Low agreement for assessing the risk of postoperative deep venous thrombosis when deciding prophylaxis strategies: a study using clinical vignettes.
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.
O'Flaherty
Martin
M
Departamento de Medicina, Hospital Universitario Austral. moflaherty@cas.austral.edu.ar
Lerum
Kaja
K
Martin
Paula
P
Grassi
Daniel
D
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001118:Argentina / Q000453:epidemiology; D001458:Bandages / Q000706:statistics & numerical data; D003657:Decision Making; D004434:Early Ambulation / Q000706:statistics & numerical data; D005260:Female; D006493:Heparin / Q000627:therapeutic use; D006785:Hospitals, University / Q000592:standards; D006801:Humans; D008297:Male; D008485:Medical Audit; D008875:Middle Aged; D017762:Nadroparin / Q000627:therapeutic use; D015588:Observer Variation; D011183:Postoperative Complications / Q000145:classification / Q000453:epidemiology* / Q000517:prevention & control*; D017410:Practice Guidelines as Topic; D011292:Premedication / Q000706:statistics & numerical data; D018570:Risk Assessment / Q000706:statistics & numerical data*; D020246:Venous Thrombosis / Q000453:epidemiology* / Q000209:etiology / Q000517:prevention & control*
D017762:Nadroparin; D006493:Heparin