Incidence of hospital-acquired venous thromboembolic codes in medical patients hospitalized in academic medical centers

Abstract

Background: Hospital-acquired venous thromboembolism (HA-VTE, VTE occurring during a hospitalization) codes in hospital billing data are often used as a surrogate for hospital-associated VTE events occurring during or up to 30 days after a hospitalization, which are more difficult to measure.

Objective: Establish the incidence and composition of HA-VTE/superficial venous thrombosis (SVT) coded in a large cohort of medical patients.

Design: Retrospective analysis of discharges.

Setting: Eighty-three academic medical centers in UHC (formerly University HealthSystem Consortium).

Patients: Patients with medical diagnoses hospitalized >2 days between October 1, 2009, and March 31, 2011.

Measurements: Incidence and anatomic location of HA-VTE codes, defined as International Classification of Diseases, Ninth Revision, Clinical Modification codes for VTE coupled to a present-on-admission indicator flag set to "No."

Results: Among 2,525,068 medical hospitalizations, 12,847 (0.51%) cases had ≥1 thrombotic code; 2449 (19.1%) with pulmonary embolism (PE), and 3848 (30%) with lower-extremity deep venous thrombosis (LE-DVT) without PE. Upper-extremity DVT (2893; 22.5%) and SVT (3248; 25.3%) comprised the bulk of remaining cases. Among cases with HA-PE/LE-DVT, 34.3% had cancer, 47.8% received care in an intensive care unit, 78% had severe or extreme severity of illness, and 16.5% died in the hospital. Overall, 54.9% of the patients who developed a HA-PE/LE-DVT had been started on VTE pharmacoprophylaxis on hospital day 1 or 2.

Conclusion: At academic centers, HA-VTE/SVT is coded in 0.51% of medical inpatients, and HA-PE/LE-DVT is coded in half of those. Most patients with HA-PE/LE-DVT are severely ill and develop VTE despite receiving prophylaxis.