Ethnic and immigrant disparities in dialysis prevalence and chronic kidney disease trajectories in Toronto

Large differences exist in chronic kidney disease (CKD) rates between countries, but differences within diverse populations living in the same setting with universal healthcare are not well understood.

To compare dialysis prevalence, CKD risk factors and control, and CKD progression by ethnicity and birth country in an ethnoculturally diverse setting with high rates of kidney disease and universal healthcare.

Scarborough, Toronto's most diverse region and site of Canada's largest regional dialysis programme.

Double observational cohort study of 2397 participants: a retrospective cohort of 1116 residents who received dialysis between 2016-2019, and a prospective cohort of 1281 individuals with non-dialysis CKD followed for 3 years between 2010-2015 in Scarborough.

Dialysis prevalence, calculated by comparing frequencies of birth countries and ethnicities in the dialysis cohort with census-derived community frequencies. Secondary outcome measurements were traditional CKD risk factor prevalence (diabetes, hypertension, cardiovascular disease) and control (haemoglobin A1c, blood pressure); and CKD progression (estimated glomerular filtration rate decline, proteinuria) adjusted for socioeconomic status in the non-dialysis cohort.

Dialysis prevalence was 4.2 times higher in immigrants (p<0.001), and highest in those born in the Caribbean, Southeast Asia and South Asia. Ethnicity-based differences were smaller, with rates up to 1.7-fold higher in Southeast Asian, Black and South Asian compared with White persons. Diabetes prevalence was highest in immigrants from South Asia, Southeast Asia and the Caribbean. Blood pressure and haemoglobin A1c were higher in Caribbean-born individuals. Kidney function declined fastest in patients born in the Caribbean, South Asia and East Asia. Proteinuria increased most rapidly in patients born in the Caribbean, Southeast Asia and South Asia. The year of immigration did not influence these secondary outcomes.

Despite universal healthcare access, marked disparities in CKD risks and rates exist within ethnoculturally diverse immigrants living in this Canadian kidney disease hotspot. More focused research and tailored interventions are required.