Nephritis and the risk of acute myocardial infarction in patients with systemic lupus erythematosus.

BACKGROUNDS

Patients with systemic lupus erythematosus (SLE) have an increased risk of acute myocardial infarction (AMI). We examined if nephritis or other clinical manifestations of SLE identified patients at increased risk.

METHODS

In this population-based case-control study, we identified patients with SLE hospitalized with an AMI in California in 1996-2000. We compared the frequency of six manifestations of SLE (nephritis, pleuritis, hemolytic anemia, thrombocytopenia, psychosis/major depression, seizures) and of venous thrombosis/pulmonary embolism, in this group (n=535) to the frequency of these manifestations in two control groups: patients with SLE hospitalised for pulmonary disease (n=529), and patients with SLE hospitalised for gastrointestinal bleeding (n=349).

RESULTS

Nephritis was present in 23.7% of patients with AMI, 11.0% of patients with pulmonary disease and 25.2% of patients with gastrointestinal bleeding. In adjusted analyses, nephritis was more common in the AMI group (odds ratio (OR) 2.85, 95% confidence interval (CI) 1.97-4.14; p<.0001) than in the pulmonary disease control group. Among women, nephritis was more common in the AMI group (OR 2.83; 95% CI 1.33-6.01; p=0.007) than in the gastrointestinal bleeding control group. Psychosis/major depression was less common among patients with AMI.

CONCLUSIONS

Among patients with SLE, nephritis was associated with 2.8-fold increased risk of AMI.