Objective: Prospectively validate two prognostic scores, pre-hospitalisation (SOARS) and hospitalised mortality prediction (4C Mortality Score), derived from the coronavirus disease 2019 (COVID-19) first wave, in the evolving second wave with prevalent B.1.1.7 and parent D614 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, in two large United Kingdom (UK) cohorts.
Design: Prospective observational cohort study of SOARS and 4C Mortality Score in PREDICT (single site) and multi-site ISARIC (International Severe Acute Respiratory and Emerging Infections Consortium) cohorts.
Setting: Protocol-based data collection in UK COVID-19 second wave, between October 2020 and January 2021, from PREDICT and ISARIC cohorts.
Participants: 1383 from single site PREDICT cohort and 20,595 from multi-site ISARIC cohort.
Main outcome measures: Relevance of SOARS and 4C Mortality Score derived from the COVID-19 first wave, determining in-hospital mortality and safe discharge in the UK COVID-19 second wave.
Results: Data from 1383 patients (median age 67y, IQR 52-82; mortality 24.7%) in the PREDICT and 20,595 patients from the ISARIC (mortality 19.4%) cohorts showed both SOARS and 4C Mortality Score remained relevant despite the B.1.1.7 variant and treatment advances. SOARS had AUC of 0.8 and 0.74, while 4C Mortality Score had an AUC of 0.83 and 0.91 for hospital mortality, in the PREDICT and ISARIC cohorts respectively, therefore effective in evaluating both safe discharge and in-hospital mortality. 19.3% (231/1195, PREDICT cohort) and 16.7% (2550/14992, ISARIC cohort) with a SOARS of 0-1 were potential candidates for home discharge to a virtual hospital (VH) model. SOARS score implementation resulted in low re-admission rates, 11.8% (27/229), and low mortality, 0.9% (2/229), in the VH pathway. Use is still suboptimal to prevent admission, as 8.1% in the PREDICT cohort and 9.5% in the ISARIC cohort were admitted despite SOARS score of 0-1.
Conclusion: SOARS and 4C Mortality Score remains valid, providing accurate prognostication despite evolving viral subtype and treatment advances, which have altered mortality. Both scores are easily implemented within urgent care pathways with a scope for admission avoidance. They remain safe and relevant to their purpose, transforming complex clinical presentations into tangible numbers, aiding objective decision making.
Trial registration: NHS HRA registration and REC approval (20/HRA/2344, IRAS ID 283888).
Changes in in-hospital mortality in the first wave of COVID-19: a multicentre prospective observational cohort study using the WHO Clinical Characterisation Protocol UK
