Ethnic differences in stroke outcomes in Aotearoa New Zealand: A national linkage study

Background: Ethnic differences in post-stroke outcomes have been largely attributed to biological and socioeconomic characteristics resulting in differential risk factor profiles and stroke subtypes, but evidence is mixed. Aims: This study assessed ethnic differences in stroke outcome and service access in New Zealand (NZ) and explored underlying causes in addition to traditional risk factors. Methods: This national cohort study used routinely collected health and social data to compare post-stroke outcomes between NZ Europeans, Māori, Pacific Peoples, and Asians, adjusting for differences in baseline characteristics, socioeconomic deprivation, and stroke characteristics. First and principal stroke public hospital admissions during November 2017 to October 2018 were included (N = 6879). Post-stroke unfavorable outcome was defined as being dead, changing residence, or becoming unemployed. Results: In total, 5394 NZ Europeans, 762 Māori, 369 Pacific Peoples, and 354 Asians experienced a stroke during the study period. Median age was 65 years for Māori and Pacific Peoples, and 71 and 79 years for Asians and NZ Europeans, respectively. Compared with NZ Europeans, Māori were more likely to have an unfavorable outcome at all three time-points (odds ratio (OR) = 1.6 (95% confidence interval (CI) = 1.3–1.9); 1.4 (1.2–1.7); 1.4 (1.2–1.7), respectively). Māori had increased odds of death at all time-points (1.7 (1.3–2.1); 1.5 (1.2–1.9); 1.7 (1.3–2.1)), change in residence at 3 and 6 months (1.6 (1.3–2.1); 1.3 (1.1–1.7)), and unemployment at 6 and 12 months (1.5 (1.1–2.1); 1.5 (1.1–2.1)). There was evidence of differences in post-stroke secondary prevention medication by ethnicity. Conclusion: We found ethnic disparities in care and outcomes following stroke which were independent of traditional risk factors, suggesting they may be attributable to stroke service delivery rather than patient factors.