Emergency Department Syndromic Surveillance Research Articles

Using an Emergency Department Syndromic Surveillance System to Assess the Impact of Cyclone Bejisa, Reunion Island

On January 2, 2014 the cyclone Bejisa struck Reunion Island. In anticipation, an epidemiological surveillance was set up in order to assess the impact in the aftermath of the cyclone. Short-term health effects were assessed using a syndromic surveillance system based on data of EDs and EMS. A peak of calls to the EMS was observed the day of the cyclone and an increase of ED visits over the next two days. At the same time, a significant increase of visits for trauma, burns, conjunctivitis was detected. The reactivity and the flexibility of the syndromic surveillance system allowed to rapidly assess the health impact of the cyclone.

Syndromic Surveillance of Motor Vehicle Crash Related Injuries in Nebraska

Traffic crashes cost Nebraska $1.6 billion a year, are the leading cause of injury death, and the fourth leading cause of injury hospital treatment in Nebraska. This pilot study demonstrates the value of emergency department syndromic surveillance data to aid the surveillance of motor vehicle crash (MVC) related injuries in Nebraska. Results of this study suggests that emergency department syndromic surveillance data can be used for the timely identification of MVC-related injuries in Nebraska. This will allow stakeholders to identify accident hot spots and better deployments of accident prevention assets and procedures.

How Should We Be Conducting Routine Analysis of Traditional Emergency Department Syndromic Surveillance Data?

This roundtable will focus on how traditional emergency department syndromic surveillance systems should be used to conduct daily or periodic disease surveillance. As outbreak detection using these systems has demonstrated an equivocal track record, epidemiologists have sought out other interesting uses for these systems. Over the numerous years of the International Society for Disease Surveillance (ISDS) Conference, many of these studies have been presented; however, there has been a dearth of discussion related to how these systems should be used. This roundtable offers a forum to discuss best practices for the routine use of emergency department syndromic surveillance data.

Using an Emergency Department Syndromic Surveillance System to investigate the impact of extreme cold weather events

This report describes the development of novel syndromic cold weather public health surveillance indicators for use in monitoring the impact of extreme cold weather on attendances at EDs, using data from the 2010–11 and 2011–12 winters.A number of new surveillance indicators were created specifically for the identification and monitoring of cold weather related ED attendances, using the diagnosis codes provided for each attendance in the Emergency Department Syndromic Surveillance System (EDSSS), the first national syndromic surveillance system of its kind in the UK. Using daily weather data for the local area, a time series analysis to test the sensitivity of each indicator to cold weather was undertaken.Diagnosis codes relating to a health outcome with a potential direct link to cold weather were identified and assigned to a number of ‘cold weather surveillance indicators’. The time series analyses indicated strong correlations between low temperatures and cold indicators in nearly every case. The strongest fit with temperature was cold related fractures in females, and that of snowfall was cold related fractures in both sexes.Though currently limited to a small number of sentinel EDs, the EDSSS has the ability to give near real-time detail on the magnitude of the impact of weather events. EDSSS cold weather surveillance fits well with the aims of the Cold Weather Plan for England, providing information on those particularly vulnerable to cold related health outcomes severe enough to require emergency care. This timely information aids those responding to and managing the effects on human health, both within the EDs themselves and in the community as a whole.

Near Real-Time Monitoring of Emergency Department Syndromic Surveillance Data During the 2013 Super Bowl and Mardi Gras Events in New Orleans, LA

The Louisiana Office of Public Health (OPH) conducts emergency department (ED) syndromic surveillance using Louisiana Early Event Detection System (LEEDS). LEEDS automatically processes electronic chief complaint and diagnosis data to identify ED visits indicative of specific syndromes. OPH monitored LEEDS for infectious disease and injury syndromes during the 2013 Super Bowl and Mardi Gras activities in New Orleans. C2 and CPA were used to detect syndrome aberrations. This surveillance provided essential situational awareness necessary to indicate if and when the utilization of public health resources may have been needed to prevent additional injury and illness.

Description of a School Nurse Visit Syndromic Surveillance System and Comparison to Emergency Department Visits, New York City

We compared school nurse visit syndromic surveillance system data to emergency department (ED) visit data for monitoring illness in New York City schoolchildren. School nurse visit data recorded in an electronic health record system are used to conduct daily surveillance of influenza-like illness, fever-flu, allergy, asthma, diarrhea, and vomiting syndromes. We calculated correlation coefficients to compare the percentage of syndrome visits to the school nurse and ED for children aged 5 to 14 years, from September 2006 to June 2011. Trends in influenza-like illness correlated significantly (correlation coefficient = 0.89; P < .001) and 72% of school signals occurred on days that ED signaled. Trends in allergy (correlation coefficient = 0.73; P < .001) and asthma (correlation coefficient = 0.56; P < .001) also correlated and school signals overlapped with ED signals on 95% and 51% of days, respectively. Substantial daily variation in diarrhea and vomiting visits limited our ability to make comparisons. Compared with ED syndromic surveillance, the school nurse system identified similar trends in influenza-like illness, allergy, and asthma syndromes. Public health practitioners without school-based surveillance may be able to use age-specific analyses of ED syndromic surveillance data to monitor illness in schoolchildren.

The impact of thunderstorm asthma on emergency department attendances across London during July 2013

BackgroundThis study illustrates the potential of using emergency department attendance data, routinely accessed as part of a national syndromic surveillance system, to monitor the impact of thunderstorm asthma.MethodsThe Emergency Department...

Influenza assessment centres: a case study of pandemic preparedness to alleviate excess emergency department volume

Influenza assessment centres (IACs) were deployed to reduce emergency department (ED) volumes during the pH1N1 influenza outbreak in the Kingston, Frontenac, Lennox and Addington (KFL&A) public health region of Ontario, Canada, in the fall of 2009. We present a case study for the deployment of IACs to reduce ED visit volume during both periods of pandemic and seasonal communicable disease outbreak. An emergency department syndromic surveillance system was used to trigger the deployment of eight geographically distributed IACs and to time their staggered closure 3 weeks later. We compared actual and expected ED visit volumes in the KFL&A region to neighbouring regions where no IACs operated by time series regression analysis before, during, and after IAC operation. The deployment of IACs was triggered with a rise in overall ED volume at the hospitals in the KFL&A region to a level 10% above the 6-month running average. The IACs assessed 2,284 patients during 3 weeks of operation. Thirty-three patients were admitted directly to the hospital from the IACs, bypassing the EDs. During the operation of the IACs, the hospitals in the KFL&A region experienced a modest decrease in daily visits when compared to the 3 previous weeks. Overall ED visit volume in the hospitals in the neighbouring regions increased 105% during the period of IAC operation. Operating stand-alone influenza IACs may reduce ED volumes during periods of increased demand, as observed during an anticipated pandemic situation.

Adaptation of GUARDIAN for Syndromic Surveillance During the NATO Summit

During the NATO summit, the local health department was charged with collecting and analyzing syndromic surveillance data from emergency department (ED) visits that may indicate a man-made or naturally occurring infectious disease threat. GUARDIAN, an automated surveillance system, was programmed to conduct ED syndromic surveillance during the NATO summit. The automated GUARDIAN surveillance reports not only provided timely counts of potentially positive cases for each syndrome but also provided trend analysis with baseline measures.

When it Rains it Pours: Real-time Situational Awareness for Two Weather Emergencies in Connecticut

During 2011 Connecticut was impacted by two major weather events. The Hospital Emergency Department Syndromic Surveillance System (HEDSS) was utilized to provide real-time situational awareness during the response and recovery phases of both storm events. Increased emergency department utilization for carbon monoxide exposure, asthma, and hypothermia were observed. HEDSS data were likely an underestimation of true disease/injury in the community following the storm events. HEDSS should continue to be used, in conjunction with other existing surveillance systems, for near real-time situational monitoring during public health emergencies.

Using Change Point Detection for Monitoring the Quality of Aggregate Data

Introduction: Data consisting of counts or indicators aggregated from multiple sources pose particular problems for data quality monitoring when the users of the aggregate data are blind to the individual sources. This arises when agencies wish to share data but for privacy or contractual reasons are only able to share data at an aggregate level. If the aggregators of the data are unable to guarantee the quality of either the sources of the data or the aggregation process then the quality of the aggregate data may be compromised. This situation arose in the Distribute surveillance system (1). Distribute was a national emergency department syndromic surveillance project developed by the International Society for Disease Surveillance for influenza-like-illness (ILI) that integrated data from existing state and local public health department surveillance systems, and operated from 2006 until mid 2012. Distribute was designed to work solely with aggregated data, with sites providing data aggregated from sources within their jurisdiction, and for which detailed information on the un-aggregated ‘raw’ data was unavailable. Previous work (2) on Distribute data quality identified several issues caused in part by the nature of the system: transient problems due to inconsistent uploads, problems associated with transient or long-term changes in the source make up of the reporting sites and lack of data timeliness due to individual site data accruing over time rather than in batch. Data timeliness was addressed using prediction intervals to assess the reliability of the partially accrued data (3). The types of data quality issues present in the Distribute data are likely to appear to some extent in any aggregate data surveillance system where direct control over the quality of the source data is not possible. In this work we present methods for detecting both transient and long-term changes in the source data makeup.

Analysis of Heat Illness using Michigan Emergency Department Syndromic Surveillance

During a severe heat wave in Michigan in 2012, heat-related Emergency Department cases were identified using the Michigan Emergency Department (ED) Syndromic Surveillance System. Heat-related ED visits were analyzed by patient age, gender, and chief complaint. These ad hoc enhanced analyses were performed by Michigan Department of Community Health epidemiologists and provided to public health partners for situational awareness and to guide their responses to the heat event. Significant differences in the patterns of heat-related illnesses were observed during the heat-wave period compared to a reference period.

Evaluating Syndromic Data for Surveillance of Non-infectious Disease

Syndromic surveillance (SS) data has predominantly been used for surveillance of infectious disease and for broad symptom types that could be associated with bioterrorism. This work evaluates several non-infectious disease related syndromes, such as asthma, oral health and hypothermia, by comparing daily syndrome counts and annual hospital syndrome counts based on emergency department (ED) SS data vs. New York Statewide Planning and Research Cooperative System (SPARCS) data. SPARCS data are based on clinical diagnoses providing a means for evaluating how well non-infectious disease trends are captured by ED SS chief complaint data.

Surveillance and Vaccine Effectiveness of an Influenza Epidemic Predominated by Vaccine-Mismatched Influenza B/Yamagata-Lineage Viruses in Taiwan, 2011−12 Season

IntroductionThe 2011−12 trivalent influenza vaccine contains a strain of influenza B/Victoria-lineage viruses. Despite free provision of influenza vaccine among target populations, an epidemic predominated by influenza B/Yamagata-lineage viruses occurred during the 2011−12 season in Taiwan. We characterized this vaccine-mismatched epidemic and estimated influenza vaccine effectiveness (VE).MethodsInfluenza activity was monitored through sentinel viral surveillance, emergency department (ED) and outpatient influenza-like illness (ILI) syndromic surveillance, and case-based surveillance of influenza with complications and deaths. VE against laboratory-confirmed influenza was evaluated through a case-control study on ILI patients enrolled into sentinel viral surveillance. Logistic regression was used to estimate VE adjusted for confounding factors.ResultsDuring July 2011−June 2012, influenza B accounted for 2,382 (72.5%) of 3,285 influenza-positive respiratory specimens. Of 329 influenza B viral isolates with antigen characterization, 287 (87.2%) were B/Yamagata-lineage viruses. Proportions of ED and outpatient visits being ILI-related increased from November 2011 to January 2012. Of 1,704 confirmed cases of influenza with complications, including 154 (9.0%) deaths, influenza B accounted for 1,034 (60.7%) of the confirmed cases and 103 (66.9%) of the deaths. Reporting rates of confirmed influenza with complications and deaths were 73.5 and 6.6 per 1,000,000, respectively, highest among those aged ≥65 years, 50−64 years, 3−6 years, and 0−2 years. Adjusted VE was −31% (95% CI: −80, 4) against all influenza, 54% (95% CI: 3, 78) against influenza A, and −66% (95% CI: −132, −18) against influenza B.ConclusionsThis influenza epidemic in Taiwan was predominated by B/Yamagata-lineage viruses unprotected by the 2011−12 trivalent vaccine. The morbidity and mortality of this vaccine-mismatched epidemic warrants careful consideration of introducing a quadrivalent influenza vaccine that includes strains of both B lineages.

Emergency Department Surveillance as a Proxy For The Prediction of Circulating Respiratory Viral Disease in Eastern Ontario

Seasonal outbreaks of winter respiratory viruses are responsible for increases in morbidity and mortality in the community. Previous studies have used hospitalizations, intensive care unit and emergency department (ED) visits as indicators of seasonal influenza incidence. To evaluate whether ED visits can be used as a proxy to detect respiratory viral disease outbreaks, as measured by laboratory confirmation. An Emergency Department Syndromic Surveillance system was used to collect ED chief complaints in Eastern Ontario from 2006 to 2010. Comparable laboratory-confirmed cases of respiratory viral infections were collected from the Public Health Ontario Laboratory in Kingston, Ontario. Correlations between ED visits and laboratory-confirmed cases were calculated. Laboratory-confirmed cases of selected respiratory viruses were significantly correlated with ED visits for respiratory and fever/influenza-like illness. In particular, respiratory syncytial virus (Spearman's rho = 0.593), rhinovirus (Spearman's rho = 0.280), influenza A (Spearman's rho = 0.528), influenza B (Spearman's rho = 0.426) and pH1N1 (Spearman's rho = 0.470) increased laboratory test levels were correlated with increased volume of ED visits across a number of age demographics. For the entire study population and all studied viruses, the Spearman's rho was 0.702, suggesting a strong correlation with ED visits. Laboratory-confirmed cases lagged in reporting by between one and two weeks for influenza A and pH1N1 compared with ED visit volume. These findings support the use of an Emergency Department Syndromic Surveillance system to track the incidence of respiratory viral disease in the community. These methods are efficient and can be performed using automated electronic data entry versus the inherent delays in the primary care sentinel surveillance system, and can aid the timely implementation of preventive and preparatory health interventions.

Developing a new syndromic surveillance system for the London 2012 Olympic and Paralympic Games.

Syndromic surveillance is vital for monitoring public health during mass gatherings. The London 2012 Olympic and Paralympic Games represents a major challenge to health protection services and community surveillance. In response to this challenge the Health Protection Agency has developed a new syndromic surveillance system that monitors daily general practitioner out-of-hours and unscheduled care attendances. This new national system will fill a gap identified in the existing general practice-based syndromic surveillance systems by providing surveillance capability of general practice activity during evenings/nights, over weekends and public holidays. The system will complement and supplement the existing tele-health phone line, general practitioner and emergency department syndromic surveillance systems. This new national system will contribute to improving public health reassurance, especially to meet the challenges of the London 2012 Olympic and Paralympic Games.

Establishing an emergency department syndromic surveillance system to support the London 2012 Olympic and Paralympic Games

BackgroundThe London 2012 Olympic and Paralympic Games is a mass gathering event that will present a major public health challenge. The Health Protection Agency, in collaboration with the College of...

Evaluating the New York City Emergency Department Syndromic Surveillance for Monitoring Influenza Activity during the 2009-10 Influenza Season

Objective: To use laboratory data to assess the specificity of syndromes used by the New York City emergency department (ED) syndromic surveillance system to monitor influenza activity. Design: For the period from October 1, 2009 through March 31, 2010, we examined the correlation between citywide ED syndrome assignment and laboratory-confirmed influenza and respiratory syncytial virus (RSV). In addition, ED syndromic data from five select NYC hospitals were matched at the patient and visit level to corresponding laboratory reports of influenza and RSV. The matched dataset was used to evaluate syndrome assignment by disease and to calculate the sensitivity and specificity of the influenza-like illness (ILI) syndrome. Results: Citywide ED visits for ILI correlated well with influenza laboratory diagnoses (R=0.92). From October 1, 2009, through March 31, 2010, there were 264,532 ED visits at the five select hospitals, from which the NYC Department of Health and Mental Hygiene (DOHMH) received confirmatory laboratory reports of 655 unique cases of influenza and 1348 cases of RSV. The ED visit of most (56%) influenza cases had been categorized in the fever/flu syndrome; only 15% were labeled ILI. Compared to other influenza-related syndromes, ILI had the lowest sensitivity (15%) but the highest specificity (90%) for laboratory-confirmed influenza. Sensitivity and specificity varied by age group and influenza activity level. Conclusions: The ILI syndrome in the NYC ED syndromic surveillance system served as a specific but not sensitive indicator for influenza during the 2009-2010 influenza season. Despite its limited sensitivity, the ILI syndrome can be more informative for tracking influenza trends than the fever/flu or respiratory syndromes because it is less likely to capture cases of other respiratory viruses. However, ED ILI among specific age groups should be interpreted alongside laboratory surveillance data. ILI remains a valuable tool for monitoring influenza activity and trends as it facilitates comparisons nationally and across jurisdictions and is easily communicated to the public.

Evaluation of the Connecticut hospital emergency department syndromic surveillance system for monitoring of community gastrointestinal illness

Evaluation of the Connecticut hospital emergency department syndromic surveillance system for monitoring of community gastrointestinal illness

Syndromic Surveillance during Pandemic (H1N1) 2009 Outbreak, New York, New York

We compared emergency department and ambulatory care syndromic surveillance systems during the pandemic (H1N1) 2009 outbreak in New York City. Emergency departments likely experienced increases in influenza-like-illness significantly earlier than ambulatory care facilities because more patients sought care at emergency departments, differences in case definitions existed, or a combination thereof.