Variable importance analysis with interpretable machine learning for fair risk prediction.

Machine learning (ML) methods are increasingly used to assess variable importance, but such black box models lack stability when limited in sample sizes, and do not formally indicate non-important factors. The Shapley variable importance cloud (ShapleyVIC) addresses these limitations by assessing variable importance from an ensemble of regression models, which enhances robustness while maintaining interpretability, and estimates uncertainty of overall importance to formally test its significance. In a clinical study, ShapleyVIC reasonably identified important variables when the random forest and XGBoost failed to, and generally reproduced the findings from smaller subsamples (n = 2500 and 500) when statistical power of the logistic regression became attenuated. Moreover, ShapleyVIC reasonably estimated non-significant importance of race to justify its exclusion from the final prediction model, as opposed to the race-dependent model from the conventional stepwise model building. Hence, ShapleyVIC is robust and interpretable for variable importance assessment, with potential contribution to fairer clinical risk prediction.

Machine learning prediction of refractory ventricular fibrillation in out-of-hospital cardiac arrest using features available to EMS.

Background: Shock-refractory ventricular fibrillation (VF) or ventricular tachycardia (VT) is a treatment challenge in out-of-hospital cardiac arrest (OHCA). This study aimed to develop and validate machine learning models that could be implemented by emergency medical services (EMS) to predict refractory VF/VT in OHCA patients. Methods: This was a retrospective study examining adult non-traumatic OHCA patients brought into the emergency department by Singapore EMS from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Data from April 2010 to March 2020 were extracted for this study. Refractory VF/VT was defined as VF/VT persisting or recurring after at least one shock. Features were selected based on expert clinical opinion and availability to dispatch prior to arrival at scene. Multivariable logistic regression (MVR), LASSO and random forest (RF) models were investigated. Model performance was evaluated using receiver operator characteristic (ROC) area under curve (AUC) analysis and calibration plots. Results: 20,713 patients were included in this study, of which 860 (4.1%) fulfilled the criteria for refractory VF/VT. All models performed comparably and were moderately well-calibrated. ROC-AUC were 0.732 (95% CI, 0.695 - 0.769) for MVR, 0.738 (95% CI, 0.701 - 0.774) for LASSO, and 0.731 (95% CI, 0.690 - 0.773) for RF. The shared important predictors across all models included male gender and public location. Conclusion: The machine learning models developed have potential clinical utility to improve outcomes in cases of refractory VF/VT OHCA. Prediction of refractory VF/VT prior to arrival at patient's side may allow for increased options for intervention both by EMS and tertiary care centres.

Assertive community treatment for high-utilizing alcohol misuse patients: a before-and-after cohort study protocol.

BACKGROUND: The challenge posed by Alcohol-Related Frequent Attenders (ARFAs) in Emergency Departments (EDs) is growing in Singapore, marked by limited engagement with conventional addiction treatment pathways. Recognizing this gap, this study aims to explore the potential benefits of Assertive Community Treatment (ACT) - an innovative, community-centered, harm-reduction strategy-in mitigating the frequency of ED visits, curbing Emergency Medical Services (EMS) calls, and uplifting health outcomes across a quartet of Singaporean healthcare institutions. METHODS: Employing a prospective before-and-after cohort design, this investigation targeted ARFAs aged 21 years and above, fluent in English or Mandarin. Eligibility was determined by a history of at least five ED visits in the preceding year, with no fewer than two due to alcohol-related issues. The study contrasted health outcomes of patients integrated into the ACT care model versus their experiences under the exclusive provision of standard emergency care across Hospitals A, B, C and D. Following participants for half a year post-initial assessment, the evaluation metrics encompassed socio-demographic factors, ED, and EMS engagement frequencies, along with validated health assessment tools, namely Christo Inventory for Substance-misuse Services (CISS) scores, University of California, Los Angeles (UCLA) Loneliness scores, and Centre for Epidemiologic Studies Depression Scale Revised (CESD-R-10) scores. DISCUSSION: Confronted with intricate socio-economic and medical challenges, the ARFA cohort often grapples with heightened vulnerabilities in relation to alcohol misuse. Pioneering the exploration of ACT's efficacy with ARFAs in a Singaporean context, our research is anchored in a patient-centered approach, designed to comprehensively address these multifaceted clinical profiles. While challenges, like potential high attrition rates and sporadic data collection, are anticipated, the model's prospective contribution towards enhancing patient well-being and driving healthcare efficiencies in Singapore is substantial. Our findings have the potential to reshape healthcare strategies and policy recommendations. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04447079. Initiated on 25 June 2020.

Increasing neurologically intact survival after out-of-hospital cardiac arrest among elderly: Singapore Experience.

Objectives: With more elderly presenting with Out-of-Hospital Cardiac Arrests (OHCAs) globally, neurologically intact survival (NIS) should be the aim of resuscitation. We aimed to study the trend of OHCA amongst elderly in a large Asian registry to identify if age is independently associated with NIS and factors associated with NIS. Methods: All adult OHCAs aged ≥18 years attended by emergency medical services (EMS) from April 2010 to December 2019 in Singapore was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Cases pronounced dead at scene, non-EMS transported, traumatic OHCAs and OHCAs in ambulances were excluded. Patient characteristics and outcomes were compared across four age categories (18-64, 65-79, 80-89, ≥90). Multivariable logistic regression analysis determined the factors associated with NIS. Results: 19,519 eligible cases were analyzed. OHCA incidence increased with age almost doubling in octogenarians (from 312/100,000 in 2011 to 652/100,000 in 2019) and tripling in those ≥90 years (from 458/100,000 in 2011 to 1271/100,000 in 2019). The proportion of patients with NIS improved over time for the 18-64, 65-79- and 80-89-years age groups, with the greatest improvement in the youngest group. NIS decreased with each increasing year of age and minute of response time. NIS increased in the arrests of presumed cardiac etiology, witnessed and bystander CPR. Conclusions: Survival with good outcomes has increased even amongst the elderly. Regardless of age, NIS is possible with good-quality CPR, highlighting its importance. End-of-life planning is a complex yet necessary decision that requires qualitative exploration with elderly, their families and care providers.

Comparing outcomes of out-of-hospital cardiac arrest patients with initial shockable rhythm in Singapore and Osaka using population-based databases.

BACKGROUND: Previous research indicated outcomes among refractory out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm were different in Singapore and Osaka, Japan, possibly due to the differences in access to extracorporeal cardiopulmonary resuscitation. However, this previous study had a risk of selection bias. To address this concern, this study aimed to evaluate the outcomes between Singapore and Osaka for OHCA patients with initial shockable rhythm using only population-based databases. METHODS: This was a secondary analysis of two OHCA population-based databases in Osaka and Singapore, including adult OHCA patients with initial shockable rhythm. A machine-learning-based prediction model was derived from the Osaka data (n = 3088) and applied to the PAROS-SG data (n = 2905). We calculated the observed-expected ratio (OE ratio) for good neurological outcomes observed in Singapore and the expected derived from the data in Osaka by dividing subgroups with or without prehospital ROSC. RESULTS: The one-month good neurological outcomes in Osaka and Singapore among patients with prehospital ROSC were 70% (791/1,125) and 57% (440/773), and among patients without prehospital ROSC were 10% (196/1963) and 2.8% (60/2,132). After adjusting patient characteristics, the outcome in Singapore was slightly better than expected from Osaka in patients with ROSC (OE ratio, 1.067 [95%CI 1.012 to 1.125]), conversely, it was worse than expected in patients without prehospital ROSC (OE ratio, 0.238 [95%CI 0.173 to 0.294]). CONCLUSION: This study showed the outcomes of OHCA patients without prehospital ROSC in Singapore were worse than expected derived from Osaka data even using population-based databases. (249/250 words).

Outcome assessment for out-of-hospital cardiac arrest patients in Singapore and Japan with initial shockable rhythm.

BACKGROUND: Singapore and Osaka in Japan have comparable population sizes and prehospital management; however, the frequency of ECPR differs greatly for out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm. Given this disparity, we hypothesized that the outcomes among the OHCA patients with initial shockable rhythm in Singapore were different from those in Osaka. The aim of this study was to evaluate the outcomes of OHCA patients with initial shockable rhythm in Singapore compared to the expected outcomes derived from Osaka data using machine learning-based prediction models. METHODS: This was a secondary analysis of two OHCA databases: the Singapore PAROS database (SG-PAROS) and the Osaka-CRITICAL database from Osaka, Japan. This study included adult (18-74 years) OHCA patients with initial shockable rhythm. A machine learning-based prediction model was derived and validated using data from the Osaka-CRITICAL database (derivation data 2012-2017, validation data 2018-2019), and applied to the SG-PAROS database (2010-2016 data), to predict the risk-adjusted probability of favorable neurological outcomes. The observed and expected outcomes were compared using the observed-expected ratio (OE ratio) with 95% confidence intervals (CI). RESULTS: From the SG-PAROS database, 1,789 patients were included in the analysis. For OHCA patients who achieved return of spontaneous circulation (ROSC) on hospital arrival, the observed favorable neurological outcome was at the same level as expected (OE ratio: 0.905 [95%CI: 0.784-1.036]). On the other hand, for those who had continued cardiac arrest on hospital arrival, the outcomes were lower than expected (shockable rhythm on hospital arrival, OE ratio: 0.369 [95%CI: 0.258-0.499], and nonshockable rhythm, OE ratio: 0.137 [95%CI: 0.065-0.235]). CONCLUSION: This observational study found that the outcomes for patients with initial shockable rhythm but who did not obtain ROSC on hospital arrival in Singapore were lower than expected from Osaka. We hypothesize this is mainly due to differences in the use of ECPR.

Impact of time-to-compression on out-of-hospital cardiac arrest survival outcomes: A national registry study.

OBJECTIVE: We aimed to quantify the association of no-flow interval in out-of-hospital cardiac arrests (OHCA) with the odds of neurologically favorable survival and survival to hospital discharge/ 30th day. Our secondary aim was to explore futility thresholds to guide clinical decisions, such as prehospital termination of resuscitation. METHODS: All OHCAs from 2012 to 2017 in Singapore were extracted. We examined the association between no-flow interval (continuous variable) and survival outcomes using univariate and multivariable logistic regressions. The primary outcome was survival with favorable cerebral performance (Glasgow-Pittsburgh Cerebral Performance Categories 1/2), the secondary outcome was survival to hospital discharge/ 30th day if not discharged. To determine futility thresholds, we plotted the adjusted probability of good neurological outcomes to no-flow interval. RESULTS: 12,771 OHCAs were analyzed. The per-minute adjusted OR when no-flow interval was incorporated as a continuous variable in the multivariable model was: good neurological function- aOR 0.98 (95%CI: 0.97-0.98); survival to discharge- aOR 0.98 (95%CI: 0.98-0.99). Taking the 1% futility of survival line gave a no-flow interval cutoff of 12 mins (NPV 99%, sensitivity 85% and specificity 42%) overall and 7.5 mins for witnessed arrests. CONCLUSION: We demonstrated that prolonged no-flow interval had a significant effect on lower odds of favorable neurological outcomes, with medical futility occurring when no-flow interval was >12 mins (>7.5 mins for witnessed arrest). Our study adds to the literature of the importance of early CPR and EMS response and provided a threshold beyond traditional 'down-times', which could aid clinical decisions in TOR or OHCA management.

Does witness type affect the chance of receiving bystander CPR in out-of-hospital cardiac arrest?

OBJECTIVES: The relationship between the bystander witness type and receipt of bystander CPR (BCPR) is not well understood. Herein we compared BCPR administration between family and non-family witnessed out-of-hospital cardiac arrest (OHCA). BACKGROUND: In many communities, interventions in the past decade have contributed to an increased receipt of BCPR, for example in Singapore from 15% to 60%. However, BCPR rates have plateaued despite sustained and ongoing community-based interventions, which may be related to gaps in education or training for various witness types. The purpose of this study was to investigate the association between witness type and BCPR administration. METHODS: Singapore data from 2010-2020 was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) network registry (n = 25,024). All adult, layperson witnessed, non-traumatic OHCAs were included in this study. RESULTS: Of 10,016 eligible OHCA cases, 6,895 were family witnessed and 3,121 were non-family witnessed. After adjustment for potential confounders, BCPR administration was less likely for non-family witnessed OHCA (OR 0.83, 95% CI 0.75, 0.93). After location stratification, non-family witnessed OHCAs were less likely to receive BCPR in residential settings (OR 0.75, 95% CI 0.66, 0.85). In non-residential settings, there was no statistically significant association between witness type and BCPR administration (OR 1.11, 95% CI 0.88, 1.39). Details regarding witness type and bystander CPR were limited. CONCLUSION: This study found differences in BCPR administration between family and non-family witnessed OHCA cases. Elucidation of witness characteristics may be useful to determine populations that would benefit most from CPR education and training.

Longitudinal Study Comparing Mental Health Outcomes in Frontline Emergency Department Healthcare Workers through the Different Waves of the COVID-19 Pandemic.

As countries transition from the COVID-19 pandemic to endemic status, healthcare systems continue to be under pressure. We aimed to quantify changes in depression, anxiety, stress and post-traumatic stress disorder (PTSD) between 3 cohorts (2020, 2021 and 2022) of our Emergency Department (ED) healthcare workers (HCWs) and those who had worked through all 3 phases of the pandemic; and identify factors associated with poorer mental health outcomes (MHOs). In this longitudinal single-centre study in Singapore, three surveys were carried out yearly (2020, 2021 and 2022) since the COVID-19 outbreak. Depression, anxiety and stress were measured using DASS-21, and PTSD was measured using IES-R. A total of 327 HCWs (90.1%) participated in 2020, 279 (71.5%) in 2021 and 397 (92.8%) in 2022. In 2022, ED HCWs had greater concerns about workload (Mean score ± SD: 2022: 4.81 ± 0.86, vs. 2021: 4.37 ± 0.89, vs. 2020: 4.04 ± 0.97) and perceived to have less workplace support (2022: 4.48 ± 0.76, vs. 2021: 4.66 ± 0.70, vs. 2020: 4.80 ± 0.69). There was overall worsening depression (27.5% in 2020, 29.7% in 2021 and 32.2% in 2022) and stress (12.2% in 2020, 14.0% in 2021 and 17.4% in 2022). Healthcare assistants as a subgroup had improving MHOs. ED HCWs who were female and had psychiatric history, were living with the elderly, and had concerns about their working environment, workload and infection had poorer MHOs. This study will guide us in refining existing and devising more focused interventions to further support our ED HCWs' wellbeing.

Nationwide study of the characteristics of frequent attenders with multiple emergency department attendance patterns.

INTRODUCTION: The burden of frequent attenders (FAs) of emergency departments (EDs) on healthcare resources is underestimated when single-centre analyses do not account for utilisation of multiple EDs by FAs. We aimed to quantify the extent of multiple ED use by FAs and to characterise FAs. METHODS: We reviewed nationwide ED attendance in Singapore data from 1 January 2006 to 31 December 2018 (13 years). FAs were defined as patients with ≥4 ED visits in any calendar year. Single ED FAs and multiple ED FAs were patients who attended a single ED exclusively and ≥2 distinct EDs within the year, respectively. Mixed ED FAs were patients who attended a mix of a single ED and multiple EDs in different calendar years. We compared the characteristics of FAs using multivariable logistic regression. RESULTS: We identified 200,130 (6.3%) FAs who contributed to1,865,704 visits (19.6%) and 2,959,935 (93.7%) non-FAs who contributed to 7,671,097 visits (80.4%). After missing data were excluded, the study population consisted of 199,283 unique FAs. Nationwide-linked data identified an additional 15.5% FAs and 29.7% FA visits, in addition to data from single centres. Multiple ED FAs and mixed ED FAs were associated with male sex, younger age, Malay or Indian ethnicity, multiple comorbidities, median triage class of higher severity, and a higher frequency of ED use. CONCLUSION: A nationwide approach is needed to quantify the national FA burden. The multiple comorbidities and higher frequency of ED use associated with FAs who visited multiple EDs and mixed EDs, compared to those who visited a single ED, suggested a higher level of ED burden in these subgroups of patients. The distinct characteristics and needs of each FA subgroup should be considered in future healthcare interventions to reduce FA burden.

Why Are Some Male Alcohol Misuse Disorder Patients High Utilisers of Emergency Health Services? An Asian Qualitative Study.

BACKGROUND: Certain alcohol misuse patients heavily utilise the Emergency Department (ED) and Emergency Medical Services (EMS) and may present with intoxication or long-term sequelae of alcohol misuse. Our study explored reasons for repeated ED/EMS utilisation and sought to understand perpetuating and protective factors for drinking. METHODS: Face-to-face semi-structured qualitative interviews were conducted. Participants were recruited from an ED in Singapore. Interviews were audio-recorded, transcribed verbatim and underwent manual thematic analysis. Emergent themes were independently reviewed for agreement. Data from medical records, interview transcripts, and field notes were triangulated for analysis. RESULTS: All participants were male (n = 20) with an average age of 55.6 years (SD = 8.86). Most were unemployed (75%), did not have tertiary education (75%), were divorced (55%), and had pre-existing psychiatric conditions (60%) and chronic cardiovascular conditions (75%). Reasons for utilisation included a perceived need due to symptoms, although sometimes it was bystanders who called the ambulance. ED/EMS was preferred due to the perceived higher quality and speed of care. Persistent drinking was attributed to social and environmental factors, and as a coping mechanism for stressors. Rehabilitation programs and meaningful activities reduced drinking tendencies. CONCLUSION: ED/EMS provide sought-after services for alcohol misuse patients, resulting in high utilisation. Social and medical intervention could improve drinking behaviours and decrease overall ED/EMS utilisation.

Inter-hospital trends of post-resuscitation interventions and outcomes of out-of-hospital cardiac arrest in Singapore.

INTRODUCTION: Hospital-based resuscitation interventions, such as therapeutic temperature management (TTM), emergency percutaneous coronary intervention (PCI) and extracorporeal membrane oxygenation (ECMO) can improve outcomes in out-of-hospital cardiac arrest (OHCA). We investigated post-resuscitation interventions and hospital characteristics on OHCA outcomes across public hospitals in Singapore over a 9-year period. METHODS: This was a prospective cohort study of all OHCA cases that presented to 6 hospitals in Singapore from 2010 to 2018. Data were extracted from the Pan-Asian Resuscitation Outcomes Study Clinical Research Network (PAROS CRN) registry. We excluded patients younger than 18 years or were dead on arrival at the emergency department. The outcomes were 30-day survival post-arrest, survival to admission, and neurological outcome. RESULTS: The study analysed 17,735 cases. There was an increasing rate of provision of TTM, emergency PCI and ECMO (P<0.001) in hospitals, and a positive trend of survival outcomes (P<0.001). Relative to hospital F, hospitals B and C had lower provision rates of TTM (≤5.2%). ECMO rate was consistently <1% in all hospitals except hospital F. Hospitals A, B, C, E had <6.5% rates of provision of emergency PCI. Relative to hospital F, OHCA cases from hospitals A, B and C had lower odds of 30-day survival (adjusted odds ratio [aOR]<1; P<0.05 for hospitals A-C) and lower odds of good neurological outcomes (aOR<1; P<0.05 for hospitals A-C). OHCA cases from academic hospitals had higher odds ratio (OR) of 30-day survival (OR 1.3, 95% CI 1.1-1.5) than cases from hospitals without an academic status. CONCLUSION: Post-resuscitation interventions for OHCA increased across all hospitals in Singapore from 2010 to 2018, correlating with survival rates. The academic status of hospitals was associated with improved survival.

Validation of the CaRdiac Arrest Survival Score (CRASS) for predicting good neurological outcome after out-of-hospital cardiac arrest in an Asian emergency medical service system.

BACKGROUND: Survival with favorable neurological outcomes is an important indicator of successful resuscitation in out-of-hospital cardiac arrest (OHCA). We sought to validate the CaRdiac Arrest Survival Score (CRASS), derived using data from the German Resuscitation Registry, in predicting the likelihood of good neurological outcomes after OHCA in Singapore. METHODS: We conducted a retrospective population-based validation study among EMS-attended OHCA patients (≥18 years) in Singapore, using data from the prospective Pan-Asian Resuscitation Outcomes Study registry. Good neurological outcome was defined as a cerebral performance category of 1 or 2. To evaluate the CRASS score in light of the difference in patient characteristics, we used the default constant coefficient (0.8) and the adjusted coefficient (0.2) to calculate the probability of good neurological outcomes. RESULTS: Out of 11,404 analyzed patients recruited between April 2010 and December 2018, 260 had good and 11,144 had poor neurological function. The CRASS score demonstrated good discrimination, with an area under the curve of 0.963 (95% confidence interval: 0.952-0.974). Using the default constant coefficient of 0.8, the CRASS score consistently overestimated the predicted probability of a good outcome. Following adjustment of the coefficient to 0.2, the CRASS score showed improved calibration. CONCLUSION: CRASS demonstrated good discrimination and moderate calibration in predicting favorable neurological outcomes in the validation Singapore cohort. Our study established a good foundation for future large-scale, cross-country validations of the CRASS score in diverse sociocultural, geographical, and clinical settings.

Nationwide Alcohol-related visits In Singapore's Emergency departments (NAISE): A retrospective population-level study from 2007 to 2016.

INTRODUCTION: Excessive alcohol consumption is associated with increased morbidity and mortality, and its societal impact is substantial. The Nationwide Alcohol-related visits In Singapore Emergency departments study aims to characterise trends in ED visits involving acute and chronic alcohol consumption between 2007 and 2016. METHODS: Data from the Singapore Ministry of Health, comprising all ED visits in Singapore from 2007 to 2016, were used. The data were aggregated by year and analysed for changes in prevalence and rates of ED visits for acute and chronic alcohol consumption, broken down by age, gender and ethnicity. RESULTS: Over the study period, the number of ED visits involving alcohol consumption increased 98.3%, from 2236 in 2007 to 4433 in 2016. During the same period, the rate per 100 000 population increased 62.4% from 48.7 to 79.1, and total ED-related costs rose by 140%, from 528 680 to 1 269 638 SGD. The increase in alcohol-related visits rates and costs was higher than non-alcohol-related visits rates and costs, which increased by 12.1% and 115% respectively. While trends in acute and chronic alcohol-related ED visits stayed stable amongst women, they rose substantially in men. Older men aged 50-69 show the highest rates and rate of increase for both acute and chronic alcohol-related ED visits. DISCUSSION AND CONCLUSIONS: Alcohol-related visits contributed disproportionately to the increasing number of ED visits in Singapore between 2007 and 2016. Older men form the demographic with the highest rates and increase in rates of alcohol-related ED visits and form a potential group for targeted intervention.

The association between mode of transport and out-of-hospital cardiac arrest outcomes in Singapore.

OBJECTIVE: We aimed to examine the survival outcomes of out-of-hospital cardiac arrest (OHCA) patients, stratified by the transportation modes to the Emergency Department (ED). METHODS: This was a retrospective analysis of Singapore's Pan-Asian Resuscitation Outcomes Study registry from Apr 2010-Dec 2017. The primary outcome was survival to discharge or 30 days post-arrest. Secondary outcomes were the return of spontaneous circulation (ROSC) rate and neurological outcomes. A subgroup analysis was performed for OHCA cases who collapsed enroute. RESULTS: A total of 15,376 cases were analysed. 15,129 (98.4%) were conveyed by Emergency Medical Services (EMS), 111 (0.72%) by private ambulance, 106 (0.69%) by own transport and 30 (0.2%) by public transport. 80% of patients brought by public transport arrested enroute, compared to 48.1% by own transport, 25.2% by private ambulance and 2.5% in the EMS group. 33/120 (27.5%) of paediatric OHCA cases were brought in by non-EMS transport to paediatric hospitals. The EMS group had the lowest survival rate at 4.5%, compared to 13.3% for public transport, 11.3% for own transport and 14.4% for private ambulance. ROSC rate was statistically significant but not for neurological outcomes. For the subgroup analysis, there was no statistical difference for primary and secondary outcomes across the groups. CONCLUSION: In Singapore, most OHCA patients are conveyed by EMS to the hospital, but some OHCA patients still arrive via alternative transport without prehospital interventions like bystander CPR. More can be done to educate the public to recognise an impending cardiac arrest and to activate EMS early for such cases.

A new paradigm in management of frequent attenders to emergency departments with severe alcohol use disorder-A pilot study for assertive community treatment in Singapore.

Introduction: A majority of frequent users of emergency medical services in Singapore present with alcohol-related problems. These patients are known to engage poorly with traditional addiction services and frequently attend Emergency Departments (EDs) instead, resulting in high healthcare burden. Assertive Community Treatment (ACT) is an alternative intervention to traditional addiction management. ACT involves community visits with focus on holistic care and harm-reduction. Materials and methods: We conducted a prospective before-and-after cohort study at the major tertiary center for addiction disorders in Singapore. The main objective was to evaluate effectiveness of ACT in reducing alcohol-related attendances at EDs nationwide. Socio-demographics, alcohol-related ED attendances, and the Christo Inventory for Substance-misuse Services (CISS) scores were collected for the patients recruited from April 2018 to March 2019. Descriptive analyses and the Wilcoxon Signed-Rank Test were performed. Results: All 14 patients were male with a mean age of 55 years. There was a significant 45.3% reduction in average alcohol-related ED attendances from 6.8 (range 3-22, median 5.5) in the pre-intervention 6-month period, to 3.7 (range 0-28, median 1.5) in the post-intervention 6-month period (Z = -2.244, p = 0.025). CISS scores showed significant improvement from a pre-intervention median of 13.5 (range 9-16) to a post-intervention median of 6.5 (range 1-10, p = 0.001), corresponding to reduction in alcohol-related problem severity. Conclusion: This pilot study suggests that ACT can be effective in reducing alcohol-related ED attendances and alcohol-related problem severity in patients with AUD who frequently attend ED. A multicenter, prospective study using ACT for such patients across four hospitals in Singapore is currently underway.

Predictive performance of emergency department-specific variables on COVID-19 pneumonia.

Introduction: The majority of patients with COVID-19 infection do not progress to pneumonia. We report emergency department (ED)-specific variables and evaluate their predictive performance on diagnosis of pneumonia, intensive care unit (ICU) admission and death. Methods: This was a retrospective, single-centre cohort study of confirmed COVID-19 patients admitted to a Singapore tertiary hospital. Primary outcome was diagnosis of COVID-19 pneumonia. Secondary outcomes were ICU admission and/or death. Multivariate logistic regression was used to analyse the predictive performance of ED-specific variables. Accuracy of continuous variables was measured by area under receiver operating characteristic (ROC) curve. Results: 294 patients were included. Patients with pneumonia were older (52.0 years, P < 0.001) and had higher C-reactive protein (CRP; 33.8 mg/L, P < 0.001). Patients with indeterminate chest radiograph (CRX) findings were at risk of pneumonia vs. patients with normal CRX (37.5% vs. 4.3%, P < 0.001). Patients admitted to ICU were older (60.0 years, P < 0.001) and had higher CRP (40.0 mg/L, P < 0.001). Diagnosis of COVID-19 pneumonia was associated with ICU admission and death (30.0% vs 0.39%, P < 0.001). Multivariate logistic regression analysis showed that age (aOR 1.07, P = 0.049), CRP (aOR 1.05, P = 0.006) and CRX findings (aOR 50.00, P < 0.001) had increased odds of pneumonia. ROC curve analysis showed that CRP of 23.3 mg/L was the optimal cut-off for predicting pneumonia. Conclusion: Older age, higher CRP and CRX findings are associated with COVID-19 pneumonia, ICU admission and death. Prospective studies should be undertaken to validate these findings.

Early Coronary Angiography Is Associated with Improved 30-Day Outcomes among Patients with Out-of-Hospital Cardiac Arrest.

We evaluated the association between early coronary angiography (CAG) and outcomes in resuscitated out-of-hospital cardiac arrest (OHCA) patients, by linking data from the Singapore Pan-Asian Resuscitation Outcomes Study, with a national registry of cardiac procedures. The 30-day survival and neurological outcome were compared between patients undergoing early CAG (within 1-calender day), versus patients not undergoing early CAG. Inverse probability weighted estimates (IPWE) adjusted for non-randomized CAG. Of 976 resuscitated OHCA patients of cardiac etiology between 2011-2015 (mean(SD) age 64(13) years, 73.7% males), 337 (34.5%) underwent early CAG, of whom, 230 (68.2%) underwent PCI. Those who underwent early CAG were significantly younger (60(12) vs. 66(14) years old), healthier (42% vs. 59% with heart disease; 29% vs. 44% with diabetes), more likely males (86% vs. 67%), and presented with shockable rhythms (69% vs. 36%), compared with those who did not. Early CAG with PCI was associated with better survival and neurological outcome (adjusted odds ratio 1.91 and 1.82 respectively), findings robust to IPWE adjustment. The rates of bleeding and stroke were similar. CAG with PCI within 24 h was associated with improved clinical outcomes after OHCA, without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.

A One-Year Longitudinal Study: Changes in Depression and Anxiety in Frontline Emergency Department Healthcare Workers in the COVID-19 Pandemic.

Frontline healthcare workers (HCWs) fighting COVID-19 have been associated with depression and anxiety, but there is limited data to illustrate these changes over time. We aim to quantify the changes in depression and anxiety amongst Emergency Department (ED) HCWs over one year and examine the factors associated with these changes. In this longitudinal single-centre study in Singapore, all ED HCWs were prospectively recruited face-to-face. Paper-based surveys were administered in June 2020 and June 2021. Depression and anxiety were measured using DASS-21. The results of 241 HCWs who had completed both surveys were matched. There was significant improvement in anxiety amongst all HCWs (Mean: 2020: 2.85 (±3.19) vs. 2021: 2.54 (±3.11); Median: 2020: 2 (0-4) vs. 2021: 2 (0-4), p = 0.045). HCWs living with elderly and with concerns about infection risk had higher odds of anxiety; those living with young children had lower odds of anxiety. There was significant worsening depression amongst doctors (Mean: 2020: 2.71 (±4.18) vs. 2021: 3.60 (±4.50); Median: 2020: 1 (0-3) vs. 2021: 3 (0-5), p = 0.018). HCWs ≥ 41 years, living with elderly and with greater concerns about workload had higher odds of depression. HCWs who perceived better workplace support and better social connectedness had lower odds of depression. In summary, our study showed significant improvement in anxiety amongst ED HCWs and significant worsening depression amongst ED doctors over one year. Age, living with elderly, and concerns about workload and infection risk were associated with higher odds of depression and anxiety.