 matched controls. Recurrent stroke patients had higher rates of adverse clinical outcomes compared with new stroke patients; costs attributed to recurrent stroke were also higher. Stroke patients were 2.4 times more likely to be hospitalized in follow-up compared with controls (hazard ratio [HR] 2.4, 95% confidence interval [CI]: 2.2, 2.6). Occurrence of stroke following discharge was 21 times more likely among patients with index stroke compared with controls (HR 21.0, 95% CI: 16.1, 27.3). Stroke was also predictive of death (HR 1.8, 95% CI: 1.3, 2.5). Controlling for covariates, stroke patients had significantly higher costs compared with control patients in the year following the index event. Conclusion Noncardioembolic ischemic stroke patients had significantly poorer outcomes and higher costs compared with controls. Recurrent stroke appears to contribute substantially to these higher rates of adverse outcomes and costs.

Readmission among hospitalized patients with nonvalvular atrial fibrillation

AbstractBackground and Objective No study has been published that compared persistence and discontinuation of warfarin with other long-term medications in patients with atrial fibrillation (AF). The objective of this study was to evaluate persistence and discontinuation patterns in AF patients taking warfarin and other common long-term medications and identify predictors of persistence and discontinuation in this population. Methods Patients with warfarin prescription within 3 months after AF hospitalization discharge and 12-month data before and after the first prescription were evaluated using administrative claims data (1 January 2005–31 December 2007). For comparison, persistence patterns for other long-term medications for treatment of hypertension, hyperglycemia, heart disease, and dyslipidemia, including once- (od) and twice- (bid) daily medications, were evaluated. Non-persistence was defined as the presence of a ≥60-day gap in medication use. Permanent discontinuation was defined as no use of the medication for ≥90 days until the end of the follow-up period. Multivariate analysis was conducted to identify predictors of warfarin non-persistence and discontinuation. Results 28 384 patients with AF were identified; 16036 (56.5%) had a warfarin prescription following AF hospitalization. 53.5% of warfarin users were persistent for at least 1 year, similar to other long-term medications commonly prescribed to the AF population (ranging between 45.2% and 61.3%). 42.6% of warfarin users permanently discontinued warfarin within 1 year, also consistent with the discontinuation rate of 32.9–52.0% of other long-term medications. Residence in the South and West regions of the US, history of cardiac dysrhythmias, and warfarin cost-sharing significantly decreased the likelihood of warfarin persistence and increased the likelihood of discontinuation, while older age, history of ischemic stroke, and warfarin use before hospitalization significantly increased warfarin persistence and decreased the likelihood of discontinuation. Adherence of od and bid medications was similar. Conclusion Persistence and discontinuation with warfarin in patients with AF is consistent with other long-term medications. Identifying factors associated with non-persistence and discontinuation with long-term medications can help in developing targeted adherence programs.