OBJECTIVES: Patients with diabetes are at high risk for coronary heart disease (CHD) and tight control of lipid levels is an important clinical objective. In this study, we assessed the rate of cholesterol goal attainment among patients with diabetes in a managed care setting. METHODS: A retrospective cohort design was employed using linked pharmacy, medical, and clinical laboratory data from members of a Northeastern US group model HMO. The study cohort included diabetes patients 55+ years of age without CHD who began lipid-lowering drug therapy between 1995 and 1998. Patients were required to have had an LDL-C value over 160 mg/dL within 90 days before beginning treatment. The change in LDL-C and the rate of NCEP ATP II goal attainment (LDL<130 mg/dL) were evaluated over 1 year. RESULTS: A total of 318 patients met study eligibility criteria. The average age was 68 years and 43% were male. The mean baseline LDL-C level was 195 mg/dL (± 28 mg/dL) and about 52% of patients had a baseline LDL-C level of 160-189 mg/dL. Ninety-four percent (n=298) of patients had =1 follow-up LDL-C measurements during follow up. The mean decline in LDL-C was 22% (± 14%). The ATP II treatment goal was reached by 36% of patients. About 50% of patients with baseline LDL-C of 160-189 mg/dL achieved goal versus 21% of patients =190 mg/dL. Better adherence to treatment (=50% of days covered) and more frequent monitoring of lipid levels were both positively associated with goal attainment. CONCLUSIONS: In the mid-to-late 1990s, most patients with diabetes treated for hyperlipidemia did not achieve their cholesterol goals. Recent guidelines (NCEP ATP III) have identified diabetes patients as a "CHD risk equivalent" with a lower cholesterol goal (LDL<100 mg/dL). Further research is warranted to identify steps for increasing treatment effectiveness in these patients.