Patient Care

Close INR Monitoring Might Prevent Adverse Events


Clinical question: What is the appropriate frequency of INR monitoring in the hospital and its relationship to the risk of over-anticoagulation and warfarin-related adverse events?

Background: Warfarin use is a common cause of adverse drug events in hospitalized patients due to narrow therapeutic windows, drug interactions, and variability of metabolism. Current guidelines, including those by the American College of Chest Physicians, do not provide recommendations on how often to monitor INR or adjust warfarin dosing in the hospital.

Study design: Retrospective cohort.

Setting: Hospitalized patients included in the Medicare Patient Safety Monitoring System.

Synopsis: The study included 14,217 adult patients ≥18 years of age from the Medicare Patient Safety Monitoring System admitted from 2009 to 2013 with pneumonia, acute cardiac disease (myocardial infarction or congestive heart failure), or surgery and taking warfarin. Of those, 1,055 (7.4%) developed a warfarin-associated adverse event (bleeding, drop in hematocrit ≥3, hematoma, death, intracranial bleeding, or cardiac arrest). Patients admitted for acute cardiac disease (acute myocardial infarction or heart failure) or surgery on warfarin for ≥3 days but not monitored for ≥2 days had more warfarin-associated adverse events (OR 1.48; 95% CI, 1.02–2.17), but this association was not true in pneumonia patients. Cardiac and pneumonia patients with ≥1 day without INR being measured had higher rates of INR ≥6.0 (OR 1.61; 95% CI, 1.07–2.41, and OR 1.92, 95% CI, 1.36–2.71, respectively). A single-day rise in INR ≥0.9 had a likelihood ratio of 4.2 in predicting subsequent INR ≥6.0.

Bottom line: Frequent monitoring of INR may decrease warfarin-associated adverse events in hospitalized patients.

Citation: Metersky ML, Eldridge N, Wang Y, et al. Predictors of warfarin-associated adverse events in hospitalized patients: opportunities to prevent harm. J Hosp Med. 2016;11(4):276-282.

Short Take

CDC Guidelines on Prescribing Opioids

New CDC guidelines for chronic pain management stress the importance of non-pharmacologic (physical therapy, etc.) and non-opioid therapy (NSAIDs, etc.), using opioid therapy only if the expected benefits outweigh the risks.

Citation: CDC. CDC guideline for prescribing opioids for chronic pain. Available at: Published March 16, 2016. Accessed April 8, 2016.

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