OBJECTIVES: In addition to elevated low-density lipoprotein cholesterol (LDL-C), studies have implicated decreased high-density lipoprotein cholesterol (HDL-C) and elevated triglycerides (TG) as independent modifiable risk factors for cardiovascular disease.  This study determined the proportion of patients with a single lipid abnormality (SLA) versus mixed dyslipidemia and their respective treatments among a large sample of managed care patients. METHODS: A retrospective cohort study of adults with a complete lipid panel between 1/1/2005 and 12/31/2008 in a US national health plan with >10 million commercial and Medicare Advantage members was conducted.  SLA was defined as one of the following: high LDL-C based on NCEP ATP III guidelines, low HDL-C (<40 mg/dL), or high TG (≥200 mg/dL).  Mixed dyslipidemia was defined as having ≥2 of the lipid abnormalities.  Proportion of patients with an SLA or mixed dyslipidemia and lipid-modifying therapy patterns were evaluated. RESULTS: A total of 247,322 patients had dyslipidemia in the 4-year observation period; 68% had an SLA and 32% had mixed dyslipidemia.  Of patients with SLA, 47% had elevated LDL-C, 32% had low HDL-C, and 21% had elevated TG.  For patients with an SLA, only 29% received lipid-modifying therapy, with 71% of those receiving statin monotherapy.  Of patients with mixed dyslipidemia, 42% had low HDL-C and high TG, 22% had high LDL-C and low HDL-C, 21% had high LDL-C and high TG, and 15% had all 3 abnormal lipid parameters.  In the mixed dyslipidemia group, only 33% received lipid-modifying therapy, with 58% of those receiving statin monotherapy and 19% receiving multi-pill combination therapy. CONCLUSIONS: The lack of treatment and inadequate treatment observed in this real-world study indicates an unmet medical need in managing lipid levels among dyslipidemic patients, including patients with mixed dyslipidemia.