Risk of coronary heart disease and stroke in a large British cohort of patients with systemic lupus erythematosus

OBJECTIVES: Patients with systemic lupus erythematosus (SLE) are at increased risk of myocardial infarction and stroke. We sought to determine how much of this risk was dependent on recognized cardiovascular risk factors. METHODS: Initially a software package 'Cardio-Risk-Manager', which utilizes Framingham data, was used to calculate a 10-yr risk of coronary heart disease (CHD) and stroke for 202 patients with SLE (Group 1) in comparison with hypothetical age- and sex-matched comparators. Subsequently 47 patients who had been followed since 1991 (Group 2) were studied to compare their predicted risks in 1991 with the actual number of cardiovascular events that occurred during the subsequent decade. RESULTS: Patients in Group 1 had a higher predicted 10-yr risk of stroke (P<0.0001), but not of CHD, than their comparators. However, following age stratification, traditional risk factors predicted a higher risk of CHD (P<0.0001) and of stroke (P<0.0001) in patients under 40 with SLE compared with age-matched comparators. The predicted 10-yr risks of CHD and stroke for patients aged 40 and above were not significantly different from those of their comparators. Predicted risks, however, were lower than the true 10-yr event rate for CHD and stroke in patients in Group 2. In this group, during the 10 yr of follow-up four patients (8.5%) suffered a CHD event and five patients (10.6%) had a stroke, significantly more than were predicted by the presence of conventional risk factors (P<0.001 for CHD and P<0.001 for stroke, respectively). CONCLUSIONS: Conventional risk factors predicted an increased risk of stroke and CHD in younger patients. They do not, however, fully explain the high risk of cardiovascular disease in patients with SLE. Although it is important to address the management of orthodox risk factors for cardiovascular disease in patients with SLE, other causes must be sought to explain the increased incidence of CHD and stroke, especially in those aged over 40.