Lower socio-economic status is associated with first-ever stroke incidence: An Australian state-wide record linkage...

Although socio-economic status (SES) is a recognised risk factor for stroke, few studies have examined stroke incidence by SES in Australia. We investigated the incidence of first-ever stroke by SES using state-wide record linkage data.

This retrospective cohort study used linked Tasmanian Admitted Patient Care and the Death Registry data. Fatal and non-fatal strokes 2007-2020 were identified using ICD-10 codes (8-year clearance period) to identify first-ever strokes 2015-2020. SES was from Index of Relative Socio-economic Advantage and Disadvantage by quintiles (low, low medium, medium, medium high, high). Covariates included sex, age, and remoteness. Population denominators (2016 Australian population) were used to calculate crude and age-standardised incidence rates. Poisson regression models estimated adjusted incidence rate ratios (IRR) for first-ever stroke by SES group.

We identified 4901 first-ever stroke cases (63% ischaemic stroke, mean [SD] age 75 [14] years, 52% female). Ischaemic heart disease (12% lowest vs 7% highest SES), diabetes (26% lowest vs 18% highest SES), and hypertension (48% lowest vs 39% highest SES) were significantly different by SES. The age-standardised rate was 134/100,000 persons (95% CI 130, 138). Compared to the high SES group, the IRR for first-ever stroke was 1.20 (95% CI 1.09, 1.33) for the low medium SES group and 1.33 (95% CI 1.22, 1.46) for the low SES group, adjusting for age, sex, stroke incident year, and remoteness.

Lower SES groups had a higher incidence of first-ever stroke. Public health and primary care strategies targeting stroke risk factors in these groups may reduce stroke incidence.