Venous thromboembolism (VTE) is a leading

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1 Original Research Venous Thromboembolism Prophylaxis and the Impact of Standardized Guidelines: Is a Computer-Based Approach Enough? Muhammad Bilal Quraishi, MD, Robert Mathew, DO, Alicia Lowes, MD, Chowdry M. Bashir, MD, and Ronald J. Markert, PhD ABSTRACT Objective: To determine the frequency of venous thromboembolism (VTE) prophylaxis and the incidence of VTE before and after the implementation of computer-based prophylaxis guidelines based on the American College of Chest Physicians (ACCP) recommendations. Methods: Using a retrospective chart review, we stratified 1406 Veterans Affairs Medical Center patients with multiple risk factors into 3 risk categories (high, intermediate, and low) and determined the frequency of VTE prophylaxis and the VTE rate before and after the implementation of ACCP guidelines. Results: Before the guidelines were implemented, appropriate VTE prophylaxis was used in 401 of 701 (57.2%) patients. After implementation, appropriate prophylaxis was used in 549 of 705 (77.9%) (P < 0.001). The frequency of VTE before guideline implementation was 1.4% (10 cases) while after implementation the rate was 1.2% (8 cases) (P = 0.54). Conclusion: The implementation of computer-based guidelines improved VTE prophylaxis. Electronic alerts and physician education regarding VTE prevention are needed to improve physician compliance and the appropriate selection of prophylaxis. INTRODUCTION Venous thromboembolism (VTE) is a leading cause of morbidity and mortality among hospitalized patients, accounting for approximately 10% of all in-hospital deaths [1,2]. Mechanial and pharmacological methods for VTE prophlaxis are available. Three large randomized, double-blind, placebo-controlled studies have shown that a once-daily fixed low dose of low-molecular-weight heparin or pentasaccharide lowers the incidence of VTE by almost half and does not increase risk of bleeding (ARTE- MIS, MEDENOX and PREVENT trials) [3 5]. A European trial examined the equivalence of low-molecular-weight heparin and heparin. No significant difference in efficacy or safety was found between the 2 treatments (PRINCE trial). In lower-risk populations, prevention of VTE can be achieved through mechanical means, such as the use of intermittent compression devices or regular ambulation [6]. The American College of Chest Physicians (ACCP) recommends that physicians use risk factors to guide choice of VTE prophylaxis [6]. The primary risk factors for VTE are past medical history, reason for admission, and age. Routine implementation of guidelines has proven difficult despite clear indications and methods for VTE prophylaxis. A study at the Brigham and Women s Hospital showed that 71% of patients who developed an ultrasound-confirmed VTE did not have appropriate VTE prophylaxis [7]. There is increased interest in establishing health care system approaches that would aid the clinician in the timely administration of appropriate VTE prophylaxis. Proposed improvements to practice systems range from standardized order sets to computer-based reminders [8 12]. Various studies have shown an improvement in compliance and outcomes with the introduction of enhanced systems-based practices [8,10]. However, given the cost and complexity of establishing standardized From the Veterans Affairs Medical Center, Dayton, OH, and the Department of Medicine, Wright State University Boonshoft School of Medicine, Dayton, OH. Vol. 18, No. 11 November 2011 JCOM 505

2 VTE Prophylaxis Table 1. VTE Risk Categories High Risk Moderate Risk Low Risk Acute spinal injury Active infection Age > 40 yr Hip/pelvis or leg fracture Cellulitis Ambulatory procedure Major surgery Central venous line Minor procedure Malignancy COPD Mechanical ventilation Oral contraceptive pills Pneumonia Family history of VTE Respiratory failure History of inflammatory bowel disease Sepsis Hypercoaguable state Total knee replacement ICU admission Total hip replacement Immobility > 24 hr Congestive heart failure Stroke Nephrotic syndrome Varicose veins COPD = chronic obstructive pulmonary disease; ICU = intensive care unit. guidelines, changes to existing approaches require significant commitment by the institution. We examined the impact of an intervention that involved the introduction of computerized physician guidelines for VTE prophylaxis on the rate of VTE prophylaxis and in-hospital VTE. We hypothesized that the availability of standardized VTE prevention guidelines at hospital admission would result in ACCP recommended prophylaxis choices and lower rates of VTE. METHODS Setting The study was performed at the Veterans Affairs Medical Center (VAMC) in Dayton, Ohio, which has 500 hospital beds (265 nursing home beds, 120 acute care beds, and 115 domiciliary beds). The medical center provides comprehensive health care services in medicine, surgery, mental health, geriatrics, physical rehabilitation, neurology, oncology, dentistry, and hospice care. Many of the patients at the medical center are at high risk of VTE due to multiple chronic medical problems. Patient Sample Patients admitted to the medical center during June August 2008 (before guideline implementation) and October December 2008 (after guidelines implementation) were included in the study. Patients were excluded from the study if they had a VTE diagnosis on admission, had an absolute contraindication to anticoagulation, were admitted to a non-medical floor, or were hospice patients. Guideline The guideline intervention was to add a VTE prophylaxis tab to the standard medical admission order set. Upon selecting, the physician would see a list of risk factors for VTE categorized by high, moderate, or low risk (Table 1). Upon choosing a risk category, the physician would see a list of absolute and relative contraindications as well as prophylaxis options (Table 2 and Table 3). The physician could choose or refuse VTE prophylaxis without explanation. Measures The proportion of patients receiving appropriate prophylaxis before and after implementation of computerized VTE prophylaxis guidelines and the rates of VTE before and after implementation were the primary outcomes of the study. Data Collection The medical records were reviewed by 3 investigators (MBQ, RM, AL). Patients were classified into risk categories (high risk, moderate risk, or low risk) [6, 13 17] based on the presence of risk factors for VTE (Table 1). Patients at low risk were considered to have 506 JCOM November 2011 Vol. 18, No. 11

3 Original Research Table 2. Absolute and Relative Contraindications to Prophylaxis Absolute Contraindications Spine surgery Active hemorrhage Hemorrhage from severe trauma to head or spine in the last 1 month Relative Contraindications Active intracranial lesion Postop within the last 4 hours Hypertensive urgency or emergency Thrombocytopenia < 75,000 Coagulopathy with INR > 2 End-stage liver disease Intraocular surgery or epidural catheter insertion within the last 2 weeks Gastrointestinal bleed within the last 1 year Genitourinary bleed or craniotomy within the last 1 month appropriate prophylaxis if they received either mechanical prophylaxis in the form of pneumatic compression devices and/or ambulation specified in the nursing orders. Patients at moderate risk were considered appropriate if they received pharmacological prophylaxis or pneumatic compression devices when anticoagulation was contraindicated. Patients at high risk were considered appropriate if they received either (a) pharmacologic prophylaxis alone or in combination with pneumatic compression devices or (b) pneumatic compression devices alone if a contraindication existed. Absolute and relative contraindications are shown in Table 2. Patients who were already on outpatient anticoagulation were considered to have appropriate prophylaxis if the international normalized ratio (INR) was in the therapeutic range of 2 3 upon admission. If the INR was less than 2, prophylaxis had to be administered to be considered as appropriate VTE prophylaxis. To determine incidence of VTE we reviewed the medical records for an International Classification of Diseases, 9th Revision inpatient diagnosis code for VTE as determined by CT scan, lower extremity Doppler scan, or ventilation-perfusion scan. Data Analysis The chi squared test and Fisher s exact test were used to compare groups on categorical variables. The independent samples test was used to compare groups on continuous variables. SPSS version 11.0 (SPSS, Chicago, IL) was used for data analysis. The rate of inpatient VTE at the Dayton VAMC was not known, but surveillance data from other institutions place the VTE rates between 10% and 15%. To determine the sample size, we used alpha and beta error rates of 5% and 20%, respectively and considered a decrease from 15% to 10% in VTE frequency after the ACCP guideline implementation as clinically meaningful. The review, collection, and management of data complied with Health Insurance Portability and Accountability Act (HIPAA) regulations, and the study was approved by the institutional review boards (IRBs) of the VAMC and Wright State University. No software-based audit tools were used. However, data collection was performed twice to reduce variability and enhance accuracy. The IRB committees continued periodic review of the study to ensure compliance. RESULTS There were 701 consecutive patients before the ACCP guidelines were implemented and 705 consecutive patients after the implementation. Table 4 shows their demographic and clinical characteristics. Due to the study s location at a veterans hospital, the sample was predominantly male (> 95% for both groups). Patients were mostly Caucasian (both groups > 75%) or African American (both groups > 23%). The race of 5 patients was not documented. While age was not recorded, few patients admitted at the Dayton VAMC are younger than 40 years of age. The post implementation group had a higher mean BMI (29.41 vs , P = 0.007), and the pre implementation group had a higher mean creatinine level (1.54 vs. 1.40, P = 0.032). Vol. 18, No. 11 November 2011 JCOM 507

4 VTE Prophylaxis Table 3. Forms of Prophylaxis Ambulation Compression devices Enoxaparin 40 mg subcutaneously daily 30 mg subcutaneously daily 1 mg/kg subcutaneously every 12 hours 1 mg/kg subcutaneously daily 1.5 mg/kg subcutaneously daily Heparin drip Heparin 5000 units subcutaneously every 8 hours Heparin 5000 units subcutaneously every 12 hours Warfarin with INR > 2 group was less likely to receive mechanical prophylaxis (16.6% vs. 28.7%) but more likely to receive pharmacologic prophylaxis (63.0% vs. 38.8%, P < 0.001). In addition, the post implementation group received appropriate prophylaxis more frequently (77.9% vs. 57.2%, P < 0.001). There was no statistically significant difference in VTE rate between the 2 groups (P = 0.54) (Table 5). Both groups had 2 patients with a pulmonary embolus. The pre implementation group had 8 patients with a DVT while the post implementation group had 4 patients with a DVT; the post implementation group had 2 patients with both a pulmonary embolism and DVT. Forty (5.7%) patients in the pre implementation group had a history of clot, whereas 42 (6.0%) in the post implementation group had a history of clot (P = 0.84). The groups did not differ in location of the clot (P = 0.83). Thirty-eight patients (95.0%) in the pre implementation group and 41 (95.3%) in the post implementation group were venous in clot location. One patient in the pre implementation group and none in the post implementation group had a history of an arterial clot. One patient in the pre implementation group and 2 patients in the post implementation group had a history of both a venous and arterial clot. Two (0.3%) patients in each group had a family history of clots (P = 1.00). The groups did not differ on outpatient anticoagulation (both with rates of approximately 12%), treatment on admission (both groups > 5%) or history of recent surgery (both groups approximately 1%). The post implementation group was less likely to have a contraindication to anticoagulation (83.4% vs 85.1%, P = 0.028). The 2 groups differed in VTE risk level distribution, but their differences did not follow a linear pattern. The post implementation group had more low-risk patients (22% vs. 14%) and more high-risk patients (33% vs 25.5%) but fewer moderate-risk patients (45% vs. 60%, P < 0.001). Primary Outcomes The post implementation group was more likely to receive prophylaxis than the pre implementation group (mechanical, pharmacologic, or both; 81.8% vs. 71.8%, P < 0.001) (Table 5). Further, the post implementation DISCUSSION VTE continues to play an important role in morbidity and mortality for all patients admitted to acute medical and surgical floors. At the Dayton VAMC we found that even though appropriate prophylaxis according to patient risk category improved after implementation of a standardized system for prophylaxis, no difference in the rates of VTE occurred. The low VTE rate for both the pre and post implementation groups could be due in part to the short hospital stays for our patients (approximately 4 days). Since the sample sizes for the 2 groups in our observational study were substantial, it was not unexpected that some baseline characteristics were statistically significant (ie, BMI, creatinine, and contraindication to anticoagulation). However, the magnitude of these group differences was small (difference of 1 BMI point, 0.14 in creatinine, and 1.7% difference in relative or absolute contraindication) and likely had no clinical impact. Nonetheless, a higher BMI is associated with a greater risk of developing VTE [18]. VTE risk differed by group, but the relationship was not linear; the post implementation group had both more low-risk and more high-risk patients. The risk differences could be due to variation in the time periods for data collection (summer for pre implementation vs. winter for post implementation). Also, the post implementation group was more likely to receive pharmacologic prophylaxis and less likely to receive mechanical prophylaxis. The prophylaxis differences (as well as the VTE risk differences) could be due to the use of a computer-based approach for risk stratification and the subsequent selection of prophylaxis. However, the dif- 508 JCOM November 2011 Vol. 18, No. 11

5 Original Research Table 4. Baseline Characteristics of Patients Before and After Implementation of VTE Guidelines Characteristic Before Implementation After Implementation P Value Patients, n Sex, n 0.59 Male 668 (95.3%) 676 (95.9%) Female 33 (4.7%) 29 (4.1%) Race, n 0.92 Caucasian 524 (75.0%) 530 (75.5%) African American 165 (23.6%) 164 (23.4%) Asian 8 (1.1%) 2 (0.3%) Hispanic 2 (0.3%) 6 (0.9%) BMI, mean ± SD ± ± Creatinine level, mean ± SD 1.54 ± ± History of clot, n 0.84 Yes 40 (5.7%) 42 (6.0%) No 661 (94.3%) 663 (94.0%) Location of clot, n 0.83 Venous 38 (95.0%) 41 (95.3%) Arterial 1 (2.5%) 0 (0%) Both 1 (2.5%) 1 (4.7%) Family history of clot, n 1.00 Yes 2 (0.3%) 2 (0.3%) No 699 (99.7%) 703 (99.7%) Outpatient anticoagulation, n 0.71 Yes 81 (11.6%) 86 (12.2%) No 620 (88.4%) 619 (87.8%) Treatment on admission, n 0.89 Yes 39 (5.6%) 38 (5.4%) No 662 (94.4%) 667 (94.6%) Recent surgery, n 0.28 Yes 9 (1.3%) 5 (0.7%) No 692 (98.7%) 700 (99.3%) Contraindication to anticoagulation, n None 596 (85.1%) 587 (83.4%) Relative 69 (9.9%) 58 (8.2%) Absolute 35 (5.0%) 59 (8.4%) VTE risk, n < Low 99 (14.1%) 155 (22.0%) Intermediate 423 (60.3%) 317 (45.0%) High 179 (25.5%) 232 (33.0%) ferences in VTE risk and prophylaxis had no effect on VTE rates in the study. Our study had limitations. First, two-thirds of the patients were assigned to a risk category by a single observer. Second, the retrospective nature of the study did not allow for identification of post hospitalization VTE events, the time during which most symptomatic VTEs associated with hospital admission occur. Third, the Vol. 18, No. 11 November 2011 JCOM 509

6 VTE Prophylaxis Table 5. Prophylaxis and VTE Rates Before and After Implementation of VTE guidelines Before Implementation After Implementation P Value Prophylaxis type, n < Mechanical 201 (28.7%) 117 (16.6%) Pharmacologic 272 (38.8%) 444 (63.0%) Both 30 (4.3%) 16 (2.3%) None 198 (28.2%) 128 (18.2%) Appropriate prophylaxis, n < Yes 401 (57.2%) 549 (77.9%) No 300 (42.8%) 156 (22.1%) VTE, n 0.54 PE 2 (0.3%) 2 (0.3%) DVT 8 (1.1%) 4 (0.6%) Both 0 2 (0.3%) investigators did not record the age of patients during the data collection stage. However, the study sample included few young patients. Finally, as mentioned earlier, the hospital stay was relatively short (mean, 4 days); consequently, we may have underestimated the VTE rate found in other inpatient settings. The study provided our facility with new and useful information about inpatient VTE rates and the frequency of prophylaxis. Only 18 of 1406 patients (1.3%) in the 2 groups had a pulmonary embolism or DVT. 198 patients (28.2%) received no form of prophylaxis before guideline implementation, and 128 (18.2%) received none after implementation of guidelines. Although we found an improvement in the rate of VTE prophylaxis following the change to computer-based guidelines, the failure to provide prophylaxis to nearly 1 in 5 patients is problematic. This omission raises a number of questions. Why, even after the availability of computer-based risk assessment, did so many patients not receive any form of VTE prophylaxis? While our facility has a computer-based VTE risk assessment and prophylaxis system, there are no alerts or reminders for physicians. Thus, while aware of the presence of the risk assessment and prophylaxis system, physicians may overlook its use and subsequently not provide the appropriate prophylaxis. Perhaps pop-up alerts should be added to remind physicians to perform risk assessment and choose the appropriate VTE prophylaxis for every patient admission. While the percentage of patients receiving inappropriate prophylaxis was reduced by nearly half (from 43% to 22%) in the period following guideline implementation, it is nevertheless alarming that nearly 1 in 5 patients was not receiving appropriate VTE prophylaxis. Apparently, in addition to a computer-based risk assessment and prophylaxis system, an enhanced program of physician education is also necessary. Surgery is believed to be closely related to VTE events. However, 50% to 70% of symptomatic thromboembolic events and 70% to 80% of fatal pulmanry embolisms occur in nonsurgical patients [19 22]. There is an eightfold increase in the relative risk of VTE in patients who are hospitalized for an acute medical illness. The inpatient case fatality rate is close to 12% for those having symptomatic thromboembolic events, and the case fatality rate is between 29% to 34% at 1 year [23,24]. Fortunately, morbidity and mortality associated with VTE can be reduced. In 2008 the Centers for Medicare and Medicaid Services introduced regulations to improve the quality of patient care. One of these is that hospitals will have to pay for conditions that could have been prevented by adhering to evidence-based guidelines. VTE is one of these preventable conditions, and hospitals will have to devise strategies to assure that every admitted patient receives correct risk assessment and prophylaxis. A number of studies have shown that some VTE prophylaxis is inappropriate. In the ENDORSE study, only 39.5% of hospitalized medical patients received appropriate VTE prophylaxis [25]. In another study, 33.9% of hospitalized patients received VTE prophylaxis, of 510 JCOM November 2011 Vol. 18, No. 11

7 Original Research which only 61.8% were determined to be appropriate according to the ACCP guidelines [26]. In an audit of 384 patients who developed an in-hospital DVT or pulmonary embolism after admission to Brigham and Women s Hospital, 52% had received ineffective prophylaxis, and 48% had received no prophylaxis whatsoever [7]. This poor state of VTE risk assessment and subsequent prophylactic selection in the United States likely contributes to the 10% of hospital deaths attributed to pulmonary embolism [6]. Electronic methods (ie, computer-based models) have been shown to be effective tools for accurate risk assessment and appropriate selection of prophylaxis [8,10]. Physician compliance can be enhanced with computerized order entry and reminders in the form of alerts [10]. In our study, even though physician compliance improved, many health care providers failed to choose the prophylaxis appropriate for a patient s risk category. 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