First estimates of the impact of 2010, 2011 and 2012 heat waves on mortality in metropolitan France

Methods to analyse the health impacts of heat waves; real-time follow up and a posteriori estimations Since 2004, France has implemented a National Heat wave Plan in order to prevent health consequences of a heat wave. In this system, the French Institute for Public Health Surveillance is responsible for alert proposal and for the surveillance of the health impacts. Alert proposals are based on the meteorological forecasts provided by the National Weather Service (Météo-France), according to rules defined by the alert system for heat waves. It can be useful to have a description of the health situation in the affected departments, in order to help decision. This is particularly important to define the level of appropriate measures, or to decide the end of an alert. Based on our experience since 2004 and on a literature review, we defined a new list of health indicators to monitor during heat waves. We focused on mortality, emergency visits and reasons for emergency calls. These indicators are collected during summer in each metropolitan department. We proposed two statistical methods to help interpreting these indicators: one based on control charts, and the historical limits method. We also proposed a method to quickly estimate the impact on mortality after a heat wave. This indicator will enable to compare the impact of heat waves along time, and to make hypotheses to orientate more detailed studies. These works will enable to improve the efficiency of the heat warning system, which must be responsive and robust, in a context of increasing vulnerability to heat waves.