Aims To identify factors associated with insulin requirement in Type 2 diabetic patients, and to examine the significance of a normal plasma triglyceride level.
Methods One hundred and three poorly controlled (HbA1c = 9.4 ± 1.9%) Type 2 diabetic patients initially not treated with insulin were followed up for 5 years. Insulin was administered if HbA1c > 8% despite maximal oral anti-diabetic treatment and bodyweight control. Variables were compared between insulin requiring and non-insulin-treated patients using unpaired t-tests. The outcomes of initially normotriglyceridaemic (< 1.7 mmol/l) and hypertriglyceridaemic patients were compared using unpaired t-tests, and a survival analysis (Cox proportional hazards model).
Results Sixty-three patients were transferred to insulin. They were 5 years older (P = 0.004), with a 3-year longer duration of their diabetes (P = 0.03), a 1.2% higher HbA1c (P = 0.002), and 50% lower triglyceride levels (P = 0.02) than the others. The survival analysis showed that a long duration of diabetes, a high HbA1c, and a normal triglyceride level were associated with the need for insulin; the effect of normotriglyceridaemia was significant in the most poorly controlled (HbA1c > 9.5%) patients (relative risk: 2.35, 95% confidence interval: 1.16–5.52, P = 0.016). The 46 normotriglyceridaemic patients were leaner (P = 0.0004) and had lower C-peptide levels (P = 0.0008) than the others. Despite similar diabetes duration and HBA1c, more were transferred to insulin (normotriglyceridaemic: 71%, hypertriglyceridaemic: 52%, P = 0.03).
Conclusion A normal triglyceride level is associated with a need for insulin in poorly controlled Type 2 diabetes.