Low agreement for assessing the risk of postoperative deep venous thrombosis when deciding prophylaxis strategies: a study using clinical vignettes

Martin O'Flaherty¹ , Kaja Lerum² , Paula Martin² and Daniel Grassi¹

¹Departamento de Medicina, Hospital Universitario Austral

²Clinical Internship, Facultad de Ciencias Biomédicas, Universidad Austral, Buenos Aires, Argentina

author email corresponding author email

BMC Health Services Research 2002, 2:16doi:10.1186/1472-6963-2-16


Published:	16 August 2002

Abstract

Background

Several clinical practice guidelines (CPG) on antithrombotic prophylaxis in surgical patients help to decide about the prophylaxis strategy based on the patient risk of deep venous thrombosis (DVT). However, the physician risk estimates of DVT could have little inter-observer reproducibility, which could lead to different individual prophylaxis practices.

Methods

Physicians were asked to evaluate DVT risk in eight clinical vignettes, describing actual patients cared for in our hospital. The vignettes included all possible levels of DVT risk.

Results

The degree of prophylaxis strategies accuracy was 63% (95% CI 523–75%). Overall agreement was 0.32 (z = 7.61, p < 0.001) and for each level of risk kappa was 0.38 (z = 6.50, p < 0.001); 0.1 (z = 1.65, p < 0.049) and 0.5 (z = 8.45, p < 0.001) for small, moderate and high risk group respectively

Conclusions

Our results showed that there is poor agreement when physicians have to evaluate the risk for postoperative DVT, and in the cases of low and moderate risks of DVT there is the smallest agreement. In addition, the data also showed that the overall accuracy of DVT prophylaxis strategy was only moderate and the risk evaluation did not correlate to the selection of the strategy. The issue of inter-observers variability should be taken into account when CPG performance are analysed, especially when considering the risk-evaluation to choose the appropriate actions.