Effect of Combination Cholesterol-Lowering Therapy and Triglyceride-Lowering Therapy on Medical Costs in Patients With Type 2 Diabetes Mellitus.

High triglyceride (TG) levels among patients with type 2 diabetes mellitus (DM) are associated with higher medical costs. We analyzed the economic impact of TG-lowering therapies and whether the association between medical costs and therapy differed according to TG reduction. We conducted an observational cohort study of 184,932 patients with diabetes mellitus who had a TG measurement between January 2012 and June 2013 and a second TG measurement 3 to 15 months later. We identified 4 therapy groups (statin monotherapy, TG-specific monotherapy, statin/TG-specific combination therapy, or no therapy) and stratified those groups by percent change in TG (increased ≥5%, change of ≤4.9%, decreased 5% to 29%, decreased ≥30%). We compared change in medical costs between the year before and after therapy, adjusted for demographic and clinical characteristics. Of the 184,932 total patients, 143,549 (77.6%) received statin monotherapy, 900 (0.5%) received TG-specific monotherapy, 1,956 (1.1%) received statin and TG-specific combination therapy, and 38,527 (20.8%) received no prescription lipid agents. After covariate adjustment, statin/TG-specific agent recipients had a mean 1-year total cost reduction of $1,110. The greatest cost reduction was seen among statin/TG-specific combination therapy patients who reduced TG levels by ≥30% (-$2,859). Statin monotherapy patients who reduced TG by ≥30% also had a large reduction in adjusted costs (-$1,079). In conclusion, we found a substantial economic benefit to treating diabetic patients with statin/TG-specific combination lipid therapy compared with monotherapy of either type or no lipid pharmacotherapy. A TG reduction of ≥30% produced a particularly large reduction in 1-year medical costs.