Rheumatoid arthritis (RA) is associated with increased incidence cardiac failure. It is yet unclear how much the increased incidence is secondary to ischaemic damage, or whether inflammatory cytokines might have a direct effect on the myocardium.
To establish if patients with active rheumatoid arthritis but no history of cardiac disease have higher serum levels of brain natriuretic peptide (BNP), than patients with less active RA, or disease-free controls.
90 patients with RA and 31 healthy control subjects were recruited. Each was screened to exclude previous history of cardiac disease. RA disease activity was measured using the DAS28 assessment, and other demographic, physical and laboratory tests performed. Serum BNP levels were measured in all subjects.
There was no difference in the age, percentage females or BMI between the RA and control subjects. Median BNP in the RA patients was 80.0 pg/ml (IQR 38.0-132.0) compared with 48.5 (26.0-86.0) in the control subjects (p=0.017). There was a significant correlation between DAS28 and serum BNP in the RA group, r=0.37, p<0.01. RA patients were divided into three groups according to DAS28 scores. Patients with very active disease (DAS28>5.1) had significantly higher BNP levels than patients with moderately active disease (3.2<DAS28<5.1) or inactive disease (DAS28<3.2) (both p<0.01). Median BNP of RA patients with inactive disease did not differ from Controls.
RA patients with no history of cardiac disease have higher serum BNP levels than healthy control subjects. RA patients with active RA have higher BNP levels than RA patients with moderately active or inactive disease, raising the possibility of a directly depressive effect of inflammatory cytokines on the myocardium.