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Rheumatoid arthritis factors equal to cardiovascular factors in risk of severe cardiovascular events

June 16, 2008

Certain cardiovascular disease (CVD) risk factors and rheumatoid arthritis (RA) disease factors have a similar effect on an RA patient's risk of experiencing myocardial infarction (MI) or stroke, according to a new study presented today at EULAR 2008, the Annual Congress of the European League Against Rheumatism in Paris, France.

The researchers studied 10,870 RA patients for a median of 24 months across two cohorts - patients with active RA and those with prior experience of CVD. Cox regression models revealed that the CVD risk factors leading to an increased relative risk of MI or stroke were: non-Caucasian ethnicity (relative risk (RR) 1.26), body mass index (RR 1.25), prior MI (RR 1.75), and any current tobacco use (RR 1.92). The RA disease factors leading to an increased relative risk of MI or stroke were: nodules (RR 1.44), Health Assessment Questionnaire Disability Index (HAQ-DI) (RR 1.20 per each point increase) and the Clinical Disease Activity Index (CDAI) (RR 1.06 per each point increase). The area under the receiver operating characteristic curve (c-statistic) of the CVD risk factor and RA disease factor models (adjusting for age and gender) were both calculated as 0.75, demonstrating a comparable relationship with CVD endpoints for both RA and CVD risk factors..

Lead investigator, Professor Daniel H Solomon of Brigham and Women's Hospital and Harvard Medical School, Boston, USA, said: "It has been established that people with RA are more likely to experience cardiovascular disease or complications than the general population, but our research examines the importance of RA-specific factors compared with traditional cardiovascular risk factors. We have shown that having more high risk RA-specific risk factors increases the CVD risk to a rate similar to that of traditional cardiovascular risk factors. We hope that the results of our study lead to more robust clinical prediction rules for CVD outcomes in RA along with appropriate management and treatment options for the future."

All data were taken from the Consortium of Rheumatology Researchers of North America, Inc. (CORRONA) independent registry, the largest physician-based RA registry in the US, which carries information on over 15,000 patients with RA and other rheumatic conditions. Records for patients who had made at least two visits to healthcare facilities were selected and information about CVD risk factors, with RA disease factors drawn from baseline questionnaires.

CVD outcomes included MI, stroke and transient ischemic attack, reported and then confirmed by the treating rheumatologist. CVD risk factors included a history of coronary artery disease or MI, diabetes, hypertension, family history of premature MI, body mass index, dyslipidemia (assessed as use of a lipid-lowering agent), non-Caucasian ethnicity, and current tobacco use.

RA disease factors included duration of RA, rheumatoid factor status, HAQ, CDAI, subcutaneous nodules, Sjogrens (an autoimmune condition associated with arthritis), tender joint count, swollen joint count, and total joint replacements. These variables were assessed as predictors of CVD outcomes in separate Cox regression models, with age and gender included in both. Finally, the discriminatory value of these variables was assessed by calculating the area under the receiver operating characteristic curve (C statistic) in logistic regression.

European League Against Rheumatism