Performance of the Wells score in patients with suspected pulmonary embolism during hospitalization: a delayed-type cross sectional study in a community hospital.

Introduction: The role of the Wells score for patients who develop signs and symptoms of pulmonary embolism (PE) during hospitalization has not been sufficiently validated. The aim of this study is to evaluate the performance of the Wells score for inpatients with suspected PE and to evaluate the prevalence of pulmonary embolism.

Materials And Methods: We conducted a cross sectional study nested in the prospective Institutional Registry of Thromboembolic Disease at Hospital Italiano de Buenos Aires from June 2006 to March 2011. We included patients who developed symptoms of pulmonary embolism during hospitalization. Patients were stratified based on the Wells score as PE likely (>4 points) or PE unlikely (≤4 points). The presence of pulmonary embolism was defined by pre-specified criteria.

Results: Six hundred and thirteen patients met the inclusion criteria, with an overall prevalence of PE of 36%. Two hundred and nineteen (34%) were classified as PE likely and 394 (66%) as PE unlikely with a prevalence of PE of 66% and 20%, respectively. The Wells score showed a sensitivity of 65 (95% CI 59-72), specificity 81 (95% CI 77-85), positive predictive value 66 (95% CI 60-72) and negative predictive value 80 (95% CI 77-84).

Conclusions: The Wells Score is accurate to predict the probability of PE in hospitalized patients and this population had a higher prevalence of PE than other cohorts. However, the score is not sufficiently predictive to rule out a potentially fatal disorder.