High Thromboembolism Rate Seen Among Inpatients

PHILADELPHIA — The “real-world” incidence of venous thromboembolism in a mixed group of U.S. patients who were hospitalized for medical illness was 5.6% during a median follow-up of about 15 months following their index hospitalization, in a review of more than 150,000 discharged patients aged 40 years or older.

This rate is two- to threefold higher than previously reported incidence rates for venous thromboembolism (VTE) in ill patients, Dr. Alex C. Spyropoulos and his associates reported in a poster at the annual meeting of the American College of Chest Physicians.

The high rate seen in this study may have been because the patients were followed for a relatively long period, the study included unselected patients and in some cases patients with comorbidities, and prophylaxis for VTE was underused, said Dr. Spyropoulos, medical director of the Clinical Thrombosis Center at the Lovelace Medical Center in Albuquerque, and his associates.

They used claim records from the PharMetrics database for 158,325 patients aged 40 years or older who were hospitalized and then discharged during 2001–2005. This database includes claims from more than 90 U.S. health insurance plans that together include more than 50 million beneficiaries.

Included in the review were patients hospitalized for a severe infectious disease (48%), cancer (25%), lung disease (17%), or heart failure (10%). Their average age was about 58 years, more than half the patients were women, and less than 1% of the patients had VTE during their index hospitalization. VTE prophylaxis with an anticoagulant was used by about 5% of the patients during the first 30 days following their hospital discharge. “The use of VTE prophylaxis in accordance with guideline recommendations remains low in medical patients,” the researchers noted.

During follow-up, deep vein thrombosis occurred in almost 4% of all patients, pulmonary embolism occurred in almost 1.5%, and both forms of VTE occurred in 0.2%. The total rate of all symptomatic VTE episodes was about 5.6%. The median time to VTE was 74 days.

The VTE rate was highest among the cancer patients, at almost 7.6%. The rate was lowest among patients with severe infectious disease, about 4.9%.

The strongest predictor of VTE during follow-up was VTE during the index hospitalization, which boosted the risk about ninefold, compared with patients without VTE during hospitalization. Other factors that increased VTE risk were having cancer, which raised the risk by about 34%, compared with the other morbidities studied, a longer index hospitalization, and a higher Charlson comorbidity score prior to the index hospitalization

The study was funded by Sanofi-Aventis. Dr. Spyropoulos had received research grants from and is a consultant to Sanofi-Aventis and other drug companies.