Ethnicity and sex affect diabetes incidence and outcomes

Abstract

Objective: Diabetes guidelines recommend aggressive screening for type 2 diabetes in Asian patients because they are considered to have a higher risk of developing diabetes and potentially worse prognosis. We determined incidence of diabetes and risk of death or macrovascular complications by sex among major Asian subgroups, South Asian and Chinese, and white patients with newly diagnosed diabetes.

Research design and methods: Using population-based administrative data from British Columbia and Alberta, Canada (1997-1998 to 2006-2007), we identified patients with newly diagnosed diabetes aged ≥35 years and followed them for up to 10 years for death, acute myocardial infarction, stroke, or hospitalization for heart failure. Ethnicity was determined using validated surname algorithms.

Results: There were 15,066 South Asian, 17,754 Chinese, and 244,017 white patients with newly diagnosed diabetes. Chinese women and men had the lowest incidence of diabetes relative to that of white or South Asian patients, who had the highest incidence. Mortality in those with newly diagnosed diabetes was lower in South Asian (hazard ratio 0.69 [95% CI 0.62-0.76], P < 0.001) and Chinese patients (0.69 [0.63-0.74], P < 0.001) then in white patients. Risk of acute myocardial infarction, stroke, or heart failure was similar or lower in the ethnic groups relative to that of white patients and varied by sex.

Conclusions: The incidence of diagnosed diabetes varies significantly among ethnic groups. Mortality was substantially lower in South Asian and Chinese patients with newly diagnosed diabetes than in white patients.

Figure 1

A: Age-adjusted incidence of diagnosed diabetes by ethnicity in women aged ≥35 years (1999–2003). B: Age-adjusted incidence of diagnosed diabetes by ethnicity in men aged ≥35 years. ▴, South Asian; ○, white; ●, Chinese.