The original and simplified Wells rules and age-adjusted D-dimer testing to rule out pulmonary embolism: an individual patient data meta-analysis

Essentials Evidence for the simplified Wells rule in ruling out acute pulmonary embolism (PE) is scarce. This was a post-hoc analysis on data from 6 studies comprising 7268 patients with suspected PE. The simplified Wells rule combined with age-adjusted D-dimer testing may safely rule out PE. Given its ease of use, the simplified Wells rule is to be preferred over the original Wells rule. Background The Wells score and D-dimer testing can safely rule out pulmonary embolism (PE). A simplification of the Wells score has been proposed to improve clinical applicability, but evidence on its performance is scarce. Objectives To compare the performances of the original and simplified Wells scores alone and in combination with age-adjusted D-dimer testing. Methods Individual patient data from 7268 patients with suspected PE enrolled in six management studies were used to evaluate the discriminatory performances of the original and simplified Wells scores. The efficiency and failure rate of the dichotomized original and simplified scores combined with age-adjusted D-dimer testing were compared by use of a one-stage random effects meta-analysis. Efficiency was defined as the proportion of patients in whom PE could be considered to be excluded on the basis of a 'PE unlikely' Wells score and a negative age-adjusted D-dimer test result. Failure rate was defined as the proportion of patients with symptomatic venous thromboembolism during a 3-month follow-up. Results The discriminatory performances of the original and simplified Wells scores were comparable (c-statistic 0.73 [95% confidence interval (CI) 0.72-0.75] versus 0.72 [95% CI 0.70-0.73]). When combined with age-adjusted D-dimer testing, the original and simplified Wells rules had comparable efficiency (3% [95% CI 25-42%] versus 30% [95% CI 21-40%]) and failure rates (0.9% [95% CI 0.6-1.5%] versus 0.8% [95% CI 0.5-1.3%]). Conclusion The original and simplified Wells rules combined with age-adjusted D-dimer testing have similar performances in ruling out PE. Given its ease of use in clinical practice, the simplified Wells rule is to be preferred