Stroke recurrence among South Asians with diabetes in Ontario, Canada

Background — South Asians have more vascular risk factors, earlier cardiovascular disease onset, and higher stroke mortality than non-South Asians. However, ethnic differences in long-term outcomes post-stroke in diabetics are unclear.

Aims — We compared cardiovascular outcome risk after first ischemic stroke between South Asian and non-South Asian diabetics.

Methods — Using population-based healthcare databases in Ontario, Canada, we selected all patients with diabetes hospitalized with first ischemic stroke between 1 April 2002 and 31 March 2012, and assigned South Asian versus non-South Asian ethnicity using a validated surname algorithm. Kaplan-Meier survival analysis estimated survival functions, and competing risk models estimated hazards of death, stroke, and myocardial infarction. The primary predictor was ethnicity, and models were adjusted for demographics and vascular risk factors. Sensitivity analysis including adjustment for medication use was performed in those aged ≥65 years.

Results — There were 25,495 diabetics with first ischemic stroke; 840 were South Asian. South Asians were younger, more often male, had lower income, and had shorter Ontario residency compared to non-South Asians. South Asians had higher incidence and cumulative risk of recurrent stroke. In fully adjusted competing risk models, recurrent stroke rate was increased among South Asians compared to non-South Asians (HR 1.17 [95% CI 1.00-1.38]) in the whole cohort and in those aged ≥65 years, both with adjustment for medication use (HR 1.23 [1.01-1.50]) and without (1.27 [1.04-1.54]).

Conclusions — In this large population-based study, South Asian diabetic stroke patients had higher recurrent stroke rates compared to non-South Asians, despite a younger age profile. Further research is needed to reduce stroke burden in South Asians.