Abstract 12029: Association of Out-of-Range International Normalized Ratio (INR) Values and Adverse Clinical Outcomes Among Newly Initiated Warfarin Patients With Non-Valvular Atrial Fibrillation and Comorbid Diabetes
Introduction: Although efficacious in stroke prevention in non-valvular atrial fibrillation (NVAF), many warfarin patients are sub-optimally managed. Out-of-range INR values have been associated with increased risk of thrombosis and bleeding. Little is known about INR control and clinical events in NVAF patients with comorbid diabetes.
Objective: To evaluate the association of INR control and clinical outcomes among new warfarin patients with NVAF and diabetes in the US.
Methods: Adult NVAF patients with diabetes who newly initiated warfarin were selected from the Veterans Health Administration Medical datasets for the duration 10/2007 through 9/2012. Valid INR values (0.5≤INR≤ 20) were examined from the warfarin initiation date through the earlier of first clinical outcome, end of warfarin use, or death. Each patient contributed multiple periods of in-range (2≤INR≤3) and out-of-range (INR<2 or INR>3) values. The relative risk ratios (RRR) of clinical outcomes associated with INR control were estimated.
Results: Of 34,346 NVAF patients, 39.5% (13,577) had baseline diabetes. Table 1 shows the incidence associated with INR<2, 2 to 3, and >3 respectively for the overall and the diabetic populations. Poisson regression showed that INR<2 was significantly associated with increased risk of developing ACS (RRR: 7.0, 95% CI: 5.8-8.5), ischemic stroke (RRR: 6.4, 95% CI: 5.0-8.1), TIA (RRR: 6.0, 95% CI: 3.8-9.4), systemic embolism (RRR: 5.3, 95% CI: 3.1-8.8) and major bleeding (RRR: 2.5, 95% CI: 2.0-3.2). INR>3 was not significantly associated with increased risk of any of the clinical outcomes. Diabetes, despite an indicator of baseline cardiovascular risk, did not contribute to poor INR control. In fact, diabetes was associated with higher percent of time-in-therapeutic range, possibly reflecting more frequent health service encounters.
Conclusions: In NVAF patients with diabetes, INR values of <2 was associated with high risks of adverse clinical outcomes.
Author Disclosures: W.W. Nelson: Employment; Significant; Employee of study sponsor, Janssen Scientific Affairs, LLC. L. Wang: Employment; Significant; Employee of STATinMED Research, a consulting company that has received research grants from Janssen Scientific Affairs, LLC. O. Baser: Employment; Significant; Employee of STATinMED Research, a consulting company that has received research grants from Janssen Scientific Affairs, LLC. C. Damaraju: Employment; Significant; Employee of study sponsor, Janssen Research & Development, LLC. J.R. Schein: Employment; Significant; Employee of study sponsor, Janssen Scientific Affairs, LLC.
- © 2014 by American Heart Association, Inc.