Rheumatoid arthritis (RA) patients frequently present subclinical myocardial inflammation, researchers recently discovered, and its presence correlates with RA disease activity.
For the study, 119 RA patients (mean age, 54 years; 82% were female; median disease duration, 6.7 years) without diagnosed cardiovascular disease (CVD) underwent cardiac 18-fluorodeoxyglucose positron emission tomography with computed tomography (FDG PET-CT). Standard uptake values (SUV) were used to evaluate myocardial FDG. At six months, eight patients who were undergoing disease modifying anti-rheumatic drug (DMARD) therapy had a follow-up FDG PET-CT scan to evaluate myocardial FDG uptake changes associated with treatment.
Myocardial FDG visually presented itself in 46 (39%) RA patients, of which just over half (n = 25, 54%) had focal uptake only, and a little less than half (n = 21, 45%) had any diffuse uptake (with diffuse, n = 15; with focal on diffuse, n = 6). Patients with visualized focal only uptake had a mean myocardial SUV mean 61% higher than patients with no visible uptake (2.80 vs. 1.74 units, P < 0.001). Patients with any visualized diffuse myocardial FDG uptake had a mean myocardial SUV 124% higher compared to patients with no visible uptake (3.89 vs. 1.74 units, P < 0.001). The mean of the maximum SUV in patients with focal uptake only was 98% higher than in patients who had no visible uptake (5.22 vs. 2.63 units, P < 0.001). For patients with any diffuse visible myocardial FDG uptake, the mean maximum myocardial SUV was 130% higher than in patients who did not have visual uptake (6.04 vs. 2.63 units, P < 0.001).
In univariate models, researchers found a significant correlation between non-Hispanic black race, increased body mass index (BMI), higher DAS28, and higher clinical disease activity index (CDAI) higher log mean SUV mean. Use of non-tumor necrosis factor (TNF) inhibitor biologics was greatly associated with a lower log mean SUV. In further analyses, only disease activity was significantly associated with a higher log mean SUV. When adjusting for BMI and CAC level, non-TNF inhibitor biologics were still linked with a lower log mean SUV. Among patients with a CDAI ≥ 10, the average adjusted mean SUV was 31% higher than in patients with a CDAI < 10 (2.30 vs. 1.76 units, P = 0.005). The non-TNF targeted biologics patients’ adjusted mean SUV was 26% lower compared with those not treated with biologics (1.65 vs. 2.23 units, P = 0.029).
“Importantly, we observed an association of myocardial inflammation with articular disease activity,” the researchers wrote. “This observation, which is consistent with several previous CMR studies supports the premise that achieving low disease activity or remission of RA activity protects not only the joints but possibly the myocardium as well.”
“In summary, although larger longitudinal data are needed, the current study supports the hypotheses that myocardial inflammation in RA is related to disease activity, that it may contribute to the increased risk for heart failure in patients with RA compared with controls, and that it may be responsive to step-up therapy,” the authors concluded.
Source: Arthritis & Rheumatology