Association Between Inpatient Surveillance and Venous Thromboembolism Rates After Hospital Discharge

Venous thromboembolism (VTE) surveillance practices in hospitals, but not adherence to Surgical Care Improvement Program VTE prophylaxis measures, have been reported to explain the variation in VTE rates in hospitals.

To examine the relationship between inpatient surveillance testing for VTE and postdischarge VTE rates at the hospital level to determine whether more frequent inpatient surveillance is associated with reduced occurrence of postdischarge VTEs.

Retrospective study of a US national cohort of Veterans Affairs (VA) patients. National VA Surgical Quality Improvement Program outcome data were linked to VA administrative data on patients undergoing inpatient surgery from 2005 to 2009 and were included in the Surgical Care Improvement Program VTE measurement population.

Surveillance was identified using Current Procedural Terminology codes for diagnostic VTE imaging. Relationships between hospital-level surveillance and VTE rates were assessed with Pearson correlation coefficients, and the postdischarge VTE rate was modeled using linear regression, adjusting for hospital volume, inpatient VTE rate, inpatient surveillance rate, and case mix.

Of 25 975 patients at 79 VA facilities, 296 (1.4%) experienced a VTE during the index hospitalization, and 114 (0.4%) experienced a postdischarge VTE within 30 days after surgery. The median length of stay was 11 days for those with a positive surveillance test result and 9 days for those with a negative test result. There was a positive correlation between inpatient surveillance and inpatient VTE rates (R = 0.33, P = .003) but no significant correlation of inpatient surveillance with either postdischarge surveillance (R = 0.11, P = .29) or postdischarge VTE rates (R = 0.03, P = .76). In an adjusted regression model of the postdischarge VTE rate, only the inpatient VTE rate was significant (β = 0.13, P = .05).

Hospitals with higher VTE surveillance rates have higher inpatient VTE rates but not decreased postdischarge VTE rates. However, hospitals with higher inpatient VTE rates have higher postdischarge VTE rates, which suggests that surveillance may be influenced by higher observed rates and not surveillance practices alone.