Considerable emphasis has been placed on improving the identification of hospitalized patients at high risk for venous thromboembolism (VTE) so that they receive adequate prophylaxis. However increased availability of outpatient procedures, increased utilization of in-dwelling catheters, and shortened length of hospital stay might be expected to lead to an increasing outpatient population that is also high risk for VTE. The purpose of this study was to compare risk factor profile, previous VTE prophylaxis use, and outcomes of patients who developed VTE in the outpatient setting versus those who developed VTE after admission for another non-VTE related diagnosis.
The medical records of all residents from the Worcester,MA area (2000 census=478,000) diagnosed with ICD-9 codes consistent with possible VTE at all 11 Worcester hospitals in 1999 are being reviewed by trained data abstractors. Validation of each case of VTE is performed using prespecified criteria. Information was collected about demographic and clinical characteristics, prior VTE prophylaxis, and hospital outcomes.
A total of 587 cases have been validated as acute VTE events for the year 1999. We present an interim analysis based on data from the first 392 cases enrolled. See Table 1 for characteristics of these patients stratified by setting of VTE development.
Patients who develop VTE in the outpatient setting were younger, more often female, and more likely to be on hormonal therapy than those who developed VTE during a hospitalization. They were just as likely to have a history of prior VTE, recent hospitalization or surgery, recent fracture, or recent cancer/chemotherapy. Utilization of prophylaxis (particularly anticoagulant) was suboptimal in patients who developed VTE during a hospitalization. It also was suboptimal after recent surgery or during prior hospitalizations in patients who developed VTE in the outpatient setting.
These data suggest that patients who develop VTE as outpatients have a high prevalence of risk factors, including recent surgery and/or hospitalization. Further research on the optimal identification of these high-risk patients and targetted outpatient VTE prophylaxis is warranted.
Frederick Spencer, None.