Prognostic clinical prediction rules to identify a low-risk pulmonary embolism: a systematic review and meta-analysis

. Background: Prognostic assessment is important for the management of patients with a pulmonary embolism (PE). A number of clinical prediction rules (CPRs) have been proposed for stratifying PE mortality risk. The aim of this systematic review was to assess the performance of prognostic CPRs in identifying a low-risk PE. Methods: MEDLINE and EMBASE databases were systematically searched until August 2011. Derivation and validation studies that assessed the performance of prognostic CPRs in predicting adverse events-risk in PE patients were included. Weighted mean proportion and 95% confidence intervals (CIs) of adverse events were then calculated and pooled using a fixed and a random-effects model. Statistical heterogeneity was evaluated through the use of I2 statistics. Results: Of 1125 references in the original search, 33 relevant articles were included. Nine CPRs were assessed in 37 cohorts, for a total of 35 518 patients. Pulmonary Embolism Severity Index and prognostic Geneva CPR were investigated in 22 and 6 cohorts, respectively. Eleven (29.7%) cohorts were of high quality. The median follow-up was 30 days. In low-risk PE patients, pooled short-term mortality (within 14 days or less) was 0.7% (95% CI 0.31.1%, random-effects model; I2 = 49.6%), 30-day mortality was 1.7% (95% CI 1.12.3%, random-effects model; I2 = 82.4%) and 90-day mortality was 2.2% (95% CI 1.23.4%, random-effects model; I2 = 59.8%). Conclusions: Prognostic CPRs efficiently identify PE patients at a low risk of mortality. Before implementing prognostic CPRs in the routine care of PE patients, well-designed management studies are warranted.