Predicting acute and long-term mortality in a cohort of pulmonary embolism patients using machine learning.

BACKGROUND: Pulmonary embolism (PE) is a severe condition that causes significant mortality and morbidity. Due to its acute nature, scores have been developed to stratify patients at high risk of 30-day mortality. Here we develop a machine-learning based score to predict 30-day, 90-day, and 365-day mortality in PE patients. METHODS: The Birmingham and Black Country Venous Thromboembolism registry (BBC-VTE) of 2183 venous thromboembolism patients is used. Random forests were trained on a 70% training cohort and tested against 30% held-out set. The outcomes of interest were 30-day, 90-day, and 365-day mortality. These were compared to the pulmonary embolism severity index (PESI) and simplified pulmonary embolism severity index (sPESI). Shapley values were used to determine important predictors. Oral anticoagulation at discharge was also investigated as a predictor of mortality. RESULTS: The machine learning risk score predicted 30-day mortality with AUC 0.71 [95% CI: 0.63 - 0.78] compared to the sPESI AUC of 0.65 [95% CI: 0.57 - 0.73] and PESI AUC of 0.64 [95% CI: 0.56 - 0.72]. 90-day mortality and 365-day mortality were predicted with an AUC of 0.74 and 0.73 respectively. High counts of neutrophils, white blood cell counts, and c-reactive protein and low counts of haemoglobin were important for 30-day mortality prediction but progressively lost importance with time. Older age was an important predictor of high risk throughout. CONCLUSION: Machine learning algorithms have improved on standard clinical risk stratification for PE patients. External cohort validation is required before incorporation into clinical workflows.

The Birmingham and Black Country cohort of Venous Thromboembolism (BBC-VTE) registry: Rationale, design and preliminary results.

The Birmingham Black Country Venous Thromboembolism registry (BBC-VTE) is a multi-ethnic cohort of patients who suffered a first episode of venous thromboembolism (VTE) and were admitted to various hospital sites across the West Midlands and Black Country regions in the United Kingdom. The BBC-VTE registry is a retrospective, observational cohort study which aims to collect data on outcomes including mortality, bleeding and VTE recurrence in this patient cohort. In addition, the comprehensive, structured data collected will allow us to conduct machine learning analyses for risk prediction in such patients and also to compare to previously derived mortality scores such as the PESI and the simplified PESI (sPESI). Our registry included 2183 patients admitted to hospital between the years 2012-14 and 2016-18 with a first episode of VTE and the mean follow up was 36 months. The cohort was ethnically diverse with 72.5% white Caucasian, 8.2% Asian (including South Asian), 6.7% black, and 11.7% of unknown/other ethnicity. Of those admitted during the collection period 56% had PE, 40% had DVT, with the rest presenting with both PE and DVT. Around 7% of patients went on to develop a bleeding episode and 36% died (all-cause mortality). Of the deaths, 10% of patients died within 30-days of admission (30-day mortality), with 16% dying within 90 days. In summary, this study investigates real-world outcomes of patients after the first index VTE event and attempts to bridge the gap in evidence for contemporary data in this population which will allow to construct more accurate risk prediction tools and management decisions.

Post pulmonary embolism syndrome: a common, underdiagnosed complication that is not well recognised.

A 56-year-old man developed chronic breathlessness which persisted for years after he suffered acute pulmonary embolism (PE) despite all investigations being subsequently normal. This case illustrates a very common complication which occurs in up to half of all patients after an acute PE which has been labelled 'post pulmonary embolism syndrome', yet it is not well recognised and at present there is not much research into the prevention or even possible treatment options for patients who develop these symptoms.

Uncommon condition mimicking non-resolving pneumonia and malignancy on radiography that improves dramatically with a course of steroids.

A 58-year-old man was seen in a specialist respiratory clinic, with non-resolving pneumonia. Various investigations including CT scan, bronchoscopy and CT-guided biopsy were carried out for suspected malignancy but they could not find any evidence of neoplasia or anything else of significance. The lung mass that persisted for years later resolved with a course of steroids, at which point further investigations for alternative differential diagnoses suggested a surprising conclusion.

The effect of medical school on postgraduate fitness to practise decisions: a retrospective cohort study.

Given evidence of differences between UK medical schools' curricula and assessments, and their graduates' performance in Royal college examinations, this retrospective cohort study analyses the effect of medical school on the incidence of General Medical Council fitness to practise sanctions.