Matthew A. Berger, MD

Over 900,000 incident and recurrent venous thromboembolism (VTE) events occur in the United States each year, resulting in nearly 300,000 fatalities.[1] VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE), is among the most common causes of death in the United States, with more people dying annually from VTE than motor vehicle accidents and breast cancer.[2]

Accordingly, healthcare policy makers and regulators have placed greater emphasis on VTE prevention, including use of VTE prophylaxis measures in the Centers for Medicare and Medicaid Services (CMS) value‐based purchasing (pay for performance) program and the Joint Commission's adoption of a national hospital patient safety goal related to anticoagulation therapy.[3, 4] Beginning in 2008, VTE events following hip and knee procedures were included as 1 of 10 hospital‐acquired conditions for which CMS would not pay for associated additional costs of care.[5]

A typical 300‐bed hospital can expect roughly 150 cases of hospital‐acquired VTE annually.[6] Up to 75% of these cases will occur on the medicine service, where nearly every patient has 1 or more VTE risk factor.[7] Although effective preventive modalities exist, prophylaxis rates among medical patients have been noted to be <50%.[8, 9] While quality improvement interventions have been shown to be effective in improving compliance with VTE prophylaxis, there are few studies describing effectiveness of these interventions in electronic health record (EHR) environments.[10] As EHR implementation accelerates, it will be essential to define the strengths and limitations of various decision support approaches to optimally improve patient safety.

We sought to evaluate the effectiveness and safety of a computerized decision support application, which was designed as part of a quality improvement initiative to improve rates of VTE prophylaxis rates on the medicine services at 2 hospital sites.

METHODS

RESULTS

Table 1 compares the effectiveness of the decision support module intervention in medicine intervention and in nonmedicine (nonintervention) services. Among medicine service patients, any VTE prophylaxis ordering increased from 61.9% to 82.1% (P < 0.001), and pharmacologic VTE prophylaxis increased from 59.0% to 74.5% (P < 0.001). Smaller but significant increases were observed on nonmedicine services. Hospital‐acquired VTE incidence on medicine services decreased significantly, from 0.65% to 0.42% (P = 0.008) and nonsignificantly on nonmedicine services.

Table 2 shows ordering patterns for major VTE prophylaxis modalities. Among eligible medicine service patients, rates of low molecular weight heparin prophylaxis increased from 13.0% to 23.7% (P < 0.001), and of unfractionated heparin prophylaxis from 35.1% to 40.7% (P < 0.001). On nonmedicine services, there was no significant change in low molecular weight heparin use, and unfractionated heparin use increased significantly from 37.2% to 40.9% (P < 0.001). Proportions of patients receiving mechanical prophylaxis or not receiving prophylaxis decreased significantly by 37.8% on medicine services and by 9.8% on nonmedicine services Table 3 shows the safety of the decision support module. Bleeding rates increased on medicine services from 2.9% to 4.0% (P < 0.001) and on nonmedicine services from 7.7% to 8.6% (P = 0.043). Nonsignificant changes in thrombocytopenia rates were observed on both services.

DISCUSSION

Following implementation of a computerized decision support application to improve VTE prophylaxis on 2 hospital medicine services, we observed a significant increase in the rate of overall and pharmacologic VTE prophylaxis use and a significant decrease in the incidence of hospital‐acquired VTE. Changes were of greater magnitude and significance on medicine services where the intervention was deployed.

Rates of any VTE prophylaxis and pharmacologic VTE prophylaxis ordering on medicine services increased significantly by 32.7% and 26.3%, respectively. These rates increased on nonmedicine comparison services by a more modest 4.4% for any VTE prophylaxis and 6.7% for pharmacologic VTE prophylaxis. Although the medicine service intervention was designed to be agnostic to the type of prophylactic heparin preparation, the intervention resulted in a significant 82.4% increase in low molecular weight heparin use and a significant 16.0% increase in unfractionated heparin use. With respect to outcomes, we observed a 34.5% decrease (P < 0.001) in hospital‐acquired VTE incidence on medicine services and a nonsignificant decrease on nonmedicine services.

In assessing intervention safety, increased usage of VTE prophylaxis was not accompanied by an increase in thrombocytopenia, but was associated with an increase in bleeding from 2.9% to 4.0% (P < 0.001) on medicine services and from 7.7% to 8.6% (P = 0.043) on non‐medicine services. As our intervention was a quality improvement project, we conducted a brief post hoc analysis to evaluate the increased bleeding rate on the medicine service following intervention. A random sample of 50 records of medicine patients who had received VTE prophylaxis and had a subsequent bleeding event was reviewed. Findings are summarized in Table 4. Prophylaxis was used appropriately in 100% of cases. Bleeding episodes were minor in that no case required more than 2 U of packed red blood cells. The most common clinical scenario was a patient with baseline anemia, typically with chronic kidney disease, who had a slight decrease in hematocrit of unclear etiology requiring 1 U of blood.

Although the intervention occurred on medicine services, favorable albeit smaller changes were observed on nonmedicine services. We expected this favorable secular trend because of VTE prophylaxis awareness efforts across the organization as a whole. There was also ongoing focus on VTE prevention and outcomes by policymakers, regulatory agencies, and professional societies during the time period of study.[3, 4, 5, 12] Public reporting of CMS inpatient surgical VTE prophylaxis measures was required throughout the study period.[13] Changes observed on medicine services occurred during a period where there were no publicly reported measures of VTE prophylaxis for inpatient medicine services.

Our study had several limitations. We derived our eligibility criteria for VTE prophylaxis based on administrative data. To address this, we incorporated accepted standardized definitions,[11] used clinical data elements in our queries beyond ICD‐9 codes (eg, platelet count), and applied pertinent exclusion criteria (eg, length of stay 1 day or less). VTE events that were present on admission were excluded from analyses. However, as these community‐acquired VTE events may be caused by inadequate VTE prophylaxis during a prior hospitalization, the overall true incidence of hospital‐acquired VTE was likely underestimated.

With respect to the hospital‐acquired VTE outcome, we did not distinguish superficial from deep VTE. A consistent AHRQ definition of 13 ICD‐9 VTE codes was used to identify clinically significant VTE events for the periods before and after the intervention. Although the present on admission code identified VTE events that were hospital acquired, 1 new acute VTE ICD‐9 code was added in October 2009, allowing for more specific coding of acute, isolated, upper extremity VTE. Accordingly, our postintervention hospital‐acquired VTE rate may have slightly underestimated the true hospital‐acquired VTE incidence by omitting some coded acute, isolated, upper extremity VTE cases (if not coded using the prior Other VTE codes). In a study in a teaching hospital setting, isolated upper extremity VTE accounted for up to 21% of all symptomatic VTE events among adults.[14]

With respect to VTE prophylaxis, the study evaluated use in a dichotomous fashion but did not assess appropriateness, or adequacy of dosing of pharmacologic agents. We did not employ the intervention in a randomized fashion on the medicine service. As our project was a quality improvement intervention, we used a concurrent control group of nonmedicine service patients to assess potential secular trend bias.

With respect to the safety of the intervention, the record review we performed supported the appropriateness of prophylaxis use following the intervention, but was not designed to establish whether the increase in prophylaxis use was the proximate cause of bleeding events observed. Similarly, as specific testing for heparin‐induced thrombocytopenia was not used, the lack of significant change in thrombocytopenia rates before and after the intervention cannot directly establish the intervention's safety. Finally, our study also included only in‐hospital end points.

The rate of VTE prophylaxis use in hospitals has been noted to be disappointing.[15] Two large multinational studies found that VTE prophylaxis rates in at‐risk hospitalized medical patients in the United States were 48% and 52%.[9, 16] Amin and colleagues found the overall rate of VTE prophylaxis among 227 US hospitals to be 62%.[17] Accordingly, our intervention, which resulted in an 82% compliance rate on a large medical service and was associated with a significantly reduced VTE incidence, appears to be highly effective. Our results are likely more favorable in that beyond length of stay criteria, we did not exclude less acutely ill medical patients from analyses.

Michota summarized quality improvement studies for VTE prevention.[10] Among 9 studies attempting to improve VTE prophylaxis, 2 used electronic decision support as a primary strategy, and only 1, by Kucher et al., used a computerized approach on a medical service.[18] This study showed significant improvement in VTE prophylaxis and incidence in patients randomized to a provider computer program. The intervention was complex, requiring specification of 8 patient‐level risk factors via a customized database, and the physician to recommend specific prophylactic regimens accordingly. Our findings, using a more basic approach, similarly support the effectiveness of using automated decision support, which can be readily modified as evidence‐based guidelines evolve.

Overall adoption of information technology systems in US hospitals is low: only 7.6% of hospitals have a basic system, and 17% have computerized physician order entry.[19] As hospitals have been financially incentivized to adopt such systems, our relatively simple intervention may prove to be readily generalizable across varied vendor systems.[20] The intervention involved order sets triggered by automated logic, corollary information, and a hard stop to prompt VTE prophylaxis. Within the context of intensified emphasis on reducing harm in the inpatient setting and various pay for performance programs, our intervention is also of importance to payers.[3, 5] Using national data in year 2000, Zhan and Miller calculated the excess charges per case associated with VTE to be $21,709.[21]

In conclusion, a relatively simple automated clinical decision support application significantly improved rates of VTE prophylaxis and was associated with significantly lower hospital‐acquired VTE incidence in hospitalized medicine patients, with a reasonable safety profile.

Over 900,000 incident and recurrent venous thromboembolism (VTE) events occur in the United States each year, resulting in nearly 300,000 fatalities.[1] VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE), is among the most common causes of death in the United States, with more people dying annually from VTE than motor vehicle accidents and breast cancer.[2]

Accordingly, healthcare policy makers and regulators have placed greater emphasis on VTE prevention, including use of VTE prophylaxis measures in the Centers for Medicare and Medicaid Services (CMS) value‐based purchasing (pay for performance) program and the Joint Commission's adoption of a national hospital patient safety goal related to anticoagulation therapy.[3, 4] Beginning in 2008, VTE events following hip and knee procedures were included as 1 of 10 hospital‐acquired conditions for which CMS would not pay for associated additional costs of care.[5]

A typical 300‐bed hospital can expect roughly 150 cases of hospital‐acquired VTE annually.[6] Up to 75% of these cases will occur on the medicine service, where nearly every patient has 1 or more VTE risk factor.[7] Although effective preventive modalities exist, prophylaxis rates among medical patients have been noted to be <50%.[8, 9] While quality improvement interventions have been shown to be effective in improving compliance with VTE prophylaxis, there are few studies describing effectiveness of these interventions in electronic health record (EHR) environments.[10] As EHR implementation accelerates, it will be essential to define the strengths and limitations of various decision support approaches to optimally improve patient safety.

We sought to evaluate the effectiveness and safety of a computerized decision support application, which was designed as part of a quality improvement initiative to improve rates of VTE prophylaxis rates on the medicine services at 2 hospital sites.

METHODS

RESULTS

Table 1 compares the effectiveness of the decision support module intervention in medicine intervention and in nonmedicine (nonintervention) services. Among medicine service patients, any VTE prophylaxis ordering increased from 61.9% to 82.1% (P < 0.001), and pharmacologic VTE prophylaxis increased from 59.0% to 74.5% (P < 0.001). Smaller but significant increases were observed on nonmedicine services. Hospital‐acquired VTE incidence on medicine services decreased significantly, from 0.65% to 0.42% (P = 0.008) and nonsignificantly on nonmedicine services.

Table 2 shows ordering patterns for major VTE prophylaxis modalities. Among eligible medicine service patients, rates of low molecular weight heparin prophylaxis increased from 13.0% to 23.7% (P < 0.001), and of unfractionated heparin prophylaxis from 35.1% to 40.7% (P < 0.001). On nonmedicine services, there was no significant change in low molecular weight heparin use, and unfractionated heparin use increased significantly from 37.2% to 40.9% (P < 0.001). Proportions of patients receiving mechanical prophylaxis or not receiving prophylaxis decreased significantly by 37.8% on medicine services and by 9.8% on nonmedicine services Table 3 shows the safety of the decision support module. Bleeding rates increased on medicine services from 2.9% to 4.0% (P < 0.001) and on nonmedicine services from 7.7% to 8.6% (P = 0.043). Nonsignificant changes in thrombocytopenia rates were observed on both services.

DISCUSSION

Following implementation of a computerized decision support application to improve VTE prophylaxis on 2 hospital medicine services, we observed a significant increase in the rate of overall and pharmacologic VTE prophylaxis use and a significant decrease in the incidence of hospital‐acquired VTE. Changes were of greater magnitude and significance on medicine services where the intervention was deployed.

Rates of any VTE prophylaxis and pharmacologic VTE prophylaxis ordering on medicine services increased significantly by 32.7% and 26.3%, respectively. These rates increased on nonmedicine comparison services by a more modest 4.4% for any VTE prophylaxis and 6.7% for pharmacologic VTE prophylaxis. Although the medicine service intervention was designed to be agnostic to the type of prophylactic heparin preparation, the intervention resulted in a significant 82.4% increase in low molecular weight heparin use and a significant 16.0% increase in unfractionated heparin use. With respect to outcomes, we observed a 34.5% decrease (P < 0.001) in hospital‐acquired VTE incidence on medicine services and a nonsignificant decrease on nonmedicine services.

In assessing intervention safety, increased usage of VTE prophylaxis was not accompanied by an increase in thrombocytopenia, but was associated with an increase in bleeding from 2.9% to 4.0% (P < 0.001) on medicine services and from 7.7% to 8.6% (P = 0.043) on non‐medicine services. As our intervention was a quality improvement project, we conducted a brief post hoc analysis to evaluate the increased bleeding rate on the medicine service following intervention. A random sample of 50 records of medicine patients who had received VTE prophylaxis and had a subsequent bleeding event was reviewed. Findings are summarized in Table 4. Prophylaxis was used appropriately in 100% of cases. Bleeding episodes were minor in that no case required more than 2 U of packed red blood cells. The most common clinical scenario was a patient with baseline anemia, typically with chronic kidney disease, who had a slight decrease in hematocrit of unclear etiology requiring 1 U of blood.

Although the intervention occurred on medicine services, favorable albeit smaller changes were observed on nonmedicine services. We expected this favorable secular trend because of VTE prophylaxis awareness efforts across the organization as a whole. There was also ongoing focus on VTE prevention and outcomes by policymakers, regulatory agencies, and professional societies during the time period of study.[3, 4, 5, 12] Public reporting of CMS inpatient surgical VTE prophylaxis measures was required throughout the study period.[13] Changes observed on medicine services occurred during a period where there were no publicly reported measures of VTE prophylaxis for inpatient medicine services.

Our study had several limitations. We derived our eligibility criteria for VTE prophylaxis based on administrative data. To address this, we incorporated accepted standardized definitions,[11] used clinical data elements in our queries beyond ICD‐9 codes (eg, platelet count), and applied pertinent exclusion criteria (eg, length of stay 1 day or less). VTE events that were present on admission were excluded from analyses. However, as these community‐acquired VTE events may be caused by inadequate VTE prophylaxis during a prior hospitalization, the overall true incidence of hospital‐acquired VTE was likely underestimated.

With respect to the hospital‐acquired VTE outcome, we did not distinguish superficial from deep VTE. A consistent AHRQ definition of 13 ICD‐9 VTE codes was used to identify clinically significant VTE events for the periods before and after the intervention. Although the present on admission code identified VTE events that were hospital acquired, 1 new acute VTE ICD‐9 code was added in October 2009, allowing for more specific coding of acute, isolated, upper extremity VTE. Accordingly, our postintervention hospital‐acquired VTE rate may have slightly underestimated the true hospital‐acquired VTE incidence by omitting some coded acute, isolated, upper extremity VTE cases (if not coded using the prior Other VTE codes). In a study in a teaching hospital setting, isolated upper extremity VTE accounted for up to 21% of all symptomatic VTE events among adults.[14]

With respect to VTE prophylaxis, the study evaluated use in a dichotomous fashion but did not assess appropriateness, or adequacy of dosing of pharmacologic agents. We did not employ the intervention in a randomized fashion on the medicine service. As our project was a quality improvement intervention, we used a concurrent control group of nonmedicine service patients to assess potential secular trend bias.

With respect to the safety of the intervention, the record review we performed supported the appropriateness of prophylaxis use following the intervention, but was not designed to establish whether the increase in prophylaxis use was the proximate cause of bleeding events observed. Similarly, as specific testing for heparin‐induced thrombocytopenia was not used, the lack of significant change in thrombocytopenia rates before and after the intervention cannot directly establish the intervention's safety. Finally, our study also included only in‐hospital end points.

The rate of VTE prophylaxis use in hospitals has been noted to be disappointing.[15] Two large multinational studies found that VTE prophylaxis rates in at‐risk hospitalized medical patients in the United States were 48% and 52%.[9, 16] Amin and colleagues found the overall rate of VTE prophylaxis among 227 US hospitals to be 62%.[17] Accordingly, our intervention, which resulted in an 82% compliance rate on a large medical service and was associated with a significantly reduced VTE incidence, appears to be highly effective. Our results are likely more favorable in that beyond length of stay criteria, we did not exclude less acutely ill medical patients from analyses.

Michota summarized quality improvement studies for VTE prevention.[10] Among 9 studies attempting to improve VTE prophylaxis, 2 used electronic decision support as a primary strategy, and only 1, by Kucher et al., used a computerized approach on a medical service.[18] This study showed significant improvement in VTE prophylaxis and incidence in patients randomized to a provider computer program. The intervention was complex, requiring specification of 8 patient‐level risk factors via a customized database, and the physician to recommend specific prophylactic regimens accordingly. Our findings, using a more basic approach, similarly support the effectiveness of using automated decision support, which can be readily modified as evidence‐based guidelines evolve.

Overall adoption of information technology systems in US hospitals is low: only 7.6% of hospitals have a basic system, and 17% have computerized physician order entry.[19] As hospitals have been financially incentivized to adopt such systems, our relatively simple intervention may prove to be readily generalizable across varied vendor systems.[20] The intervention involved order sets triggered by automated logic, corollary information, and a hard stop to prompt VTE prophylaxis. Within the context of intensified emphasis on reducing harm in the inpatient setting and various pay for performance programs, our intervention is also of importance to payers.[3, 5] Using national data in year 2000, Zhan and Miller calculated the excess charges per case associated with VTE to be $21,709.[21]

In conclusion, a relatively simple automated clinical decision support application significantly improved rates of VTE prophylaxis and was associated with significantly lower hospital‐acquired VTE incidence in hospitalized medicine patients, with a reasonable safety profile.

Over 900,000 incident and recurrent venous thromboembolism (VTE) events occur in the United States each year, resulting in nearly 300,000 fatalities.[1] VTE, including deep vein thrombosis (DVT) and pulmonary embolism (PE), is among the most common causes of death in the United States, with more people dying annually from VTE than motor vehicle accidents and breast cancer.[2]

Accordingly, healthcare policy makers and regulators have placed greater emphasis on VTE prevention, including use of VTE prophylaxis measures in the Centers for Medicare and Medicaid Services (CMS) value‐based purchasing (pay for performance) program and the Joint Commission's adoption of a national hospital patient safety goal related to anticoagulation therapy.[3, 4] Beginning in 2008, VTE events following hip and knee procedures were included as 1 of 10 hospital‐acquired conditions for which CMS would not pay for associated additional costs of care.[5]

A typical 300‐bed hospital can expect roughly 150 cases of hospital‐acquired VTE annually.[6] Up to 75% of these cases will occur on the medicine service, where nearly every patient has 1 or more VTE risk factor.[7] Although effective preventive modalities exist, prophylaxis rates among medical patients have been noted to be <50%.[8, 9] While quality improvement interventions have been shown to be effective in improving compliance with VTE prophylaxis, there are few studies describing effectiveness of these interventions in electronic health record (EHR) environments.[10] As EHR implementation accelerates, it will be essential to define the strengths and limitations of various decision support approaches to optimally improve patient safety.

We sought to evaluate the effectiveness and safety of a computerized decision support application, which was designed as part of a quality improvement initiative to improve rates of VTE prophylaxis rates on the medicine services at 2 hospital sites.

METHODS

RESULTS

Table 1 compares the effectiveness of the decision support module intervention in medicine intervention and in nonmedicine (nonintervention) services. Among medicine service patients, any VTE prophylaxis ordering increased from 61.9% to 82.1% (P < 0.001), and pharmacologic VTE prophylaxis increased from 59.0% to 74.5% (P < 0.001). Smaller but significant increases were observed on nonmedicine services. Hospital‐acquired VTE incidence on medicine services decreased significantly, from 0.65% to 0.42% (P = 0.008) and nonsignificantly on nonmedicine services.

Table 2 shows ordering patterns for major VTE prophylaxis modalities. Among eligible medicine service patients, rates of low molecular weight heparin prophylaxis increased from 13.0% to 23.7% (P < 0.001), and of unfractionated heparin prophylaxis from 35.1% to 40.7% (P < 0.001). On nonmedicine services, there was no significant change in low molecular weight heparin use, and unfractionated heparin use increased significantly from 37.2% to 40.9% (P < 0.001). Proportions of patients receiving mechanical prophylaxis or not receiving prophylaxis decreased significantly by 37.8% on medicine services and by 9.8% on nonmedicine services Table 3 shows the safety of the decision support module. Bleeding rates increased on medicine services from 2.9% to 4.0% (P < 0.001) and on nonmedicine services from 7.7% to 8.6% (P = 0.043). Nonsignificant changes in thrombocytopenia rates were observed on both services.

DISCUSSION

Following implementation of a computerized decision support application to improve VTE prophylaxis on 2 hospital medicine services, we observed a significant increase in the rate of overall and pharmacologic VTE prophylaxis use and a significant decrease in the incidence of hospital‐acquired VTE. Changes were of greater magnitude and significance on medicine services where the intervention was deployed.

Rates of any VTE prophylaxis and pharmacologic VTE prophylaxis ordering on medicine services increased significantly by 32.7% and 26.3%, respectively. These rates increased on nonmedicine comparison services by a more modest 4.4% for any VTE prophylaxis and 6.7% for pharmacologic VTE prophylaxis. Although the medicine service intervention was designed to be agnostic to the type of prophylactic heparin preparation, the intervention resulted in a significant 82.4% increase in low molecular weight heparin use and a significant 16.0% increase in unfractionated heparin use. With respect to outcomes, we observed a 34.5% decrease (P < 0.001) in hospital‐acquired VTE incidence on medicine services and a nonsignificant decrease on nonmedicine services.

In assessing intervention safety, increased usage of VTE prophylaxis was not accompanied by an increase in thrombocytopenia, but was associated with an increase in bleeding from 2.9% to 4.0% (P < 0.001) on medicine services and from 7.7% to 8.6% (P = 0.043) on non‐medicine services. As our intervention was a quality improvement project, we conducted a brief post hoc analysis to evaluate the increased bleeding rate on the medicine service following intervention. A random sample of 50 records of medicine patients who had received VTE prophylaxis and had a subsequent bleeding event was reviewed. Findings are summarized in Table 4. Prophylaxis was used appropriately in 100% of cases. Bleeding episodes were minor in that no case required more than 2 U of packed red blood cells. The most common clinical scenario was a patient with baseline anemia, typically with chronic kidney disease, who had a slight decrease in hematocrit of unclear etiology requiring 1 U of blood.

Although the intervention occurred on medicine services, favorable albeit smaller changes were observed on nonmedicine services. We expected this favorable secular trend because of VTE prophylaxis awareness efforts across the organization as a whole. There was also ongoing focus on VTE prevention and outcomes by policymakers, regulatory agencies, and professional societies during the time period of study.[3, 4, 5, 12] Public reporting of CMS inpatient surgical VTE prophylaxis measures was required throughout the study period.[13] Changes observed on medicine services occurred during a period where there were no publicly reported measures of VTE prophylaxis for inpatient medicine services.

Our study had several limitations. We derived our eligibility criteria for VTE prophylaxis based on administrative data. To address this, we incorporated accepted standardized definitions,[11] used clinical data elements in our queries beyond ICD‐9 codes (eg, platelet count), and applied pertinent exclusion criteria (eg, length of stay 1 day or less). VTE events that were present on admission were excluded from analyses. However, as these community‐acquired VTE events may be caused by inadequate VTE prophylaxis during a prior hospitalization, the overall true incidence of hospital‐acquired VTE was likely underestimated.

With respect to the hospital‐acquired VTE outcome, we did not distinguish superficial from deep VTE. A consistent AHRQ definition of 13 ICD‐9 VTE codes was used to identify clinically significant VTE events for the periods before and after the intervention. Although the present on admission code identified VTE events that were hospital acquired, 1 new acute VTE ICD‐9 code was added in October 2009, allowing for more specific coding of acute, isolated, upper extremity VTE. Accordingly, our postintervention hospital‐acquired VTE rate may have slightly underestimated the true hospital‐acquired VTE incidence by omitting some coded acute, isolated, upper extremity VTE cases (if not coded using the prior Other VTE codes). In a study in a teaching hospital setting, isolated upper extremity VTE accounted for up to 21% of all symptomatic VTE events among adults.[14]

With respect to VTE prophylaxis, the study evaluated use in a dichotomous fashion but did not assess appropriateness, or adequacy of dosing of pharmacologic agents. We did not employ the intervention in a randomized fashion on the medicine service. As our project was a quality improvement intervention, we used a concurrent control group of nonmedicine service patients to assess potential secular trend bias.

With respect to the safety of the intervention, the record review we performed supported the appropriateness of prophylaxis use following the intervention, but was not designed to establish whether the increase in prophylaxis use was the proximate cause of bleeding events observed. Similarly, as specific testing for heparin‐induced thrombocytopenia was not used, the lack of significant change in thrombocytopenia rates before and after the intervention cannot directly establish the intervention's safety. Finally, our study also included only in‐hospital end points.

The rate of VTE prophylaxis use in hospitals has been noted to be disappointing.[15] Two large multinational studies found that VTE prophylaxis rates in at‐risk hospitalized medical patients in the United States were 48% and 52%.[9, 16] Amin and colleagues found the overall rate of VTE prophylaxis among 227 US hospitals to be 62%.[17] Accordingly, our intervention, which resulted in an 82% compliance rate on a large medical service and was associated with a significantly reduced VTE incidence, appears to be highly effective. Our results are likely more favorable in that beyond length of stay criteria, we did not exclude less acutely ill medical patients from analyses.

Michota summarized quality improvement studies for VTE prevention.[10] Among 9 studies attempting to improve VTE prophylaxis, 2 used electronic decision support as a primary strategy, and only 1, by Kucher et al., used a computerized approach on a medical service.[18] This study showed significant improvement in VTE prophylaxis and incidence in patients randomized to a provider computer program. The intervention was complex, requiring specification of 8 patient‐level risk factors via a customized database, and the physician to recommend specific prophylactic regimens accordingly. Our findings, using a more basic approach, similarly support the effectiveness of using automated decision support, which can be readily modified as evidence‐based guidelines evolve.

Overall adoption of information technology systems in US hospitals is low: only 7.6% of hospitals have a basic system, and 17% have computerized physician order entry.[19] As hospitals have been financially incentivized to adopt such systems, our relatively simple intervention may prove to be readily generalizable across varied vendor systems.[20] The intervention involved order sets triggered by automated logic, corollary information, and a hard stop to prompt VTE prophylaxis. Within the context of intensified emphasis on reducing harm in the inpatient setting and various pay for performance programs, our intervention is also of importance to payers.[3, 5] Using national data in year 2000, Zhan and Miller calculated the excess charges per case associated with VTE to be $21,709.[21]

In conclusion, a relatively simple automated clinical decision support application significantly improved rates of VTE prophylaxis and was associated with significantly lower hospital‐acquired VTE incidence in hospitalized medicine patients, with a reasonable safety profile.