Assessment of coronary risk based on cumulative exposure to lipids in systemic lupus erythematosus.

OBJECTIVE

To quantify the independent role of each of low-density lipoprotein cholesterol (LDL-C), total cholesterol:high-density lipoprotein cholesterol ratio (TC:HDL-C), triglyceride (TG) level, and HDL-C as a marker of coronary risk in systemic lupus erythematosus (SLE).

METHODS

Patients with lipid measurements taken before a coronary event (or last clinic visit) were included. Mean and time-adjusted mean (TAM) levels were calculated for each lipid variable in each patient. Time-dependent proportional hazards regression models were used to quantify the risk of coronary event [myocardial infarction (MI) or angina], after adjustment for age.

RESULTS

Among 384 patients, over a mean (SD) followup of 3.81 (2.58) years, there were 21 "first" coronary events (6 MI, 15 angina). Mean and TAM LDL-C (HR 1.83, 95% CI 1.19-2.81, p = 0.006), TC:HDL ratio (HR 1.43, 95% CI 1.02-2.00, p = 0.04), and TG (HR 2.11, 95% CI 1.32-3.39, p = 0.0019) were predictive of coronary event at subsequent visits. In contingency table analysis, TAM LDL-C cutpoint of 2.0 mmol/l had a sensitivity and negative predictive value for coronary event of 85.7% (95% CI 63.7-97.0) and 93.9% (95% CI 83.1-98.7), respectively. However, at this cutpoint the specificity was only 12.7% (95% CI 9.4-16.5).

CONCLUSION

This study links LDL-C, TC:HDL-C ratio, and TG to coronary risk in patients with SLE and quantifies the magnitude of this risk. SLE-specific risk assessment levels for lipids may be selected to optimize positive or negative predictive values.