DVT surveillance program in the ICU: analysis of cost-effectiveness

Abstract

Background: Venous Thrombo-embolism (VTE--Deep venous thrombosis (DVT) and/or pulmonary embolism (PE)--in traumatized patients causes significant morbidity and mortality. The current study evaluates the effectiveness of DVT surveillance in reducing PE, and performs a cost-effectiveness analysis.

Methods: All traumatized patients admitted to the adult ICU underwent twice weekly DVT surveillance by bilateral lower extremity venous Duplex examination (48-month surveillance period--SP). The rates of DVT and PE were recorded and compared to the rates observed in the 36-month pre-surveillance period (PSP). All patients in both periods received mechanical and pharmacologic prophylaxis unless contraindicated. Total costs--diagnostic, therapeutic and surveillance--for both periods were recorded and the incremental cost for each Quality Adjusted Life Year (QALY) gained was calculated.

Results: 4234 patients were eligible (PSP--1422 and SP--2812). Rate of DVT in SP (2.8%) was significantly higher than in PSP (1.3%) - p<0.05, and rate of PE in SP (0.7%) was significantly lower than that in PSP (1.5%) - p<0.05. Logistic regression demonstrated that surveillance was an independent predictor of increased DVT detection (OR: 2.53 - CI: 1.462-4.378) and decreased PE incidence (OR: 0.487 - CI: 0.262-0.904). The incremental cost was $509,091/life saved in the base case, translating to $29,102/QALY gained. A sensitivity analysis over four of the parameters used in the model indicated that the incremental cost ranged from $18,661 to $48,821/QALY gained.

Conclusions: Surveillance of traumatized ICU patients increases DVT detection and reduces PE incidence. Costs in terms of QALY gained compares favorably with other interventions accepted by society.

Figure 1. Figure showing the rates of deep vein thrombosis (DVT) and pulmonary embolism (PE) during the pre-surveillance period (PSP: 2001–03) and the surveillance period (SP: 2004–07).

#p<0.05 – DVT (PSP vs SP); *p<0.05 – PE (PSP vs SP).

Figure 2. Figure showing a sensitivity analysis on the incremental cost to obtain one additional QALY.

The bars represent upper and lower bounds on the incremental cost relative to the base case of $29,102 (dashed line) with respect to the bounds on each parameter value. In this figure, the discount rate ranges from 0% to 5%, the difference in the PE incidence rate between PSP and SP ranges from 0.2% to 1.4%, the PE fatality rate ranges from 5% to 10%, and the health state utility ranges from 0.8 to 1.0.

Figure 3. Incremental dollar cost per quality adjusted life year (QALY) saved for selected interventions as compared to the cost of deep venous thrombosis surveillance (DVT Sur.).

The bars represent range of cost from the best case scenario (most cost effective) to the worst case scenario (least cost effective) for each intervention. CPR: cardio-pulmonary resuscitation, APC: activated protein C for sepsis, tPA for AMI: tissue plasminogen activator for acute myocardial infarction, CABG: coronary artery bypass grafting, NICU: neonatal intensive care unit. The bracketed number represents the reference the data is derived from.