Coronary microvascular dysfunction in rheumatoid arthritis compared to diabetes mellitus and association with all‐cause mortality

OBJECTIVE: Coronary microvascular dysfunction (CMD) is a predictor of cardiac death in diabetes mellitus (DM), independent of traditional cardiovascular (CV) risk factors. Rheumatoid arthritis (RA) is a chronic inflammatory condition with excess CV risk compared to the general population, where CMD is hypothesized to play a role. However, there are limited data on CMD in RA and association with clinical outcomes. The objective of this study was to compare the prevalence of CMD in RA to DM, and test association with all-cause mortality. METHODS: We performed a retrospective cohort study using data from a registry of all patients undergoing stress myocardial perfusion positron emission tomography (PET) as part of routine clinical care from 2006-2017. Inclusion criteria was a normal perfusion scan. RA or DM patients were classified using previously published approaches. Coronary flow reserve (CFR) was calculated on all patients in the registry and linked with mortality data. CMD was defined as CFR<2.0. RESULTS: We studied n=73 patients with RA, and n=441 with DM. Among patients with a normal perfusion scan, the prevalence of CMD in RA was similar to DM, p=0.2. CMD was associated with increased risk for all-cause mortality in RA (HR 2.4, 95% CI 1.4, 4.2), as well as increased risk for cardiac related death at rates similar to DM. CONCLUSIONS: These findings suggest an important role for CMD as a potential contributor to excess CV risk and mortality in RA, as previously observed in DM, as well as evidence for a mechanistic link between inflammation and CVD.