High risk neighbourhoods: The effect of neighbourhood level factors on cardiac arrest incidence.

BACKGROUND: Numerous studies have shown significant neighbourhood level variation in out-of-hospital cardiac arrest (OHCA) incidence rates, however, few have provided an explanation for these disparities beyond traditional socioeconomic measures. METHODS: This was a retrospective study using data from a large population-based OHCA database (Rescu Epistry). We included adults ≥20 years who experienced a non-traumatic OHCA and were treated by emergency medical services within Toronto, Canada between 2006-2012. The residential address of each OHCA patient was spatially mapped to 1 of 517 Toronto census tracts (CTs). Patient and CT level characteristics were included in multivariate regression models to assess their association with OHCA incidence per 100,000 persons. RESULTS: Of the 7775 OHCAs occurring in the study area, 7692 (98.9%) were eligible for inclusion. OHCA incidence rates varied widely across CT quintiles, with rates differing almost 4-fold (109.1 per 100,000 yearly Q5 most deprived vs. 30.0 per 100,000 yearly Q1 least deprived p < 0.0001). Numerous areas of high incidence adjacent to areas of low incidence were observed. After adjustment, all variables except the Activity Friendly Index showed highly significant linear trends, with increasing age, sex ratio, diabetes prevalence, material deprivation and ethnic concentration being independently associated with increasing OHCA incidence. In contrast, we did not observe a linear relationship between high OHCA incidence and median household income. CONCLUSIONS: This study showed almost 4-fold OHCA incidence variability across a large metropolitan area. This variability was partially correlated with population and health data, but not typical socioeconomic predictors, such as median household income.

Patient and hospital factors predict use of coronary angiography in out-of-hospital cardiac arrest patients.

AIM: To describe the association between patient- and hospital-level factors and coronary angiography among patients who suffer out-of-hospital cardiac arrest (OHCA). METHODS: A population-based retrospective cohort study using data from 28 hospitals in Southern Ontario between March 1, 2010 and December 31, 2014. We included consecutive adult patients with atraumatic, OHCA, who achieved return of spontaneous circulation, and were alive at least six hours after hospital arrival. Multilevel logistic regression was used to measure the relationship between patient- and hospital-level covariates and receipt of coronary angiography. RESULTS: Among 2578 consecutive patients, the mean age was 67(±15), 69% were male, 49% had a shockable initial cardiac arrest rhythm and 84% were comatose at hospital admission. Overall, 33% of the study population received coronary angiography. This varied markedly by hospital of first assessment (13%-70%). Factors associated with receiving coronary angiography included ST-segment elevation (OR = 21.30, CI95 16.17-28.04), a shockable initial cardiac rhythm (OR = 5.00, CI95 3.70-6.75), bystander AED use (OR = 2.51, CI95 1.49-4.23), EMS-witnessed arrest (OR = 2.49, CI95 1.62-3.81), initial admission to a PCI center (OR = 2.94, CI95 1.66-5.21), age (OR = 1.04, CI95 1.02-1.07 for age <55, OR = 0.91, CI95 0.88-0.94 for age ≥55), and pre-hospital ROSC (OR = 1.59, CI95 1.06-2.39). CONCLUSION: We identified patient- and hospital-level factors that explain some of the variability in the use of coronary angiography for OHCA. Future work should determine which post arrest patients will benefit most from urgent coronary angiography and evaluate knowledge translation strategies to ensure consistent delivery of best practices.