Are ethnic inequalities in 30-day ischaemic stroke survival emerging as treatment becomes more effective?

Abstract

Studies of ethnic differences in stroke survival have produced inconsistent findings. As treatment becomes more effective, inequalities may increase. We examine time trends in ischaemic stroke case fatality in New Zealand.The 30-day case fatality rate (CFR) of ischaemic stroke in New Zealand was calculated from routinely collected data for two 5-year periods (2000-2004 and 2010-2014) in Māori, Pacific, Asian and European people. A Poisson regression model tested ethnic inequalities between Europeans and people of other ethnicities in each time period.From 2000-2004 to 2010-2014, the age-sex standardised CFR in Europeans fell from 13.4% (95% CI 13.0 to 13.9%) to 10.7% (10.3 to 11.1%). In Pacific and Asian people, the CFR rose between the two periods, and in Māori there was a drop from 18.2% to 16.2%; neither of these differences were statistically significant. After controlling for socio-demographic variables, service factors and comorbidities, the CFR was higher for Māori than Europeans in 2000-2004, and for all ethnic groups compared with Europeans in 2010-2014. CFR ethnic inequality rose over that time-the change being statistically significant for Pacific (p=0.033) and Asian (p=0.010), and of borderline significance for Māori (p=0.053).Ethnic inequalities in 30-day ischaemic stroke survival have increased significantly in the last 10 years. This may be due to differences in severity at presentation, or in access and utilisation of the increasingly effective acute and hyper-acute stroke interventions.