A 48-year-old woman from Mumbai with a 15-year history of poorly controlled type 2 diabetes (HbA1c 9.1%) and obesity (BMI 34 kg/m²) presents for lipid management. She is currently on metformin and glibenclamide. Fasting lipid panel shows: total cholesterol 310 mg/dL, LDL-C 220 mg/dL, HDL-C 28 mg/dL, triglycerides 480 mg/dL. She is started on atorvastatin 80 mg daily. After 8 weeks of therapy with good adherence, LDL-C falls to 140 mg/dL, but triglycerides remain elevated at 420 mg/dL. Liver function tests and creatinine kinase are normal. Which of the following best explains the persistent hypertriglyceridaemia despite statin monotherapy in this patient?