National and regional trends in deep vein thrombosis hospitalization rates, discharge disposition, and outcomes for Medicare Beneficiaries, 1999-2010

Background: Older adults are at increased risk of developing deep vein thrombosis (DVT) and its complications such as pulmonary embolism and post-thrombotic syndrome. The APHA has cited DVT as one of the most preventable causes of death. Little is known about recent national trends of DVT in the context of secondary prevention efforts and home treatment options during the past decade.

Methods:  Inpatient Medicare standard analytic files were used to identify 100% of Fee-For-Service (FFS) patients aged ≥65 years who had a principal discharge diagnosis for DVT from 1999 to 2010. We linked inpatient data with the Medicare denominator file to report DVT rates per 100,000 person-years. Mortality (in-hospital, 30-day, 6-month, and 1-year), readmission, length of stay, and discharge disposition were ascertained through corresponding vital status files. We used mixed-effects models to calculate adjusted outcomes.

Results: Overall, there were 726,423 patients with DVT in Medicare FFS from 1999 to 2010. The DVT hospitalization rate adjusted for age, sex, and race declined from 264 per 100,000 person-years in 1999 to 167 per 100,000 person-years in 2010, a relative decline of 36.7% (P<0.0001). Hospitalizations declined for all subgroups by age, gender, and race with the exception of Blacks (316 to 382 per 100,000 person years, a relative increase of 20.8%). Hospitalizations declined for all states but Florida and Hawaii. The length of hospital stay decreased from 6.1 days in 1999 to 5.0 days in 2010, and the proportion of patients discharged to home decreased from 57.2% to 44.1%, with more patients discharged with home care (from 14.0% to 23.9%) and skilled nursing facilities (from 22.7% to 24.4%) during the study period. In-hospital and risk-adjusted 30-day, 6-month, and 1-year mortality remained relatively stable across the study period. However, risk-adjusted 30-day readmission rates increased from 13.4% in 1999 to 15.1% in 2010.

Conclusions: The overall DVT hospitalization rate declined from 1999 to 2010, except for Black patients and those in Florida and Hawaii.  Declines in hospitalizations and increases in readmissions may reflect changes in clinical practice pattern that favor outpatient rather than inpatient management, or earlier transition to outpatient care for management of DVT.