Ethnic differences in glycaemic control in adult Type 2 diabetic patients in primary care: a 3-year follow-up study

Objective To evaluate ethnic differences and characteristics related to glycaemic control in patients with Type 2 diabetes in primary care. Research design and methods Prospective cohort study; 500 adult patients with Type 2 diabetes, who were not on insulin therapy, were followed up annually for 3 years. HbA(1c) at baseline and 3-year changes and subsequent insulin therapy were related to baseline characteristics. Results Malay patients had significantly higher HbA(1c) (mean 8.7% +/- sd 1.66) compared with Chinese (8.2 +/- sd 1.67) and Indian (8.2 +/- sd 1.55) (P = 0.032) at baseline, and consistently for all years of HbA(1c) assessment (P = 0.017). At baseline, Malay patients were significantly more obese than Chinese or Indians (P < 0.001); fewer of them received structured shared-care intervention (P = 0.001), but they had a significantly higher glucose control educational score (P < 0.05). Multivariable analyses showed that HbA(1c) at baseline was significantly related to age (P = 0.001), BMI (P = 0.031) and ethnicity (P = 0.002). HbA(1c) declined significantly over 3 years in the whole population and in all ethnic groups. Significantly greater HbA(1c) declines were associated with higher baseline HbA(1c), structured shared-care intervention and non-insulin therapy. Correcting for differences on these factors, the decline in HbA(1c) in Malays was significantly less than in the Chinese. Insulin therapy was associated with higher baseline HbA(1c) and higher BMI. Conclusions Malay ethnicity was associated with persistently poor glycaemic control. Sociocultural and behavioural factors should be addressed in improving care for patients with poorly controlled diabetes.