Trends In Thromboprophylaxis Use In US Hospitals, 2006–2010

The use of thromboprophylaxis among at-risk groups of inpatients to prevent hospital-associated venous thromboembolism (HA-VTE) has long been considered suboptimal. Little is known, though, whether utilization of anticoagulants in inpatient settings has increased in recent years. The objective of this study was to assess trends in the administration of anticoagulants to inpatients in a sample of US hospitals from 2006 through 2010 and to further evaluate how trends in utilization vary by type of patient group.

A comprehensive national database of all-payer billing records from more than 600 US acute care hospitals, the Truven Health MarketScan® Hospital Drugs Database, was accessed for the years 2006 through 2010. Uniquely, this national hospital database contains records on prescription medications administered in the inpatient setting. Data were analyzed for a subset of hospitals for which an indicator of potential record error was zero. Data for this analysis were contributed by 394 hospitals in 2006 and 333 hospitals in 2010. The analysis was restricted to inpatient admissions of longer than 1 day for adult (age ≥ 18 years) patients who were neither admitted from nor discharged to another acute care hospital (i.e., no hospital transfers). Records were excluded for admissions with a diagnosis that could require anticoagulation for treatment, i.e., deep vein thrombosis, pulmonary embolism, atrial fibrillation, stroke, or myocardial infarct. Total admissions included were 3,188,966 in 2006 and 2,554,806 in 2010.

For the purposes of this study, records with one or more prescriptions for the following anticoagulants--enoxaparin, dalteparin, fondaparinux, or warfarin--were classified as presumed thromboprophylaxis since conditions for which anticoagulants are prescribed as treatment had been excluded. In addition, administration of unfractionated heparin of 1,000 U or more was considered prophylactic; low-dose heparin prescriptions (< 1000 U) were assumed to be used as a heparin flush. Anticoagulation prophylaxis rates were assessed for all inpatients and for 5 selected at-risk patient groups based on ICD-9-CM codes used for the same patient groups in Amin A, et al. (2011; 2012): hip/knee surgery, cancer, congestive heart failure (CHF), severe lung disease (including chronic obstructive pulmonary disease), and infectious disease. The associated numbers of admissions in 2010 and the percentages of all admissions for the five at-risk groups are: 52,517 (2.1%) knee/hip, 127,407 (5.0%) cancer, 33,212 (1.3%) severe lung disease, 28,514 (1.1%) CHF, and 27,541 (1.1%) infection.

Provisional results indicate that the frequency of administration of thromboprophylaxis in a sample of US inpatient hospitalizations increased over time, from 34.0% in 2006 to 41.40% in 2010, a relative increase of 21.5% in a 4-year period. The use of anticoagulation was highest among major orthopedic surgical patients at each point, 85.97% in 2006 and 87.40% in 2010. The second highest use was observed in hospitalizations for patients with severe lung disease, increasing from 65.33% in 2006 to 69.63% in 2010. Use of anticoagulants for hospitalizations with CHF diagnoses increased from 60.61% in 2006 to 67.99% in 2010. Increases in use of anticoagulation were larger in both absolute and relative terms for two other groups of at-risk hospitalizations. For hospitalizations associated with infectious disease diagnoses, the frequency of use increased from 46.03% in 2006 to 57.71% in 2010, a relative increase of 25.4%. Finally, the largest relative increase in thromboprophylaxis use in at-risk patient groups was observed for hospitalizations associated with cancer diagnoses, among which use increased from 40.52% in 2006 to 52.53% in 2010, a relative increase of 29.6%.

These data suggest that substantial increases have occurred in recent years in the frequency with which anticoagulants are prescribed to US inpatients for the prevention of HA-VTE. Additional analyses are being conducted to assess whether increased use of anticoagulants for thromboprophylaxis has been associated with outcomes such as changes in the frequency of in-hospital bleeding events that require treatment.