Patients with rheumatoid arthritis (RA) have excess morbidity and mortality due to ischemic heart disease. It has been suggested that high serum levels of mannose-binding lectin (MBL) and agalactosyl IgG (IgG-G0) are associated with increased inflammation in RA. MBL also enhances inflammation-mediated tissue injury during postischemic reperfusion. This study was undertaken to examine whether these factors are associated with increased risk of ischemic heart disease in RA.
MBL alleles were genotyped in 229 Danish patients with RA. In addition, serum levels of MBL and IgG-G0 were measured. Incidences of ischemic heart disease, myocardial infarction, and death due to ischemic heart disease after the diagnosis of RA were assessed in a prospective study.
During a median followup of 9.5 years, ischemic heart disease was diagnosed in 8 of 27 patients with genetically determined high serum levels of MBL, as compared with 24 of the remaining 192 patients (data not available on 10 patients). After correction for other known risk factors, the hazard ratio (HR) was 3.6 (95% confidence interval [95% CI] 1.4-9.2). The corrected HR for myocardial infarction was 9.0 (95% CI 2.2-36.4). High serum levels of MBL also conferred an increased risk of death due to ischemic heart disease (age- and sex-adjusted HR 10.5, 95% CI 2.7-41.3). However, further analyses showed that these associations were present only in patients with high serum levels of IgG-G0.
Genetically determined high serum levels of MBL and high serum levels of IgG-G0 are associated with increased risk of ischemic heart disease, myocardial infarction, and premature death in patients with RA.