Aims: Little information is available on the association between obesity at time of insulin initiation and attainment of glycaemic targets in type 2 diabetic (T2DM) patients. This study describes changes in HbA1c, weight and body mass index (BMI) over 24 months postinsulin initiation.
Methods: First-time insulin users with T2DM were selected from the UK General Practice Research Database for the period 1st January 2002 to 31st March 2008. The cohort was stratified into BMI categories (kg/m(2) ) at the time of insulin initiation. Data were reviewed at 6-monthly intervals. A multivariate repeated-measures linear model was fitted assessing weight change over 12 months.
Results: 3783 patients were included (normal weight, n = 672; overweight, n = 1259; obese, n = 1070; clinically obese, n = 480; morbidly obese, n = 302). The largest reductions in HbA1c were observed 6 months postinsulin initiation and were greatest in lower BMI categories: median observed HbA1c at initiation and 6 months was 9.7 and 7.9% in normal weight patients and 9.6 and 8.2% in the clinically obese, respectively. A minority of patients achieved HbA1c ≤ 7.5% and by 24 months the proportion achieving this was: normal weight 41%; overweight 34%; obese 30%; clinically obese 26%; morbidly obese 31%; trend p < 0.001. The greatest weight gain occured by 6 months and multivariate adjusted models showed that normal weight patients had the highest gains 5.07 kg (95% CI: 3.35, 6.79), as did those with HbA1c ≥ 12.1%-5.55 kg (95% CI: 3.81, 7.28).
Conclusion: Obesity is associated with a poorer response to insulin illustrated by higher HbA1c values and lower achievement of targets.
© 2011 Blackwell Publishing Ltd.