LMIC-PRIEST: Derivation and validation of a clinical severity score for acutely ill adults with suspected COVID-19 in a middle-income setting

BackgroundUneven vaccination and less resilient health care systems mean hospitals in LMICs are at risk of being overwhelmed during periods of increased COVID-19 infection. Risk-scores proposed for rapid triage of need for admission from the emergency department (ED) have been developed in higher-income settings during initial waves of the pandemic. MethodsRoutinely collected data for public hospitals in the Western Cape, South Africa from the 27th August 2020 to 11th March 2022 were used to derive a cohort of 446,084 ED patients with suspected COVID-19. The primary outcome was death or ICU admission at 30 days. The cohort was divided into derivation and Omicron variant validation sets. We developed the LMIC-PRIEST score based on the coefficients from multivariable analysis in the derivation cohort and existing triage practices. We externally validated accuracy in the Omicron period and a UK cohort. ResultsWe analysed 305,564, derivation 140,520 Omicron and 12,610 UK validation cases. Over 100 events per predictor parameter were modelled. Multivariable analyses identified eight predictor variables retained across models. We used these findings and clinical judgement to develop a score based on South African Triage Early Warning Scores and also included age, sex, oxygen saturation, inspired oxygen, diabetes and heart disease. The LMIC-PRIEST score achieved C-statistics: 0.82 (95% CI: 0.82 to 0.83) development cohort; 0.79 (95% CI: 0.78 to 0.80) Omicron cohort; and 0.79 (95% CI: 0.79 to 0.80) UK cohort. Differences in prevalence of outcomes led to imperfect calibration in external validation. However, use of the score at thresholds of three or less would allow identification of very low-risk patients (NPV [≥]0.99) who could be rapidly discharged using information collected at initial assessment. ConclusionThe LMIC-PRIEST score shows good discrimination and high sensitivity at lower thresholds and can be used to rapidly identify low-risk patients in LMIC ED settings. What is already known on this subjectO_LIUneven vaccination in low- and middle-income countries (LMICs) coupled with less resilient health care provision mean that emergency health care systems in LMICs may still be at risk of being overwhelmed during periods of increased COVID-19 infection. C_LIO_LIRisk-stratification scores may help rapidly triage need for hospitalisation. However, those proposed for use in the ED for patients with suspected COVID-19 have been developed and validated in high-income settings. C_LI What this study addsO_LIThe LMIC-PRIEST score has been robustly developed using a large routine dataset from the Western Cape, South Africa and is directly applicable to existing triage practices in LMICs. C_LIO_LIExternal validation across both income settings and COVID-19 variants showed good discrimination and high sensitivity (at lower thresholds) to a composite outcome indicating need for inpatient admission from the ED C_LI How this study might affect research, practice or policyO_LIUse of the LMIC-PRIEST score at thresholds of three or less would allow identification of very low-risk patients (negative predictive value [≥]0.99) across all settings assessed C_LIO_LIDuring periods of increased demand, this could allow the rapid identification and discharge of patients from the ED using information collected at initial assessment. C_LI

Prognostic accuracy of triage tools for adults with suspected COVID-19 in a middle-income setting: an observational cohort study

Study ObjectiveTools proposed to triage acuity in suspected COVID-19 in the ED have been derived and validated in higher-income settings during early waves of the pandemic. We estimated the accuracy of seven risk-stratification tools recommended to predict severe illness in the Western Cape, South Africa. MethodsAn observational cohort study using routinely collected data from EDs across the Western Cape, from the 27th of August 2020 to 11th March 2022 was conducted to assess performance of the PRIEST tool, NEWS2, TEWS, the WHO algorithm, CRB-65, Quick COVID-19 Severity Index and PMEWS in suspected COVID-19. The primary outcome was death or ICU admission. ResultsOf 446,084 patients, 15,397 patients (3.45%, 95% CI:34% to 35.1%) experienced the primary outcome. Clinical decision-making for inpatient admission achieved a sensitivity of 0.77 (95% CI 0.76 to 0.78), specificity 0.88 (95% CI 0.87 to 0.88) and the negative predictive value (NPV) 0.99 (95% CI 0.99 to 0.99). NEWS2, PMEWS and PRIEST tool algorithm identified patients at risk of adverse outcomes at recommended cut-offs with moderate sensitivity (>0.8) and specificity ranging from 0.47 (NEWS2) to 0.65 (PRIEST tool). Use of the tools at recommended thresholds would have more than doubled admissions with only a 0.01% reduction in false negative triage. ConclusionUse of the PRIEST score, NEWS2 and PMEWS at a threshold of a point higher would achieve similar accuracy to current clinical admission decision, with possible gains in transparency and speed of decision-making.

A study protocol for a retrospective cohort study and interrupted time series analysis to assess the effect of the COVID-19 pandemic on major trauma presentations and patient outcomes in English hospitals.

A protocol for a retrospective cohort study and interrupted time series analysis to investigate the effect of successive COVID related "lockdown" restrictions on major trauma presentations and patient outcomes in English hospitals. The study specifically aims to assess: 1) The impact of successive "lockdowns" on the volume, demographics, injury mechanism, severity, treatment and outcomes of major trauma in England. 2) If the implementation of "lockdowns" affected major trauma related mortality. A patient cohort will be derived from the Trauma and Audit Research Network (TARN) database, for all trauma receiving hospitals in England, between 1st of January 2017 to 1st of September 2021. This period encompasses two national "lockdown" periods (23rd March 2020 to 29th June 2020 and 2nd Nov 2020 to 16th May 2021) in England. A time series will be used to illustrate changes in the volume and mechanism of injury associated with successive "lockdowns". Demographic characteristics and features of the clinical care pathways will be compared during the "lockdown" and equivalent pre-COVID periods. To specifically assess if there were any changes in risk adjusted mortality associated with the "lockdowns" interrupted time series analysis will be conducted.

Accuracy of emergency medical service telephone triage of need for an ambulance response in suspected COVID-19: An observational cohort study

BackgroundEmergency Medical Services (EMS) have experienced surges in demand as the COVID-19 pandemic has progressed with ambulances services in the UK declaring major incidents due to the risk of care being compromised. COVID-19 specific EMS telephone triage tools have been introduced to help manage demand. There has been no previous evaluation of the accuracy of EMS telephone triage in identifying patients with suspected COVID-19 at risk of serious adverse outcome. We aimed to assess accuracy of EMS telephone triage in identifying patients who need an EMS response and identify factors which affect triage accuracy. MethodPatients who made an emergency call to Yorkshire Ambulance Service between 2nd April and 29th June 2020 and were assessed using an AMPDS pandemic pathway for suspected COVID-19 were linked to Office for National Statistics death registration data, hospital and general practice electronic health care data collected by NHS Digital. Accuracy of decision to dispatch an ambulance was assessed in terms of death or need for organ support at 30 days from the first 999 call. Multivariable logistic regression was used to identify factors associated with false negative and false positive triage. ResultsOf 12, 653 callers included in the study population, 11.1% experienced the primary composite adverse outcome. Using the triage pathway, 16% of callers did not receive an emergency response and they had a lower risk (3.5%) of the primary outcome. Ambulances were dispatched to 4, 230 callers (33.4%) who were not subsequently conveyed to hospital and did not experience the primary outcome (false positive triage). Multivariable modelling found older age and presence of pre-existing respiratory disease were significant predictors of false positive triage. ConclusionEMS telephone triage avoided 16% of calls receiving an emergency ambulance, of whom 3.5% died or needed organ support by 30 days. Telephone triage can therefore reduce the burden of EMS responses but with the cost of a small proportion of patients who do not receive an initial emergency response deteriorating. Research is needed to identify the appropriate balance between over- and under-triage

Prognostic accuracy of triage tools for adults with suspected COVID-19 in a pre-hospital setting: an observational cohort study

Study ObjectiveTools proposed to triage patient acuity in COVID-19 infection have only been validated in hospital populations. We estimated the accuracy of five risk-stratification tools recommended to predict severe illness and compare accuracy to existing clinical decision-making in a pre-hospital setting. MethodsAn observational cohort study using linked ambulance service data for patients attended by EMS crews in the Yorkshire and Humber region of England between 18th March 2020 and 29th June 2020 was conducted to assess performance of the PRIEST tool, NEWS2, the WHO algorithm, CRB-65 and PMEWS in patients with suspected COVID-19 infection. The primary outcome was death or need for organ support. ResultsOf 7549 patients in our cohort, 17.6% (95% CI:16.8% to 18.5%) experienced the primary outcome. The NEWS2, PMEWS, PRIEST tool and WHO algorithm identified patients at risk of adverse outcomes with a high sensitivity (>0.95) and specificity ranging from 0.3 (NEWS2) to 0.41 (PRIEST tool). The high sensitivity of NEWS2 and PMEWS was achieved by using lower thresholds than previously recommended. On index assessment, 65% of patients were transported to hospital and EMS decision to transfer patients achieved a sensitivity of 0.84 (95% CI 0.83 to 0.85) and specificity of 0.39 (95% CI 0.39 to 0.40). ConclusionUse of NEWS2, PMEWS, PRIEST tool and WHO algorithm could improve sensitivity of EMS triage of patients with suspected COVID-19 infection. Use of the PRIEST tool would improve sensitivity of triage without increasing the number of patients conveyed to hospital.

Accuracy of telephone triage for predicting adverse outcome in suspected COVID-19: An observational cohort study

ObjectiveTo assess accuracy of telephone triage in identifying patients who need emergency care amongst those with suspected COVID-19 infection and identify factors which affect triage accuracy. DesignObservational cohort study SettingCommunity telephone triage in the Yorkshire and Humber, Bassetlaw, North Lincolnshire and North East Lincolnshire region. Participants40, 261 adults who contacted NHS 111 telephone triage services provided by Yorkshire Ambulance Service NHS Trust between the 18th March 2020 and 29th June 2020 with symptoms indicating possible COVID-19 infection were linked to Office for National Statistics death registration data, hospital and general practice electronic health care data collected by NHS Digital. OutcomeAccuracy of triage disposition (self-care/non-urgent clinical assessment versus ambulance dispatch/urgent clinical assessment) was assessed in terms of death or need for organ support at 30, 7 and 3 days from first contact with the telephone triage service. ResultsCallers had a 3% (1, 200/40, 261) risk of adverse outcome. Telephone triage recommended self-care or non-urgent assessment for 60% (24, 335/40, 261), with a 1.3% (310/24, 335) risk of subsequent adverse outcome. Telephone triage had 74.2% sensitivity (95% CI: 71.6 to 76.6%) and 61.5% specificity (61% to 62%) for adverse outcomes at 30 days from first contact. Multivariable analysis suggested some co-morbidities (such as chronic respiratory disease) may be over-estimated as predictors of adverse outcome, while the association of diabetes with adverse outcome may be under-estimated. Repeat contact with the service appears to be an important under recognised predictor of adverse outcomes with both 2 contacts (OR 1.77 95% CI: 1.14 to 2.75) and 3 or more contacts (OR 4.02 95% CI: 1.68 to 9.65) associated with clinical deterioration when not provided with an ambulance or urgent clinical assessment. ConclusionPatients advised to self-care or receive non-urgent clinical assessment had a small but non-negligible risk of serious clinical deterioration. The sensitivity and specificity of telephone triage was comparable to other tools used to triage patient acuity in emergency and urgent care. Repeat contact with telephone services needs recognition as an important predictor of subsequent adverse outcomes. What is already known on this topicO_LITelephone triage has been used to divert patients with suspected COVID-19 to self care or for non-urgent clinical assessments, and thereby help mitigate the risk of health services being overwhelmed by patients who require no speficic treatment. C_LIO_LIConcerns have been raised that telephone triage may not be sufficiently accurate in identifying need for emergency care. However, no previous evaluation of accuracy of telephone triage in patients with suspected COVID-19 infection has been completed. C_LI What this study addsO_LIPatients advised to self care or receive non-urgent clinical assessment had a small but non-negligible risk of deterioration and significant adverse outcomes. C_LIO_LITelephone triage has comparable performance to methods used to triage patient acuity in other emergency and urgent care settings. C_LIO_LIAccuracy of triage may be improved by better recognition of multiple contact with services as a predictor of adverse outcomes. C_LI

Derivation and validation of a triage tool for acutely ill adults with suspected COVID-19: The PRIEST observational cohort study

ObjectivesWe aimed to derive and validate a triage tool, based on clinical assessment alone, for predicting adverse outcome in acutely ill adults with suspected COVID-19 infection. MethodsWe undertook a mixed prospective and retrospective observational cohort study in 70 emergency departments across the United Kingdom (UK). We collected presenting data from 22445 people attending with suspected COVID-19 between 26 March 2020 and 28 May 2020. The primary outcome was death or organ support (respiratory, cardiovascular, or renal) by record review at 30 days. We split the cohort into derivation and validation sets, developed a clinical score based on the coefficients from multivariable analysis using the derivation set, and the estimated discriminant performance using the validation set. ResultsWe analysed 11773 derivation and 9118 validation cases. Multivariable analysis identified that age, sex, respiratory rate, systolic blood pressure, oxygen saturation/inspired oxygen ratio, performance status, consciousness, history of renal impairment, and respiratory distress were retained in analyses restricted to the ten or fewer predictors. We used findings from multivariable analysis and clinical judgement to develop a score based on the NEWS2 score, age, sex, and performance status. This had a c-statistic of 0.80 (95% confidence interval 0.79-0.81) in the validation cohort and predicted adverse outcome with sensitivity 0.98 (0.97-0.98) and specificity 0.34 (0.34-0.35) for scores above four points. ConclusionA clinical score based on NEWS2, age, sex, and performance status predicts adverse outcome with good discrimination in adults with suspected COVID-19 and can be used to support decision-making in emergency care. RegistrationISRCTN registry, ISRCTN28342533, http://www.isrctn.com/ISRCTN28342533

Prognostic accuracy of emergency department triage tools for adults with suspected COVID-19: The PRIEST observational cohort study

ObjectivesThe World Health Organisation (WHO) and National Institute for Health and Care Excellence (NICE) recommend various triage tools to assist decision-making for patients with suspected COVID-19. We aimed to estimate the accuracy of triage tools for predicting severe illness in adults presenting to the emergency department (ED) with suspected COVID-19 infection. MethodsWe undertook a mixed prospective and retrospective observational cohort study in 70 EDs across the United Kingdom (UK). We collected data from people attending with suspected COVID-19 between 26 March 2020 and 28 May 2020, and used presenting data to determine the results of assessment with the following triage tools: the WHO algorithm, NEWS2, CURB-65, CRB-65, PMEWS and the swine flu adult hospital pathway (SFAHP). We used 30-day outcome data (death or receipt of respiratory, cardiovascular or renal support) to determine prognostic accuracy for adverse outcome. ResultsWe analysed data from 20892 adults, of whom 4672 (22.4%) died or received organ support (primary outcome), with 2058 (9.9%) receiving organ support and 2614 (12.5%) dying without organ support (secondary outcomes). C-statistics for the primary outcome were: CURB-65 0.75; CRB-65 0.70; PMEWS 0.77; NEWS2 (score) 0.77; NEWS2 (rule) 0.69; SFAHP (6-point) 0.70; SFAHP (7-point) 0.68; WHO algorithm 0.61. All triage tools showed worse prediction for receipt of organ support and better prediction for death without organ support. At the recommended threshold, PMEWS and the WHO criteria showed good sensitivity (0.96 and 0.95 respectively), at the expense of specificity (0.31 and 0.27 respectively). NEWS2 showed similar sensitivity (0.96) and specificity (0.28) when a lower threshold than recommended was used. ConclusionCURB-65, PMEWS and NEWS2 provide good but not excellent prediction for adverse outcome in suspected COVID-19, and predicted death without organ support better than receipt of organ support. PMEWS, the WHO criteria and NEWS2 (using a lower threshold than usually recommended) provide good sensitivity at the expense of specificity. RegistrationISRCTN registry, ISRCTN28342533, http://www.isrctn.com/ISRCTN28342533

Prognostic accuracy of emergency department triage tools for children with suspected COVID-19: The PRIEST observational cohort study

ObjectivesEmergency department clinicians can use triage tools to predict adverse outcome and support management decisions for children presenting with suspected COVID-19. We aimed to estimate the accuracy of triage tools for predicting severe illness in children presenting to the emergency department (ED) with suspected COVID-19 infection. MethodsWe undertook a mixed prospective and retrospective observational cohort study in 44 EDs across the United Kingdom (UK). We collected data from children attending with suspected COVID-19 between 26 March 2020 and 28 May 2020, and used presenting data to determine the results of assessment using the WHO algorithm, swine flu hospital pathway for children (SFHPC), Paediatric Observation Priority Score (POPS) and Childrens Observation and Severity Tool (COAST). We recorded 30-day outcome data (death or receipt of respiratory, cardiovascular or renal support) to determine prognostic accuracy for adverse outcome. ResultsWe collected data from 1530 children, including 26 (1.7%) with an adverse outcome. C-statistics were 0.80 (95% confidence interval 0.73-0.87) for the WHO algorithm, 0.80 (0.71-0.90) for POPS, 0.76 (0.67-0.85) for COAST, and 0.71 (0.59-0.82) for SFHPC. Using pre-specified thresholds, the WHO algorithm had the highest sensitivity (0.85) and lowest specificity (0.75), but POPS and COAST could optimise sensitivity (0.96 and 0.92 respectively) at the expense of specificity (0.25 and 0.38 respectively) by using a threshold of any score above zero instead of the pre-specified threshold. ConclusionExisting triage tools have good but not excellent prediction for adverse outcome in children with suspected COVID-19. POPS and COAST could achieve an appropriate balance of sensitivity and specificity for supporting decisions to discharge home by considering any score above zero to be positive. RegistrationISRCTN registry, ISRCTN28342533, http://www.isrctn.com/ISRCTN28342533

Characterisation of 22446 patients attending UK emergency departments with suspected COVID-19 infection: Observational cohort study

BackgroundHospital emergency departments play a crucial role in the Initial management of suspected COVID-19 infection. We aimed to characterise patients attending emergency departments with suspected COVID-19, including subgroups based on sex, ethnicity and COVID-19 test results. MethodsWe undertook a mixed prospective and retrospective observational cohort study in 70 emergency departments across the United Kingdom (UK). We collected presenting data from 22446 people attending with suspected COVID-19 between 26 March 2020 and 28 May 2020. Outcomes were admission to hospital, COVID-19 result, organ support (respiratory, cardiovascular or renal), and death, by record review at 30 days. ResultsAdults were acutely unwell (median NEWS2 score 4) and had high rates of admission (67.1%), COVID-19 positivity (31.2%), organ support (9.8%) and death (15.9%). Children had much lower rates of admission (27.4%), COVID-19 positivity (1.2%), organ support (1.4%) and death (0.3%). Adult men and women presented in similar numbers (10210 versus 10506), but men were more likely to be admitted (72.9% v 61.4%), require organ support (12.2% v 7.7%) and die (18.7% v 13.3%). Black or Asian adults tended to be younger than White adults (median age 54, 50 and 67 years), were less likely to be admitted (60.8%, 57.3%, 69.6%) or die (11.9%, 11.2%, 16.8%), but were more likely to require organ support (15.9%, 14.3%, 8.9%) or have a positive COVID-19 test (40.8%, 42.1%, 30.0%). Adults admitted with confirmed COVID-19 had similar age and comorbidities (except chronic lung disease) to those who did not have COVID-19 confirmed, but were much more likely to need organ support (22.2% v 8.9%) or die (32.7% v 15.9%). ConclusionsImportant differences exist between patient groups presenting to the emergency department with suspected COVID-19. People with confirmed COVID-19 have a poor prognosis, compared with similar emergency admissions without confirmed COVID-19. RegistrationISRCTN registry, ISRCTN56149622, http://www.isrctn.com/ISRCTN28342533

Post-exertion oxygen saturation as a prognostic factor for adverse outcome in patients attending the emergency department with suspected COVID-19: Observational cohort study

BackgroundMeasurement of post-exertion oxygen saturation has been proposed to assess illness severity in suspected COVID-19 infection. We aimed to determine the accuracy of post-exertional oxygen saturation for predicting adverse outcome in suspected COVID-19. MethodsWe undertook an observational cohort study across 70 emergency departments during first wave of the COVID-19 pandemic in the United Kingdom. We collected data prospectively, using a standardised assessment form, and retrospectively, using hospital records, from patients with suspected COVID-19, and reviewed hospital records at 30 days for adverse outcome (death or receiving organ support). Patients with post-exertion oxygen saturation recorded were selected for this analysis. ResultsWe analysed data from 817 patients with post-exertion oxygen saturation recorded after excluding 54 in whom measurement appeared unfeasible. The c-statistic for post-exertion change in oxygen saturation was 0.589 (95% confidence interval 0.465 to 0.713), and the positive and negative likelihood ratios of a 3% or more desaturation were respectively 1.78 (1.25 to 2.53) and 0.67 (0.46 to 0.98). Multivariable analysis showed that post-exertion oxygen saturation was not a significant predictor of adverse outcome when baseline clinical assessment was taken into account (p=0.368). Secondary analysis excluding patients in whom post-exertion measurement appeared inappropriate resulted in a c-statistic of 0.699 (0.581 to 0.817), likelihood ratios of 1.98 (1.26 to 3.10) and 0.61 (0.35 to 1.07), and some evidence of additional prognostic value on multivariable analysis (p=0.019). ConclusionsPost-exertion oxygen saturation provides modest prognostic information in the assessment of patients attending the emergency department with suspected COVID-19. RegistrationISRCTN registry, ISRCTN56149622, http://www.isrctn.com/ISRCTN28342533 Key messagesWhat is already known on this subject? O_LIPost exertional decrease in oxygen saturation can be used to predict prognosis in chronic lung diseases C_LIO_LIPost exertional desaturation has been proposed as a way of predicting adverse outcome in people with suspected COVID-19 C_LI What this study adds: O_LIPost-exertion oxygen saturation provides modest prognostic information in the assessment of patients attending the emergency department with suspected COVID-19 C_LI