The relationship between nonfasting and fasting lipid measurements in patients with or without type 2 diabetes mellitus receiving treatment with 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors.

BACKGROUND

Studies have confirmed a lack of patient and physician adherence to the revised National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) guidelines. These guidelines state that lipid panels should be obtained while the patient is in the fasting state. However, this restriction may limit the ordering of these tests and thus decrease the number of patients on drug therapy and the number treated until goal cholesterol levels are reached. Evidence shows that testing in the nonfasting state may not be clinically or significantly different from testing in the fasting state in identifying patients at risk for a future cardiovascular event.

OBJECTIVES

The purpose of this study was to determine whether a relationship exists between nonfasting and fasting lipid values in diabetic or nondiabetic patients that will permit the more ready identification of patients who require treatment to meet NCEP ATP III guidelines. A secondary goal was to determine whether diabetic patients who appear to have reached goal cholesterol levels in the fasting state meet those goals when the non-high-density lipoprotein cholesterol (HDL-C) levels are measured in the nonfasting state.

METHODS

This observational study was conducted at Androscoggin Cardiology Associates (Auburn, Maine). Patients with hyperlipidemia receiving statin therapy whose doses had not changed for > or =2 months were enrolled. For all patients, nonfasting and fasting lipid panels (total cholesterol, triglycerides [TGs], and HDL-C) were calculated, whereas low-density lipoprotein cholesterol (LDL-C)levels were measured directly. The direct LDL-C method was used to determine the variance of the calculated LDL-C from the actual value.

RESULTS

One hundred consecutive hyperlipidemic patients were tested. Patients included 70 men and 30 women, with a mean (SD) age of 66.2 (12.0) years(range, 24-93 years). Eighteen patients had type 2 diabetes mellitus (DM). Non-fasting TG, HDL-C, and LDL-C levels were able to identify almost all patients who did not meet ATP III guidelines in terms of cholesterol levels (95%, 100%, and 95%, respectively). No predictive differences were found, regardless of whether the patients had type 2 DM. For the total population, statistically significant differences were found between calculated nonfasting and fasting measurements for mean (SD)LDL-C levels (90.2 [24.8] mg/dL vs 99.7 [26.1] mg/dL, respectively; P < 0.001). The regression equation was fasting LDL-C = 22.7 + 0.854 x nonfasting LDL-C.A nonfasting LDL-C level >130 mg/dL predicted a fasting LDL-C level >100 mg/dL(95% CI, -12.79 to -6.24), and a nonfasting LDL-C level >130 mg/dL predicted cases of fasting LDL-C level >100 mg/dL (95% CI, -5.79 to -1.35).

CONCLUSIONS

In this study population, nonfasting TG, HDL-C, and LDL-C levels successfully identified almost all patients who did not meet ATP III guidelines for cholesterol levels. No clinically significant difference was found in diabetic or nondiabetic patients.