Glycaemic control in type 2 diabetes: the impact of body weight, beta-cellfunction and patient education

We examined the determinants of glycaemic control in a consecutive cohort o f 562 newly-referred Chinese type 2 diabetic patients (57% women) during a 12-month period. All patients underwent a structured assessment with docume ntation of clinical and biochemical characteristics. Pancreatic beta-cell f unction was assessed by fasting plasma C-peptide concentration. Insulin def iciency was defined as fasting plasma C-peptide < 0.2 pmol/ml. Insulin resi stance (IR) was calculated using the homeostasis moder assessment (HOMA) ba sed on a product of fasting plasma glucose and insulin concentrations. Trea tment was considered appropriate when insulin-deficient patients were treat ed with insulin and non-insulin-deficient patients were treated with oral a gents or diet. Mean (+/-SD) age was 54.3 +/- 13.8 years (range 17-87 years) and disease duration was 5.0 +/- 5.9 years. At the time of referral, 70.5% (n = 396) were on drug therapy (9% on insulin and 62.8% on oral agents), 2 0.6% (n = 116) were on diet and 9% (n = 50) had not received any form of tr eatment. The mean HbA(Ic) was 8.4 +/- 2.3%. The geometric mean ( x / divide d by antilog SD) of IR was 4.62 x / divided by 2.51 (range 0.63-162.7) and correlated only with waist:hip ratio (WHR, p = 0.008). The geometric mean o f plasma C peptide was 0.47 x / divided by 2.89 nmol/l and correlated with BMI (p < 0.001). Glycated haemoglobin was correlated positively with age (p = 0.013), disease duration (p < 0.001), IR (p < 0.001) and negatively with EMI (p < 0.001). Glycated haemoglobin was lower in patients who had seen a dietitian (7.9% vs. 8.7%, p < 0.001) or diabetes nurse (7.8% vs. 8.7%, p < 0.001) or who performed self blood glucose monitoring (7.9% vs. 8.6%, p = 0.001) and higher among smokers (8.9% vs. 8.2%, p = 0.003). Compared to ins ulin-deficient patients (n = 118), non-insulin-deficient patients (n=413) h ad features resembling that of the Metabolic Syndrome with increased WHR (p = 0.005), brood pressure (p < 0.001), BMI (p = 0.001) and were order (p = 0.04). Amongst the insulin-deficient patients, 27% were treated with oral a gents or diet. Patients receiving appropriate therapy (n = 362) had a lower HbA(Ic) than those treated inappropriately (n = 173) (8.2% vs. 8.7%, p = 0 .02). On multivariate analysis, short disease duration (p < 0.001), row IR (p < 0.001), high BMI (p = 0.001), diabetes education (p < 0.001), rack of smoking (p = 0.014) and choice of appropriate treatment (p = 0.009) were th e independent determinants of good glycaemic control.