Warfarin Quality Metrics for Hospitalized Older Adults

Abstract

Background Warfarin's adverse drug events are dangerous, common, and costly. While outpatient warfarin management tools exist, there is a dearth of guidance for inpatients.

Objectives We sought to describe a health system's chronic warfarin quality metrics in older inpatients, defined by international normalized ratio (INR) control, explore associations between INR overshoots and clinical outcomes, and identify factors associated with overshoots.

Patients/Methods Data on patients 65 years and older who were prescribed chronic warfarin and admitted during January 1, 2014, to June 30, 2016, were extracted through retrospective chart review. We defined overshoots as INRs 5 or greater after 48 hours of hospitalization. Logistic regression modeling was used to determine risks for overshoots and multivariate analysis for overshoots' association with length of stay (LOS), bleeding, and mortality.

Results Of the 12,107 older inpatients on chronic warfarin, most were 75 years or older (75.7%), female (51.2%), and white (70.0%). While 1,333 (11.0%) of patients had overshoots during the admission, 449 (33.7%) of these reached overshoots after 48 hours. When stratified by overshoots versus no overshoots, LOS more than doubled (15.6 vs. 6.8 days) and the bleed rate was significantly higher (27.4 vs. 8.3%) in the overshoot group. While overall mortality was small (0.4%), the overshoot group's mortality was significantly higher (3.12 vs. 0.28%). Black race and weight were protective against overshoots; history of heart failure and antibiotic/amiodarone exposure were predictive of overshoots.

Conclusion This is the largest study examining warfarin quality metrics for hospitalized adults, specifically older inpatients. Our model may serve as the basis for identifying high-risk warfarin patients to target interventions to reduce adverse drug events.

Keywords

adverse drug events - anticoagulants - inpatients - INR - warfarin

• References

• 1 Wysowski DK, Nourjah P, Swartz L. Bleeding complications with warfarin use: a prevalent adverse effect resulting in regulatory action. Arch Intern Med 2007; 167 (13) 1414-1419
• 2 Classen DC, Jaser L, Budnitz DS. Adverse drug events among hospitalized Medicare patients: epidemiology and national estimates from a new approach to surveillance. Jt Comm J Qual Patient Saf 2010; 36 (01) 12-21
• 3 Winterstein AG, Hatton RC, Gonzalez-Rothi R, Johns TE, Segal R. Identifying clinically significant preventable adverse drug events through a hospital's database of adverse drug reaction reports. Am J Health Syst Pharm 2002; 59 (18) 1742-1749
• 4 Ghate SR, Biskupiak J, Ye X, Kwong WJ, Brixner DI. All-cause and bleeding-related health care costs in warfarin-treated patients with atrial fibrillation. J Manag Care Pharm 2011; 17 (09) 672-684
• 5 Harris Y, Hu DJ, Lee C, Mistry M, York A, Johnson TK. Advancing medication safety: establishing a national action plan for adverse drug event prevention. Jt Comm J Qual Patient Saf 2015; 41 (08) 351-360
• 6 The Joint Commission. National Patient Safety Goals. 03.05.01. Available at: https://www.jointcommission.org/assets/1/6/2017_NPSG_HAP_ER.pdf . Accessed August 28, 2017
• 7 Spyropoulos AC, Viscusi A, Singhal N. , et al. Features of electronic health records necessary for the delivery of optimized anticoagulant therapy: consensus of the EHR Task Force of the New York State Anticoagulation Coalition. Ann Pharmacother 2015; 49 (01) 113-124
• 8 Garcia DA, Schwartz MJ. Warfarin therapy: tips and tools for better control. J Fam Pract 2011; 60 (02) 70-75
• 9 Initiation Warfarin Dosing Protocol. University of North Carolina GIM Anticoagulation Clinic Algorithm; 2001–UNC Center of Excellence in Chronic Illness. [cited 2017 Oct 20]. Available at: https://www.med.unc.edu/im/files/enhanced-care-files/anticoag-files/Initiation%20Warfarin%20Dosing%20Protocol.pdf . Accessed June 27, 2018
• 10 Inpatient Warfarin Guideline [Internet]. University of Wisconsin – UW Health. Warfarin Management – Adult – Inpatient Clinical Practice Guide. [cited 2017 Oct 20]. Available at: https://www.uwhealth.org/files/uwhealth/docs/pdf3/Inpatient_Warfarin_Guideline.pdf . Accessed June 27, 2018
• 11 Hamilton General Warfarin Dosing Nomogram [Internet]. [cited 2017 Oct 20]. Available at: https://static-content.springer.com/esm/art%3A10.1007%2Fs11239-013-0969-x/MediaObjects/11239_2013_969_MOESM1_ESM.pdf . Accessed June 27, 2018
• 12 Van Spall HG, Wallentin L, Yusuf S. , et al. Variation in warfarin dose adjustment practice is responsible for differences in the quality of anticoagulation control between centers and countries: an analysis of patients receiving warfarin in the randomized evaluation of long-term anticoagulation therapy (RE-LY) trial. Circulation 2012; 126 (19) 2309-2316
• 13 Warfarin Management - Adult - Ambulatory Clinical Practice Guideline [Internet]. UW Health; [cited 2017 Aug 28]. Available at: http://www.uwhealth.org/files/uwhealth/docs/pdf2/Ambulatory_Warfarin_Guideline.pdf . Accessed June 27, 2018
• 14 UNMH Anticoagulation Subcommittee. Warfarin Dosing Guideline [Internet]. UNM Hospitals; 2013 [cited 2017 Aug 28]. Available at: http://excellence.acforum.org/sites/default/files/warfarin%20dosing%20guideline%204_5_AB.pdf . Accessed June 27, 2018
• 15 Dawson NL, Porter II IE, Klipa D. , et al. Inpatient warfarin management: pharmacist management using a detailed dosing protocol. J Thromb Thrombolysis 2012; 33 (02) 178-184
• 16 Gouin-Thibault I, Levy C, Pautas E. , et al. Improving anticoagulation control in hospitalized elderly patients on warfarin. J Am Geriatr Soc 2010; 58 (02) 242-247
• 17 Metersky ML, Eldridge N, Wang Y. , et al. Predictors of warfarin-associated adverse events in hospitalized patients: opportunities to prevent patient harm. J Hosp Med 2016; 11 (04) 276-282
• 18 Sharma M, Krishnamurthy M, Snyder R, Mauro J. Reducing Error in Anticoagulant Dosing via Multidisciplinary Team Rounding at Point of Care. Clin Pract [Internet]. 2017 Apr 20 [cited 2017 Aug 28];7(2). Available at: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5406843/ . Accessed June 27, 2018
• 19 Cannegieter SC, Rosendaal FR, Wintzen AR, van der Meer FJ, Vandenbroucke JP, Briët E. Optimal oral anticoagulant therapy in patients with mechanical heart valves. N Engl J Med 1995; 333 (01) 11-17
• 20 Leonard CE, Haynes K, Localio AR. , et al. Diagnostic E-codes for commonly used, narrow therapeutic index medications poorly predict adverse drug events. J Clin Epidemiol 2008; 61 (06) 561-571
• 21 Bond CA, Raehl CL. Pharmacist-provided anticoagulation management in United States hospitals: death rates, length of stay, Medicare charges, bleeding complications, and transfusions. Pharmacotherapy 2004; 24 (08) 953-963
• 22 Kimmel SE, French B, Kasner SE. , et al; COAG Investigators. A pharmacogenetic versus a clinical algorithm for warfarin dosing. N Engl J Med 2013; 369 (24) 2283-2293