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IIR 10-374 – HSR Study

IIR 10-374
Patient-Level Determinants of Oral Anticoagulation Control in the VHA
Adam J Rose, MD MSc
VA Bedford HealthCare System, Bedford, MA
Bedford, MA
Funding Period: January 2011 - December 2013
Over 100,000 VHA patients receive oral anticoagulation therapy (OAT) each year. It is known that OAT is safer and more effective when patients spend more time in the therapeutic range (TTR). However, VHA sites of care vary widely on TTR, from 70% time in range (excellent control) to below 40% (poor control). Our previous efforts to adjust TTR for case mix have had certain limitations, and we need to know more about what sites might do to improve their TTR.

1) Improve our risk adjustment model for TTR. 2) Study the relationship between site-level processes of care and site-level performance on risk-adjusted TTR (RA-TTR). 3) Develop and pilot a tool to report each site's performance and opportunities for improvement.

We included all patients who received OAT from the VHA during the study period. We computed TTR for each patient and mean TTR for each site of care.
Aim 1) We improved our risk adjustment model by adding severity levels to comorbid conditions that impact TTR.
Aim 2) We studied the impact of four process of care measures on site-level anticoagulation control. Two of these measures relate to the site mean follow-up interval after a low (/= 4.0) INR (international normalized ratio) value. Another measure relates to the proportion of patients at each site with a mean INR value between 2.3-2.7, which is reflective of the use of a gudeline-concordant target INR range. The final measure relates to the rate of 56 day "gaps" in monitoring, or periods when patients are in possession of warfarin but not receiving INR testing.
Aim 3) We modified an existing SQL-based "Dashboard" to track these four process measures, and used it to profile site-level TTR and site-level process of care measures over time in VISN 1. End user feedback regarding the measurement system was solicited and incorporated.

With regard to the first aim, we finished our work in severity stratification for the most important clinical conditions that impact anticoagulation control. We examined how the severity of these conditions can impact anticoagulation control (TTR), major hemorrhage, and in some cases rates of ischemic stroke. Conditions we examined include chronic liver disease, dementia, mental illnesses, alcohol and non-alcohol substance abuse, congestive heart failure (CHF), and cancer.

We developed a composite severity score for CHF that works very well to risk-stratify patients on outcomes, based upon such factors as serum sodium, AST, a history of heart failure admissions, and use of certain medications (e.g., metolazone). Our composite severity score for patients with liver disease is based upon factors such as albumin level and creatinine level, which is important because little is currently understood about which patients with liver disease can safely receive warfarin. We noted that while patients with substance abuse have poor outcomes as a group, among patients with alcohol abuse, the AST/ALT ratio (aspartate aminotransferase / alanine aminotransferase) is extremely useful to risk-stratify with regard to predicting outcomes. In fact, patients with a normal AST/ALT ratio have similar outcomes to the general population of warfarin users, an important and reassuring finding. In general, most patients with mental illness have similar outcomes to the general population when using warfarin, especially after accounting for covariates.

With regard to the second aim, we developed four site-level process of care measures: mean follow-up interval after low INR; mean follow-up interval after high INR; rate of 56-day gaps in INR testing per patient-year; and proportion of patients with a mean INR value 2.3-2.7. Together, these 4 process measures have an R2 of 0.48 to predict site-level percent time in therapeutic range.

With regard to the third aim, we deployed these four process measures as part of a Dashboard in VISN 1 (Veterans Integrated Service Network 1). This Dashboard has been instrumental in helping to drive quality improvement in VISN 1 in this area. It has also served as a basis for another project to continue our QI work in anticoagulation.

Our 4 process of care measures for anticoagulation care, developed through this project, have become the basis of our effort to improve anticoagulation control in VISN 1 (SDP 12-249). Incorporating these measures into a SQL dashboard has enabled public reporting and ongoing quality improvement efforts. These measures have been well-received. Anticoagulation control (TTR) has already improved in VISN 1 from 63% to 66%, a meaningful change. This improvement has been correlated with improvements in the process of care measures. We are working to incorporate these process measures, developed through this project, as part of a national Anticoagulation Dashboard for the entire VHA.

Our work on risk-stratifying specific clinical conditions has contributed important insights that can help inform clinical practice.

Little had been known about warfarin use in patients who abuse alcohol, and clincians had been profoundly uncomfortable with the lack of information. We have identified the AST/ALT ratio as being able to risk-stratify these patients and to identify a sizeable subset whose outcomes are similar to the population at large.

Similarly, there has been no information about the use of warfarin in patients with liver disease. Our study (paper submitted) has demonstrated that two commonly measured lab tests (albumin and creatinine) can risk-stratify these patients, and can again identify a sizeable subset whose outcomes are similar to the population at large.

Our work on patients with mental illness has confirmed that most such patients can use warfarin with similar results to the general population.

Our work with CHF patients has demonstrated that easily available information can risk-stratify patients in a way that predicts TTR and also adverse events.

External Links for this Project

NIH Reporter

Grant Number: I01HX000542-01

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Journal Articles

  1. Rothendler JA, Rose AJ, Reisman JI, Berlowitz DR, Kazis LE. Choices in the use of ICD-9 codes to identify stroke risk factors can affect the apparent population-level risk factor prevalence and distribution of CHADS2 scores. American journal of cardiovascular disease. 2012 Jul 25; 2(3):184-91. [view]
  2. Cancino RS, Hylek EM, Reisman JI, Rose AJ. Comparing patient-level and site-level anticoagulation control as predictors of adverse events. Thrombosis research. 2014 Apr 1; 133(4):652-6. [view]
  3. Rose AJ, Miller DR, Ozonoff A, Berlowitz DR, Ash AS, Zhao S, Reisman JI, Hylek EM. Gaps in monitoring during oral anticoagulation: insights into care transitions, monitoring barriers, and medication nonadherence. Chest. 2013 Mar 1; 143(3):751-7. [view]
  4. Jasuja GK, Reisman JI, Miller DR, Berlowitz DR, Hylek EM, Ash AS, Ozonoff A, Zhao S, Rose AJ. Identifying major hemorrhage with automated data: results of the Veterans Affairs study to improve anticoagulation (VARIA). Thrombosis research. 2013 Jan 1; 131(1):31-6. [view]
  5. Efird LM, Miller DR, Ash AS, Berlowitz DR, Ozonoff A, Zhao S, Reisman JI, Jasuja GK, Rose AJ. Identifying the risks of anticoagulation in patients with substance abuse. Journal of general internal medicine. 2013 Oct 1; 28(10):1333-9. [view]
  6. Razouki Z, Ozonoff A, Zhao S, Jasuja GK, Rose AJ. Improving quality measurement for anticoagulation: adding international normalized ratio variability to percent time in therapeutic range. Circulation. Cardiovascular quality and outcomes. 2014 Sep 1; 7(5):664-9. [view]
  7. Rose AJ, Berlowitz DR, Miller DR, Hylek EM, Ozonoff A, Zhao S, Reisman JI, Ash AS. INR targets and site-level anticoagulation control: results from the Veterans AffaiRs Study to Improve Anticoagulation (VARIA). Journal of Thrombosis and Haemostasis : Jth. 2012 Apr 1; 10(4):590-5. [view]
  8. Paradise HT, Berlowitz DR, Ozonoff A, Miller DR, Hylek EM, Ash AS, Jasuja GK, Zhao S, Reisman JI, Rose AJ. Outcomes of anticoagulation therapy in patients with mental health conditions. Journal of general internal medicine. 2014 Jun 1; 29(6):855-61. [view]
  9. Razouki Z, Ozonoff A, Zhao S, Rose AJ. Pathways to poor anticoagulation control. Journal of Thrombosis and Haemostasis : Jth. 2014 May 1; 12(5):628-34. [view]
  10. Kim EJ, Ozonoff A, Hylek EM, Berlowitz DR, Ash AS, Miller DR, Zhao S, Reisman JI, Jasuja GK, Rose AJ. Predicting outcomes among patients with atrial fibrillation and heart failure receiving anticoagulation with warfarin. Thrombosis and Haemostasis. 2015 Jul 1; 114(1):70-7. [view]
  11. Rose AJ, Hylek EM, Berlowitz DR, Ash AS, Reisman JI, Ozonoff A. Prompt repeat testing after out-of-range INR values: a quality indicator for anticoagulation care. Circulation. Cardiovascular quality and outcomes. 2011 May 1; 4(3):276-82. [view]
  12. Rose AJ, Hylek EM, Ozonoff A, Ash AS, Reisman JI, Callahan PP, Gordon MM, Berlowitz DR. Relevance of current guidelines for organizing an anticoagulation clinic. The American journal of managed care. 2011 Apr 1; 17(4):284-9. [view]
  13. Efird LM, Mishkin DS, Berlowitz DR, Ash AS, Hylek EM, Ozonoff A, Reisman JI, Zhao S, Jasuja GK, Rose AJ. Stratifying the risks of oral anticoagulation in patients with liver disease. Circulation. Cardiovascular quality and outcomes. 2014 May 13; 7(3):461-7. [view]
  14. Rose AJ, Berlowitz DR, Ash AS, Ozonoff A, Hylek EM, Goldhaber-Fiebert JD. The business case for quality improvement: oral anticoagulation for atrial fibrillation. Circulation. Cardiovascular quality and outcomes. 2011 Jul 1; 4(4):416-24. [view]
  15. Ambrus DB, Reisman JI, Rose AJ. The impact of new-onset cancer among veterans who are receiving warfarin for atrial fibrillation and venous thromboembolism. Thrombosis research. 2016 Aug 1; 144:21-6. [view]
  16. Jasuja GK, Bhasin S, Rose AJ, Reisman JI, Skolnik A, Berlowitz DR, Gifford AL. Use of testosterone in men infected with human immunodeficiency virus in the veterans healthcare system. AIDS Care. 2018 Oct 1; 30(10):1207-1214. [view]
Journal Other

  1. Rose AJ. Improving the management of warfarin may be easier than we think. Circulation. 2012 Nov 6; 126(19):2277-9. [view]
Conference Presentations

  1. Razouki Z, Rose AJ. A new perspective in anticoagulation: Understanding time spent above and below the target range among patients receiving warfarin at the VA health care system. Poster session presented at: Society of General Internal Medicine Annual Meeting; 2013 Apr 24; Denver, CO. [view]
  2. Efird L, Rose AJ. Identifying the risks of anticoagulation in patients with substance abuse. Poster session presented at: Society of General Internal Medicine Annual Meeting; 2013 Apr 24; Denver, CO. [view]
  3. Kim EJ, Rose AJ. Predicting Outcomes among Patients with Heart Failure Receiving Anticoagulation with Warfarin. Paper presented at: American Heart Association Quality of Care and Outcomes Research Council Annual Scientific Session; 2013 May 15; Baltimore, MD. [view]

DRA: Health Systems, Cardiovascular Disease
DRE: Treatment - Observational
Keywords: none
MeSH Terms: none

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