Purpose. To determine whether out-of-hospital cardiac arrest (OHCA) incidence was homogeneously distributed at municipality level in Swiss Canton Ticino, a large territory including rural and urban areas; to assess areas of increased risk of OHCAs over time, according to demographic characteristics of the resident population and to predict OHCA events at municipality level. Methods. All data regarding OHCAs which occurred in Canton Ticino (Switzerland) from January 1, 2005, through to December 31, 2017 were entered into a registry and geolocated. Demographic characteristics (sex composition and age distribution) at the level of single municipality were collected from the Federal Office of Statistics. Counting and incidences were calculated at level of each municipality, by taking into account gender and age distribution.  The Integrated Nested Laplace Approximation (INLA) was used for estimate OHCA incidences with related uncertainty in a training sample (OHCAs occurred between 2005 and 2015), and to predict OHCA incidences in a validation cohort (OHCAs occurred in 2016-2017). 
 Results. A total of 2129 OHCAs occurred in the 117 municipalities of Canton Ticino. We observed a concentration of cardiac events in the Southern part of Ticino, with a spatial distribution that followed the geographical configuration of valleys. As expected, the absolute numbers of OHCAs were higher in more populated areas, but some less populated municipalities showed relevant OHCAs incidence, that could be explained with a higher prevalence of male people with an age ≥ 80 years old. When tested in the validation cohort (years 2016-2017), the predictive model was able to capture roughly 90% of OHCAs variability. 
 Conclusions. Significant differences in OHCA incidence among municipalities. A predictive model taking into account territorial gender and age distribution is able to predict up to 90% of events variability.  This approach provides a great opportunity for preventive measures and reduction in access time to OHCA.

8 - Spatial-temporal heterogeneity of out-of-hospital cardiac arrest incidence in Swiss Canton Ticino