Overtreatment and undertreatment of hyperlipidemia in the outpatient setting.

BACKGROUND: National guidelines recommend lipid-lowering therapy for patients with coronary heart disease (CHD), its equivalent (eg, diabetes mellitus, peripheral arterial disease, cerebrovascular disease), and those at high risk of CHD. Quality-of-care studies demonstrate that patients at high risk of CHD are undertreated. Overtreatment of patients at low risk of CHD remains relatively unexplored. Our study aimed to determine patient characteristics associated with under- and overtreatment of hyperlipidemia.
METHODS: We conducted a retrospective chart review of patients aged 35 to 80 years attending an inner-city ambulatory teaching clinic. We noted patients' 10-year cardiovascular risk based on the Framingham Heart Study equation, other patient demographics, pretreatment lipid levels, and whether they received a prescription for lipid-lowering therapy.
RESULTS: Of 676 patients included, 46% were at high (>15% for 10 years) and 37% were at low (<5%) risk. Of the patients at high risk for CHD, 34% received no drug therapy, including 5% of patients with known CHD; 37% of patients with diabetes mellitus; and 59% of patients without CHD equivalents. Undertreatment was associated with lower low-density lipoprotein (LDL; odds ratio [OR] per 30 mg/dL 2.7, confidence interval [CI] 2.0-3.6), fewer risk factors (OR per risk factor 1.5 CI 1.1-2.1), and not receiving other preventive care interventions (OR 2.1, CI 1.0-4.5). Of 247 patients at low risk for CHD, 8% received drug therapy. Overtreatment was associated with higher LDL (OR per 30 mg/dL 3.0, CI 1.7-5.3) and more cardiac risk factors (OR per risk factor 3.1, CI 1.4-6.7). Age, race, sex, and specific risk factors were not associated with overtreatment or undertreatment.
CONCLUSIONS: Both overtreatment and under-treatment are common. Physicians' decisions appear to reflect LDL values and number of risk factors rather than calculated cardiovascular risk.