Register Trends and Survival Between Ethnic Groups After Stroke : The South London Stroke

Stroke is the fifth leading cause of death in low-income countries and the second in high-income countries after heart disease. Overall burden of disease data from the World Health Organization show stroke still in the top 6 based on disability adjusted life-years. Mortality rates for stroke are reported to be declining in western countries supposedly because risk reduction programmes are implemented, yet there are epidemics of obesity, and there has been migration of higher risk communities, such as people of African origin, where in the United States United Kingdom. With an ageing population, despite falling incidence rates, the numbers of strokes will increase as risk increases exponentially with age. Ethnic differences in stroke incidence, mortality, and survival have been reported with conflicting results showing the disadvantages or advantages of black patients over white patients. Bravata et al reported that blacks in the United States had a higher incidence of stroke and more severe strokes than whites, and ethnic differences existed in the prevalence of stroke risk factors. Kissela et al also reported that blacks have higher age-adjusted mortality rates than whites because of higher stroke incidence rates, particularly in the young and middle-aged in the United States. Cushman et al showed that blacks <75 years have more than twice the risk for stroke death than whites in the United States. Despite the commonly held belief that black patients have higher stroke mortality, several studies have reported better survival in black patients with stroke. Wolfe et al showed that black patients in a south London population were more likely to survive than white patients. Xian et al, based on the data from 164 hospitals in New York, also reported that among patients with acute ischemic stroke, black patients had lower mortality than white patients and concluded that this could be the result of differences in receipt of effective interventions. However, the studies to date generally lack data to minimize the effect of confounding. Few studies have compared the incidence and mortality of stroke in black and white people from the same population. Two population-based stroke registers in US cities, the Northern Manhattan Stroke Study (NOMASS) and The Greater Cincinnati/Northern Kentucky Stroke Study (GCNKSS), found twice the incidence of stroke adjusted for age and sex in black people than in white people, but did not find a significant difference between black people and white people in survival after stroke. The South London Stroke Background and Purpose—To identify trends and differences between ethnic groups in survival after first-ever stroke and examine factors influencing survival. Methods—Population-based stroke register of first in a lifetime strokes between 1995 and 2010. Baseline data were collection of sociodemographic factors, stroke subtype, case mix, risk factors before stroke, and receipt of effective acute stroke processes. Survival curves were estimated with Kaplan-Meier methods, and survival analyses were undertaken using Cox Proportional-hazards models. Results—Survival improved significantly over this 16-year period (P<0.0001). Black Caribbean and black African had a reduced risk of all-cause mortality compared with white patients (hazard ratio, 0.85 [95% confidence interval, 0.74–0.98] and 0.61 [0.49–0.77], respectively) after adjustment for confounders. This survival advantage of black Caribbean/black African over white mainly existed in older patients (over 65). Recent stroke, being black Caribbean/black African, and stroke unit admission were associated with better survival. Conclusions—Survival has improved in a multiethnic population over time. The independent survival advantage of black Caribbean and black African over White group in those aged over 65 may be a healthy migrant effect of first generation migrants. The increase in admission to a stroke unit may contribute to the improvement in survival after stroke. (Stroke. 2013;44:380-387.)