Abstract P154: Disparities in Geographic and Temporal Trends of Myocardial Infarction Hospitalizations in Florida, 2005-2014

Background: Knowledge of the extent of geographic disparities in the burden of myocardial infarction (MI) is useful for allocation of scarce public health resources to reduce health disparities and improve population health, regardless of whether MI is the primary or secondary cause for hospitalization. The objectives of this study were to identify: (a) geographic disparities in hospitalization risks for MI in Florida; and (b) the temporal changes in these disparities from 2005 to 2014. Methodology: We aggregated county-level data for principal and secondary inpatient MI-related hospital discharges in Florida between 2005 and 2014 by 2-year intervals and calculated age- and sex- adjusted MI hospitalization risks for each time interval. We identified spatial clusters of low- and high-risk MI hospitalization risks using circular spatial scan statistics and tracked MI risks in clusters that persisted throughout the 10-year study period. We also assessed health disparities between persistent high- and low-risk clusters at the end of the study (2013-2014) compared to the beginning of the study (2005-2006) periods. Results: MI hospitalization risks decreased by 15% in Florida overall during the 10-year study period. However, we found persistent disparities in MI risks by geographic location, with high-risk clusters occurring in north-, west-, south-central and southeast Florida, and low-risk clusters occurring in southeast and southwest Florida. A low-risk cluster that transitioned to high-risk status in the last four years of study was identified in northwest Florida. We also found substantial differences in the magnitude of decline in MI risks amongst clusters, with risks decreasing by 5%, 16% and 31% in high-risk clusters in west central, south central and north central Florida, respectively, and by 6.5% and 26% in low-risk clusters in southwest and southeast Florida, respectively. Furthermore, the risks only decreased during the first 6-8 years of study, after which they leveled off or ticked upwards. Consequently, health disparities between high- and low-risk clusters at the end of the study compared to the beginning of the study period decreased by 57% and 31.5% in north- and south-central Florida, respectively, but they remained relatively unchanged in west central Florida. Moreover, MI hospitalization risks in high-risk clusters lag behind those in low-risk clusters by at least a decade. Conclusion: Myocardial infarction hospitalization risks declined modestly during 10-year study period. However, persistent disparities continue to exist across space and time. Addressing these disparities will require targeting intervention efforts to counties with persistently high risks.