Cardiovascular Complications and Mortality After Diabetes Diagnosis for South Asian and Chinese Patients

Abstract

OBJECTIVEMany non-European ethnic groups have an increased risk for diabetes; however, the published literature demonstrates considerable uncertainty about the rates of diabetes complications among minority populations. The objective of this study was to determine the risks of cardiovascular complications and of mortality after diabetes diagnosis for South Asian and Chinese patients, compared with European patients.RESEARCH DESIGN AND METHODSA population-based cohort study identified all 491,243 adults with newly diagnosed diabetes in Ontario, Canada, between April 2002 and March 2009. Subjects were followed until March 2011 for the first occurrence of any cardiovascular complication of diabetes (coronary artery disease, stroke, or lower-extremity amputation) and for all-cause mortality. Median follow-up was 4.7 years.RESULTSThe crude incidence of cardiovascular complications after diabetes diagnosis was 17.9 per 1,000 patient-years among European patients, 12.0 among South Asian patients, and 7.7 among Chinese patients. After adjusting for baseline characteristics, the cause-specific hazard ratios (HRs) for cardiovascular complications relative to European patients were 0.95 (95% CI 0.90–1.00; P = 0.056) and 0.50 (0.46–0.53; P < 0.001) for South Asian and Chinese patients, respectively. Mortality was lower for both minority groups (adjusted HR for South Asian patients 0.56 [95% CI 0.52–0.60]; P < 0.001; for Chinese patients 0.58 [0.55–0.62]; P < 0.001).CONCLUSIONSChinese patients were at substantially lower risk than European patients for cardiovascular complications after diabetes diagnosis, whereas South Asian patients were at comparable risk. Mortality after diabetes diagnosis was markedly lower for both minority populations.

Risk of Dementia in Seniors With Newly Diagnosed Diabetes: A Population-Based Study

“…Among individuals with diabetes, we also captured information on ethnicity using a validated algorithm that uses surnames to identify those of South Asian or Chinese heritage, and on immigration status using Canadian Citizenship and Immigration data (25,26). We also captured information on the use of statins and antihypertensive drugs (ACE inhibitors, angiotensin receptor blockers, diuretics, and calcium channel blockers [CCBs]) and antidiabetic treatment (metformin, sulphonylureas, or insulin) from the Ontario Drug Benefit Database, which contains records for all prescriptions filled by Ontario seniors.…”

Cardiovascular Disease in South Asian Migrants

“…25 However, there is some evidence that SA have equivalent or lower risk of CVD and mortality compared to Europids after a diagnosis of DM is made. 20,63,64 In a provincewide study in Ontario, Canada, SA patients with a new diagnosis of DM had a standardized incidence of 16.8 cardiovascular events per 1000 patient years compared to 17.9 per 1000 among Europids (p=0.06) 63. Nijjar and colleagues found that SA migrants in Canada with DM had lower long term mortality when compared to Europids (HR 0.62,…”

Comment on Shah et al. Cardiovascular Complications and Mortality After Diabetes Diagnosis for South Asian and Chinese Patients: A Population-Based Cohort Study. Diabetes Care 2013;36:2670–2676

“…Shah et al (1) suggest that the consequences of new-onset diabetes may be less severe in South Asian and Chinese patients and accounts for equivalent (South Asians) or lower (Chinese) risks of cardiovascular disease compared with Europeans with diabetes. They claim that missing data on key cardiovascular disease risk factors, in particular smoking, could not account for such ethnic differences.…”