A 52-year-old man with a 10-year history of type 2 diabetes and hypertension presents to the outpatient clinic. His lipid panel shows total cholesterol 285 mg/dL, LDL-C 180 mg/dL, HDL-C 35 mg/dL, and triglycerides 320 mg/dL. He is currently on metformin and amlodipine. His 10-year cardiovascular risk is estimated at 18%. Physical examination reveals xanthomas on the Achilles tendon and dorsal hands. What is the most appropriate next step in management?