Abstract
OBJECTIVE: To determine whether ethnic group differences in glycated haemoglobin (HbA1c) changed over a 5-year period in people on medication for type 2 diabetes. DESIGN: Open cohort in 2004-9. SETTING: Electronic records of 100 of the 101 general practices in two inner London boroughs. PARTICIPANTS: People aged 35 to 74 years on medication for type 2 diabetes. MAIN OUTCOME MEASURES: Mean HbA1c and proportion with HbA1c controlled to ≤ 7.5%. RESULTS: In this cohort of 24,111 people, 22% were White, 58% South Asian and 17% Black African/Caribbean. From 2004 to 2009 mean HbA1c improved from 8.2% to 7.8% for White, from 8.5% to 8.0% for Black African/Caribbean and from 8.5% to 8.0% for South Asian people. The proportion with HbA1c controlled to 7.5% or less, increased from 44% to 56% in White, 38% to 53% in Black African/Caribbean and 34% to 48% in South Asian people. Ethnic group and social deprivation were independently associated with HbA1c. South Asian and Black African/Caribbean people were treated more intensively than White people. CONCLUSION: HbA1c control improved for all ethnic groups between 2004-9. However, South Asian and Black African/Caribbean people had persistently worse control despite more intensive treatment and significantly more improvement than White people. Higher social deprivation was independently associated with worse control.