Targeted prophylactic anticoagulation based on the TRiP(cast) score in patients with lower limb immobilisation: a multicentre, stepped wedge, randomised implementation trial.

BACKGROUND: Prophylactic anticoagulation in emergency department patients with lower limb trauma requiring immobilisation is controversial. The Thrombosis Risk Prediction for Patients with Cast Immobilisation-TRiP(cast)-score could identify a large subgroup of patients at low risk of venous thromboembolism for whom prophylactic anticoagulation can be safely withheld. We aimed to prospectively assess the safety of withholding anticoagulation for patients with lower limb trauma at low risk of venous thromboembolism, defined by a TRiP(cast) score of less than 7. METHODS: CASTING was a stepped-wedge, multicentre, cluster-randomised trial with blinded outcome assessment. 15 emergency departments in France and Belgium were selected and randomly assigned staggered start dates for switching from the control phase (ie, anticoagulation prescription according to the physician's usual practice) to the intervention phase (ie, targeted anticoagulation according to TRiP(cast) score: no prescription if score <7 and anticoagulation if score was ≥7). Patients were included if they presented to a participating emergency department with lower limb trauma requiring immobilisation for at least 7 days and were aged 18 years or older. The primary outcome was the 3-month cumulative rate of symptomatic venous thromboembolism during the intervention phase in patients with a TRiP(cast) score of less than 7. The targeted strategy was considered safe if this rate was less than 1% with an upper 95% CI of less than 2%. The primary analysis was performed in the intention-to-treat population. This study is registered at ClinicalTrials.gov (NCT04064489). FINDINGS: Between June 16, 2020, and Sept 15, 2021, 15 clusters and 2120 patients were included. Of the 1505 patients analysed in the intervention phase, 1159 (77·0%) had a TRiP(cast) score of less than 7 and did not receive anticoagulant treatment. The symptomatic venous thromboembolism rate was 0·7% (95% CI 0·3-1·4, n=8/1159). There was no difference between the control and the intervention phases in the cumulative rate of symptomatic venous thromboembolism or in bleeding rates. INTERPRETATION: Patients with a TRiP(cast) score of less than 7 who are not receiving anticoagulation have a very low risk of venous thromboembolism. A large proportion of patients with lower limb trauma and immobilisation could safely avoid thromboprophylaxis. FUNDING: French Ministry of Health.

Derivation and validation of a risk-stratification model for patients with probable or proven COVID-19 in EDs: the revised HOME-CoV score.

BACKGROUND: The HOME-CoV (Hospitalisation or Outpatient ManagEment of patients with SARS-CoV-2 infection) score is a validated list of uniquely clinical criteria indicating which patients with probable or proven COVID-19 can be treated at home. The aim of this study was to optimise the score to improve its ability to discriminate between patients who do and do not need admission. METHODS: A revised HOME-CoV score was derived using data from a previous prospective multicentre study which evaluated the original Home-CoV score. Patients with proven or probable COVID-19 attending 34 EDs in France, Monaco and Belgium between April and May 2020 were included. The population was split into a derivation and validation sample corresponding to the observational and interventional phases of the original study. The main outcome was non-invasive or invasive ventilation or all-cause death within 7 days following inclusion. Two threshold values were defined using a sensitivity of >0.9 and a specificity of >0.9 to identify low-risk and high-risk patients, respectively. The revised HOME-CoV score was then validated by retrospectively applying it to patients in the same EDs with proven or probable COVID-19 during the interventional phase. The revised HOME-CoV score was also tested against original HOME-CoV, qCSI, qSOFA, CRB65 and SMART-COP in this validation cohort. RESULTS: There were 1696 patients in the derivation cohort, of whom 65 (3.8%) required non-invasive ventilation or mechanical ventilation or died within 7 days and 1304 patients in the validation cohort, of whom 22 (1.7%) had a progression of illness. The revised score included seven clinical criteria. The area under the curve (AUC) was 87.6 (95% CI 84.7 to 90.6). The cut-offs to define low-risk and high-risk patients were <2 and >3, respectively. In the validation cohort, the AUC was 85.8 (95% CI 80.6 to 91.0). A score of <2 qualified 73% of patients as low risk with a sensitivity of 0.77 (0.55-0.92) and a negative predictive value of 0.99 (0.99-1.00). CONCLUSION: The revised HOME-CoV score, which does not require laboratory testing, may allow accurate risk stratification and safely qualify a significant proportion of patients with probable or proven COVID-19 for home treatment.

Pulmonary embolism rule-out criteria (PERC) rule in European patients with low implicit clinical probability (PERCEPIC): a multicentre, prospective, observational study.

BACKGROUND: The ability of the pulmonary embolism rule-out criteria (PERC) to exclude pulmonary embolism without further testing remains debated outside the USA, especially in the population with suspected pulmonary embolism who have a high prevalence of the condition. Our main objective was to prospectively assess the predictive value of negative PERC to rule out pulmonary embolism among European patients with low implicit clinical probability. METHODS: We did a multicentre, prospective, observational study in 12 emergency departments in France and Belgium. We included consecutive patients aged 18 years or older with suspected pulmonary embolism. Patients were excluded if they had already been hospitalised for more than 2 days, had curative anticoagulant therapy in progress for more than 48 h, or had a diagnosis of thromboembolic disease documented before admission to emergency department. Physicians completed a standardised case report form comprising implicit clinical probability assessment (low, moderate, or high) and a list of risk factors including criteria of the PERC rule. They were asked to follow international recommendations for diagnostic strategy, masked to PERC assessment. The primary endpoint was the proportion of patients with low implicit clinical probability and negative PERC who had venous thromboembolic events, diagnosed during initial diagnostic work-up or during 3-month follow-up, as externally adjudicated by an independent committee masked to the PERC and clinical probability assessment. The upper limit of the 95% CI around the 3-month thromboembolic risk was set at 3%. We did all analyses by intention to treat, including all patients with complete follow-up. This trial is registered with ClinicalTrials.gov, number NCT02360540. FINDINGS: Between May 1, 2015, and April 30, 2016, 1773 consecutive patients with suspected pulmonary embolism were prospectively assessed for inclusion, of whom 1757 were included. 1052 (60%) patients were classed as having low clinical probability, 49 (4·7%, 95% CI 3·5-6·1) of whom had a venous thromboembolic event. In patients with a low implicit clinical probability, 337 (32%) patients had negative PERC, of whom four (1·2%; 95% CI 0·4-2·9) went on to have a pulmonary embolism. INTERPRETATION: In European patients with low implicit clinical probability, PERC can exclude pulmonary embolism with a low percentage of false-negative results. The results of our prospective, observational study allow and justify an implementation study of the PERC rule in Europe. FUNDING: French Ministry of Health.