Evaluation of venous thromboembolism risk following hospitalization

Abstract

A better understanding of the relationship between outpatient venous thromboembolism (VTE) and prior hospitalization is needed including data regarding the utilization of inpatient pharmacologic VTE prophylaxis and its effect on outpatient venous thromboembolic risk. The primary objective was to assess the association between development of outpatient VTE and inpatient hospitalization within the previous 90 days. Additional outcome measures included describing patients who received pharmacologic anticoagulation during hospitalization and identification of factors independently associated with VTE. Case patients in this matched case-control study were diagnosed with an outpatient deep vein thrombosis or pulmonary embolus between January 2005 and December 2007 and were matched on age with up to five to patients who were seen for an outpatient health maintenance visit but had no VTE during the same time frame as their matched case. Information collected from electronic administrative databases and patient medical records included health services utilization, medication use, medical diagnoses, and patient demographic information. Of 2190 cases, 560 patients (25.6%) compared to 151 (1.4%) of 10,942 control patients were hospitalized in the previous 90 days (P < 0.001). Among hospitalized patients, 53.5% of cases and 47.0% of controls received an anticoagulant during hospitalization (P = 0.186). Factors associated with a VTE diagnosis included hospitalization for a surgical, medical, or orthopedic indication in the previous 90 days, younger age, longer hospitalization, cancer and an elevated Chronic Disease Score. A strong association exists between outpatient VTE diagnosis and hospitalization and gaps in pharmacologic prophylaxis utilization during hospitalization are evident.