Cost-effectiveness of screening for deep vein thrombosis by ultrasound at admission to stroke rehabilitation.

OBJECTIVE

This project was a cost-effectiveness analysis of the practice of routine Doppler ultrasound screening for deep vein thrombosis (DVT) in patients with ischemic stroke at the time of admission to rehabilitation.

DESIGN

A decision-analysis model was created to compare 2 approaches for detecting DVT in a stroke population: (1) screening all patients with acute ischemic stroke at admission to stroke rehabilitation for DVT by Doppler ultrasound with subsequent treatment; or (2) clinical surveillance for signs of DVT and treatment after confirmation by Doppler ultrasound. The prevalence of DVT, risk of complication from DVT, and risk of complication from treatment were obtained from published reports. Costs are in 2004 dollars and the effectiveness was measured in quality-adjusted life-years (QALYs) gained. We conducted these analyses from a societal perspective.

SETTING

Inpatient stroke rehabilitation unit.

PARTICIPANTS

Not applicable.

INTERVENTION

Screening all patients with acute ischemic stroke at admission to stroke rehabilitation for DVT by Doppler ultrasound with subsequent treatment.

MAIN OUTCOME MEASURE

Cost in 2004 dollars per QALY gained by screening all patients with acute ischemic stroke at admission to stroke rehabilitation for DVT by Doppler ultrasound with subsequent treatment.

RESULTS

The expected utility of screening patients with ischemic stroke for DVT by Doppler ultrasound on admission to rehabilitation is 1.875 QALYs and that of not screening is 1.872 QALYs. The expected gain is .0026 QALYs (23 h). Obtaining this increase in quality-adjusted life incurs additional cost of 168 dollars per stroke patient and a marginal cost-effectiveness of 67,200 dollars for each QALY gained.

CONCLUSIONS

This study estimates that the cost-effectiveness ratio is considerably higher than that reported in other rehabilitation conditions and higher than the commonly stated level for an intervention to be considered cost-effective. The difference from previous reports primarily relates to the shorter life expectancy following stroke, the prevalence of occult DVT at admission, rate of complications of anticoagulation, and the estimates of the screening's test characteristics used in our study. Further study of these areas is likely to contribute to improving our understanding of the most appropriate care of these patients.