Evaluation of Bleeding Risk in Patients Exposed to Therapeutic UFH or LMWH
Background: Bleeding associated with the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) can be a serious complication of health-care management and should be the focus of quality improvement initiatives by institutions.
Objective: To measure the incidence of bleeding with UFH and LMWH and evaluate associated risk factors.
Methods: An observational cohort study was conducted at a secondary and tertiary care hospital in Canada. All adults receiving therapeutic doses of UFH or LMWH between April 2006 and March 2007, with the exception of cardiac surgery patients, were included. Bleeding episodes were classified per the GUSTO scale.
Results: Of 3066 hospitalizations, the incidence of moderate or severe bleeding was 3.5%. Advanced age (OR 1.02, 95% CI 1.01 to 1.04; p < 0.001), female sex (OR 1.80, 95% CI 1.21 to 2.66; p = 0.003), UFH instead of LMWH (OR 4.72, 95% CI 2.17 to 10.30; p < 0.001), creatinine clearance (CrCl) (OR 0.89, 95% CI 0.84 to 0.95; p < 0.001, for a difference of 10 mL/min in CrCl), and supratherapeutic activated partial thromboplastin time (aPTT) (OR 3.88, 95% CI 2.25 to 6.69; p < 0.001 for >180 vs <90 seconds) were associated with a higher risk of bleeding in univariate analysis. In a multivariate model without aPTT, CrCl (OR 0.90, 95% CI 0.85 to 0.96; p < 0.001, for a difference of 10 mL/min in CrCl) and UFH (OR 2.35, 95% CI 1.11 to 4.98; p = 0.005) were significant predictors of bleeding. Among the bleeding episodes, 31% were in a postoperative context and 15% were following a puncture.
Conclusions: Our findings show that CrCl and aPTT values, as well as the type of heparin used, are significant predictors of bleeding in patients receiving UFH or LMWH and that dosages should be adjusted to patient weight. The reason for all supratherapeutic aPTT levels should be sought and corrective measures taken immediately.
Medications are the second most important cause of adverse events (AEs) related to health-care management. According to the Harvard Medical Practice Study, an AE related to health-care management occurs in 3.7% of hospitalizations and medications account for 19.4% of AEs. A Canadian study demonstrated that unintended injuries or complications occurred in 7.5% of hospitalizations and that 36.9% of AEs were avoidable. The most common types of AE were related to surgical procedures (34.1%) and medications (23.6%). Studies assessing the drug classes responsible for AEs ranked anticoagulants between third and sixth in importance. Bleeding is the main AE associated with anticoagulant use. In the 2008 antithrombotic and thrombolytic therapy guidelines of the American College of Chest Physicians (ACCP), the authors estimated that the incremental risk of major hemorrhage with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH), when compared to placebo or other therapies, could be as high as 2%.
UFH and LMWH are on the List of High-Alert Medications issued by the Institute for Safe Medication Practices. The Joint Commission included a new requirement (03.05.01) in National Patient Safety Goals for Hospitals for 2008, namely: "Reduce the likelihood of patient harm associated with the use of anticoagulation therapy." Given the risk of AEs associated with the use and common prescription of UFH and LMWH in our institution, many measures have been and will be initiated, with an objective of improving quality of care to ensure their safest use possible. We report the results of one of these measures, a cohort study conducted to determine the overall incidence of bleeding related to these medications in actual clinical practice and to evaluate the impact of certain variables on the incidence of bleeding.
Abstract and Introduction
Abstract
Background: Bleeding associated with the use of unfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) can be a serious complication of health-care management and should be the focus of quality improvement initiatives by institutions.
Objective: To measure the incidence of bleeding with UFH and LMWH and evaluate associated risk factors.
Methods: An observational cohort study was conducted at a secondary and tertiary care hospital in Canada. All adults receiving therapeutic doses of UFH or LMWH between April 2006 and March 2007, with the exception of cardiac surgery patients, were included. Bleeding episodes were classified per the GUSTO scale.
Results: Of 3066 hospitalizations, the incidence of moderate or severe bleeding was 3.5%. Advanced age (OR 1.02, 95% CI 1.01 to 1.04; p < 0.001), female sex (OR 1.80, 95% CI 1.21 to 2.66; p = 0.003), UFH instead of LMWH (OR 4.72, 95% CI 2.17 to 10.30; p < 0.001), creatinine clearance (CrCl) (OR 0.89, 95% CI 0.84 to 0.95; p < 0.001, for a difference of 10 mL/min in CrCl), and supratherapeutic activated partial thromboplastin time (aPTT) (OR 3.88, 95% CI 2.25 to 6.69; p < 0.001 for >180 vs <90 seconds) were associated with a higher risk of bleeding in univariate analysis. In a multivariate model without aPTT, CrCl (OR 0.90, 95% CI 0.85 to 0.96; p < 0.001, for a difference of 10 mL/min in CrCl) and UFH (OR 2.35, 95% CI 1.11 to 4.98; p = 0.005) were significant predictors of bleeding. Among the bleeding episodes, 31% were in a postoperative context and 15% were following a puncture.
Conclusions: Our findings show that CrCl and aPTT values, as well as the type of heparin used, are significant predictors of bleeding in patients receiving UFH or LMWH and that dosages should be adjusted to patient weight. The reason for all supratherapeutic aPTT levels should be sought and corrective measures taken immediately.
Introduction
Medications are the second most important cause of adverse events (AEs) related to health-care management. According to the Harvard Medical Practice Study, an AE related to health-care management occurs in 3.7% of hospitalizations and medications account for 19.4% of AEs. A Canadian study demonstrated that unintended injuries or complications occurred in 7.5% of hospitalizations and that 36.9% of AEs were avoidable. The most common types of AE were related to surgical procedures (34.1%) and medications (23.6%). Studies assessing the drug classes responsible for AEs ranked anticoagulants between third and sixth in importance. Bleeding is the main AE associated with anticoagulant use. In the 2008 antithrombotic and thrombolytic therapy guidelines of the American College of Chest Physicians (ACCP), the authors estimated that the incremental risk of major hemorrhage with unfractionated heparin (UFH) or low-molecular-weight heparin (LMWH), when compared to placebo or other therapies, could be as high as 2%.
UFH and LMWH are on the List of High-Alert Medications issued by the Institute for Safe Medication Practices. The Joint Commission included a new requirement (03.05.01) in National Patient Safety Goals for Hospitals for 2008, namely: "Reduce the likelihood of patient harm associated with the use of anticoagulation therapy." Given the risk of AEs associated with the use and common prescription of UFH and LMWH in our institution, many measures have been and will be initiated, with an objective of improving quality of care to ensure their safest use possible. We report the results of one of these measures, a cohort study conducted to determine the overall incidence of bleeding related to these medications in actual clinical practice and to evaluate the impact of certain variables on the incidence of bleeding.
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