Abstract
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.
Footnotes
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Supported by the Centre for Prognosis Studies in The Rheumatic Diseases, The Smythe Foundation, Ontario Lupus Association, Lupus Flare Foundation, and The Lupus Society of Alberta. Dr. Nikpour was supported by the Arthritis Centre of Excellence and the Geoff Carr Lupus Fellowship and currently holds a University of Melbourne Faculty of Medicine, Dentistry and Health Sciences David Bickart Clinician Researcher Fellowship.
- Accepted for publication August 13, 2013.