Objective: To determine the natural history of hypercholesterolemia in the first 3 years of disease in an inception cohort of patients with systemic lupus erythematosus (SLE) followed at a single center and to determine the influence of hypercholesterolemia on the subsequent development of coronary artery disease (CAD) related events.
Methods: We identified patients who were seen at the University of Toronto lupus clinic within 1 year of diagnosis from January 1, 1974, to December 31, 1987, and who were seen at least once a year in the first 3 years. Patients were divided into 3 groups: Normal cholesterol: serum total cholesterol (TC) < 5.2 mmol/l throughout the 3 year period of study. Sustained hypercholesterolemia: at least one measurement of TC of > 5.2 mmol/l in each of the first 3 years at the clinic. Variable hypercholesterolemia: TC > 5.2 mmol/l in no more than 2 of the first 3 years of followup. Patients were followed from inception until the present day. The primary outcome was the time of the first CAD related event (myocardial infarction, angina, or sudden unexplained death).
Results: One hundred thirty-four patients (118 women, 16 men) were studied: 33 (24.6%) had normal cholesterol, 54 (40.3%) had sustained hypercholesterolemia, and 47 (35.1%) had variable hypercholesterolemia. Using multiple logistic regression the best predictors of sustained hypercholesterolemia were cumulative dose of steroids, no antimalarial therapy, and age of onset of SLE > 35 years old. CAD related events occurred in 1 (3%) of the normal TC group, 3 (6.4%) of the variable group, and in 15 (27.8%) of the sustained group (p = 0.003), 79% of all CAD events occurred in the sustained group. The best predictors of CAD were sustained hypercholesterolemia, lung involvement, and age at onset of SLE > 35 years.
Conclusion: Within 3 years of diagnosis, 75.4% of patients with SLE had elevated TC, which was sustained in 40.3% of all patients. Older age at onset as well as increased cumulative dose of steroids and no antimalarial therapy are significant predictors of this group. It is this group that experiences the majority of CAD related events. Aggressive lipid lowering therapy should be targeted at such patients.