Ethnic and social disparity in glycaemic control in type 2 diabetes; cohort study in general practice 2004–9

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.