Socioeconomic Disadvantage Is Associated with a Higher Incidence of Aneurysmal Subarachnoid Hemorrhage

Background and Purpose: Aneurysmal subarachnoid hemorrhage (aSAH) incidenceis not well studied. Varied definitions of “subarachnoid hemorrhage” haveled to a lack of clarity regarding aSAH incidence. The impact of area-level socioeconomicdisadvantage and geographical location on the incidence of aSAHalso remains unclear. Using a population-based statewide study, we examined theincidence of aSAH in relation to socioeconomic disadvantage and geographicallocation. Methods: A retrospective cohort study of nontraumatic subarachnoid hemorrhagesfrom 2010 to 2014 was undertaken. Researchers manually collected datafrom multiple overlapping sources including statewide administrative databases,individual digital medical records, and death registers. Age-standardized rates (ASRs)per 100,000 person years were calculated using the 2001 Australian population.Differences in incidence rate ratios were calculated by age, sex, area-level socioeconomicstatus, and geographical location using Poisson regression. Results: Thecohort of 237 cases (mean age, 61.0 years) with a female predominance of 166(70.04%) included 159 confirmed aSAH, 52 community-based deaths, and 26 probablecases. The ASR for aSAH was 9.99 (95% confidence interval [CI], 8.69-11.29).A significant association between area-level socioeconomic disadvantage and incidencewas observed, with the rate of aSAH in disadvantaged geographical areasbeing 1.40 times higher than that in advantaged areas (95% CI, 1.11-1.82; P = .012).Conclusion: This study uses a comprehensive search of multiple datasources to define a new baseline of aSAH within an Australian population. Thisstudy presents a higher incidence rate of aSAH with socioeconomic variations.As a key risk factor that may explain this paradox, addressing socioeconomic inequalitiesis important for effective prevention and management interventions