Syndromic Surveillance Based on Emergency Visits: A Reactive Tool for Unusual Events Detection

OBJECTIVE: To show with examples that syndromic surveillance system can be a reactive tool for public health surveillance. INTRODUCTION: The late health events such as the heat wave of 2003 showed the need to make public health surveillance evolve in France. Thus, the French Institute for Public Health Surveillance has developed syndromic surveillance systems based on several information sources such as emergency departments (1). In Reunion Island, the chikungunya outbreak of 2005–2006, then the influenza pandemic of 2009 contributed to the implementation and the development of this surveillance system (2–3). In the past years, this tool allowed to follow and measure the impact of seasonal epidemics. Nevertheless, its usefulness for the detection of minor unusual events had yet to be demonstrated. METHODS: - Qualitative indicators for the alert (every visit whose diagnostic relates to a notifiable disease or potential epidemic disease); - Quantitative indicators for the epidemic/cluster detection (number of visits based on syndromic grouping). Daily and weekly analyses are carried out. A decision algorithm allows to validate the signal and to organize an epidemiological investigation if necessary. RESULTS: Each year, about 150 000 visits are registered in the six emergency departments that is 415 consultations per day on average. Several unusual health events on small-scale were detected early. In August 2011, the surveillance system allowed to detect the first autochthonous cases of measles, a few days before this notifiable disease was reported to health authorities (Figure 1). In January 2012, the data of emergency departments allowed to validate the signal of viral meningitis as well as to detect a cluster in the West of the island and to follow its trend. In June 2012, a family foodborne illness was detected from a spatio-temporal cluster for abdominal pain by the surveillance system and was confirmed by epidemiological investigation (Figure 2). CONCLUSIONS: Despite the improvement of exchanges with health practitioners and the development of specific surveillance systems, health surveillance remains fragile for the detection of clusters or unusual health events on small scale. The syndromic surveillance system based on emergency visits has proved to be relevant for the identification of signals leading to health alerts and requiring immediate control measures. In the future, it will be necessary to develop these systems (private practitioners, sentinel schools) in order to have several indicators depending on the degree of severity

Usefulness of Syndromic Surveillance during Ultra-endurance Running Races: Example with the “Grand Raid de la Réunion” Ultra Trail

The "Grand Raid de la Réunion" is one of the hardest ultra trails in the world. This endurance running race has consequences on health's runners. We used syndromic surveillance to estimate the health impact of this sporting event on the Emergency Departments (ED) of Reunion Island. During the race's period, a global increase of the ED visits all causes was observed. The syndromic surveillance system detected a significant ED visits' increase for hydro-electrolytic disorders. These results highlight the usefulness of syndromic surveillance to estimate the impact on health of a mass gathering on a sporting event of great magnitude

Using a Syndromic Approach to Study Health Impact and Risk Factors of Alcohol Intoxication in Reunion Island

In Reunion Island, alcohol is a major public health problem. Syndromic surveillance system based on ED data was used for describe alcohol intoxication visits between 2010-2012 and factors associated with their variations. During the study period, alcohol intoxication was the second leading cause of all visits in ED. Time-series models showed a robust association between ED visits and days of minimum social benefits payment, weekends, public holidays. These results will be transmitted to health authorities in order to orient the public health policies

Using a Syndromic Approach to Study Health Impact and Risk Factors of Alcohol Intoxication in Reunion Island

In Reunion Island, alcohol is a major public health problem. Syndromic surveillance system based on ED data was used for describe alcohol intoxication visits between 2010-2012 and factors associated with their variations. During the study period, alcohol intoxication was the second leading cause of all visits in ED. Time-series models showed a robust association between ED visits and days of minimum social benefits payment, weekends, public holidays. These results will be transmitted to health authorities in order to orient the public health policies

Usefulness of Syndromic Surveillance during Ultra-endurance Running Races: Example with the “Grand Raid de la Réunion” Ultra Trail

The "Grand Raid de la Réunion" is one of the hardest ultra trails in the world. This endurance running race has consequences on health's runners. We used syndromic surveillance to estimate the health impact of this sporting event on the Emergency Departments (ED) of Reunion Island. During the race's period, a global increase of the ED visits all causes was observed. The syndromic surveillance system detected a significant ED visits' increase for hydro-electrolytic disorders. These results highlight the usefulness of syndromic surveillance to estimate the impact on health of a mass gathering on a sporting event of great magnitude

Predicting acute coronary syndrome in males and females with chest pain who call an emergency medical communication centre

International audienceBackground Chest pain is a frequent reason for calls in emergency medical communication centre (EMCC). Detecting a coronary origin by phone is a challenge. This is especially so as the presentations differ according to gender. We aimed to establish and validate a sex-based model to predict a coronary origin of chest pain in patients calling an EMCC. Methods This prospective cohort study enrolled patients at 18 years of age or older who called the EMCC because of non-traumatic chest pain. The main outcome was the diagnosis of acute coronary syndrome (ACS) determined by expert evaluation of patient files. Results During 18 months, 3727 patients were enrolled: 2097 (56%) men and 1630 (44%) women. ACS was diagnosed in 508 (24%) men and 139 (9%) women. For men, independent factors associated with an ACS diagnosis were age, tobacco use, severe and permanent pain; retrosternal, breathing non-related and radiating pain; and additional symptoms. The area under the receiver operating characteristic curve (AUC) was 0.76 (95% confidence interval [CI] 0.73–0.79) for predicting ACS. The accuracy of the male model to predict ACS was validated in a validation dataset (Hosmer-Lemeshow test: p = 0.554); the AUC was 0.77 (95%CI 0.73–0.80). For women, independent factors associated with an ACS diagnosis were age ≥ 60 years, personal history of coronary artery disease, and breathing non-related and radiating pain. The AUC was 0.79 (95%CI 0.75–0.83). The accuracy of the female model to predict ACS was not validated in the validation dataset (Hosmer-Lemeshow test: p = 0.035); the AUC was 0.67 (95%CI 0.60–0.74). Conclusions Predictors of an ACS diagnosis in patients calling an EMCC for chest pain differ between men and women. We developed an accurate predictive model for men, but for women, the accuracy was poor. Trial registration This study is registered with ClinicalTrials.gov ( NCT02042209 )