Red cell distribution width: a measure of cardiovascular risk in rheumatoid arthritis patients?

This study aims to evaluate if myocardial infarction (MI) is more frequent in rheumatoid arthritis (RA) patients with elevated levels of red cell distribution width (RDW). Utilizing a secure cloud based platform, Explorys, we searched de-identified US patient data between 1999 and 2014. RA patients were identified by serologic positivity and ICD9 diagnosis code. Patients were stratified into high (≥15.6 %) RDW and low (<13.5 %) RDW groups (and excluding any patient with prior episode of RDW >15.6 %). The proportion of patients with diagnosis of MI in each RDW group was collected. For comparison, patients were divided into high and low CRP groups (≥2.5 and ≤0.8 mg/dL) and high and low ESR groups (≥50 and ≤30 mm/h), and MI data were collected. Statistical comparison between high and low laboratory test groups was performed with chi-square test, and odds ratios were calculated. The patient population included 20,810 patients with RA. The proportion of RA patients with MI was significantly increased in the high compared to low RDW, ESR, and CRP groups (p < 0.001 for each). The odds ratios of MI were greater in the high than in the low group for each parameter: RDW (OR1.5, 95 % CI 1.3 to 1.6); ESR (OR2.0, 95 % CI 1.8–2.3); and CRP (OR1.9, 95 % CI 1.7 to 2.2). These data from a large unselected population suggest that elevated RDW levels in RA patients should prompt physicians to aggressively screen and treat their patients for modifiable cardiovascular (CVS) risk factors, in addition to treating RA inflammation.