A computer program was developed to identify consecutive hospitalized patients at increased risk for DVT. The program used eight common risk factors to determine each patient’s risk profile for DVT and each risk factor was assigned a score. A cumulative score of four or higher was used to determine patients at high risk for DVT. The computer alert program was screened daily to identify patients whose score increased to four or higher after admission into the hospital. If the cumulative risk score was at least four, the computer program reviewed the current electronic orders and active medications for the use of DVT prophylaxis.
In the study, 2,506 consecutive adult patients were identified as high risk for DVT. Further,1,255 were randomized to the intervention group—in which the responsible physician received one electronic alert about the risk of DVT—and 1,251 patients were randomized to the control group in which no alert was issued. The 120 physicians involved took care of patients in the intervention and control groups. Physicians responsible for the control group were not aware that patients were being followed for clinical events. When physicians received alerts, they had to acknowledge them and could either withhold prophylaxis or order it on the same computer screen.
Patients were followed for 90 days after the index hospitalization. The primary end point was clinically apparent DVT or pulmonary embolism (PE). Safety end points included mortality at 30 days, and the rate of hemorrhagic events at 90 days.
The results showed that prophylactic measures were ordered for 421 of the 1,255 patients in the intervention group (33.5%) and 182 of the 1,251 patients in the control group (14.5%, p <0.001). There were higher rates of both mechanical (10% versus 1.5%, p<0.001) and pharmacological (23.6% versus 13.0%, p<0.001) prophylaxis in the intervention group. The primary end point of DVT or PE at 90 days occurred in 61 patients in the intervention group (4.9%) as compared with 103 patients in the control group (8.2%).
The computer alert reduced the risk of events at 90 days by 41% (HR 0.59; 95% CI 0.43 to 0.81; P=0.001). Of the patients who received prophylaxis 5.1% had DVT or PE compared with 7.0% of those who did not. In the intervention group, DVT or PE occurred in 20 of 421 (4.8%) patients who received prophylaxis compared with 41 of 834 (4.9%) who did not receive any. In the control group, the same numbers were 11 of 182 (6.0%) and 91 of 1,069 (8.5%).
Some of this benefit might be attributed to the additional preventive measures such as physiotherapy and early ambulation in patients assigned to the intervention group. Diagnostic bias also could have played into the results. Not all patients were screened for VTE, and it is likely that symptomatic patients without prophylaxis were screened more frequently than symptomatic patients with prophylaxis. Because physicians took care of both the control and intervention group, alerts received by physicians in the control group could have influenced their decision in the control group as well.
The authors concluded that instituting computer alerts markedly reduced the rates of DVT or PE in hospitalized patients.