EDITORIAL - overlap between SLE and RA: is it real or just an illusion?

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Overlap Between Systemic Lupus Erythematosus and Rheumatoid Arthritis:

Is It Real or Just an Illusion?

LUIS M. AMEZCUA-GUERRA, MD,

Department of Immunology,

Instituto Nacional de Cardiolog¨ªa Ignacio Ch¨¢vez,

LaSalle University School of Medicine,

Badiano 1, Secci¨®n XVI,

Tlalpan, 14080, Mexico City, Mexico

ACKNOWLEDGMENT

I acknowledge Drs. Ang¨¦lica Vargas and Bojalil for their

critiques of this report.

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The association between rheumatoid arthritis (RA) and systemic lupus

erythematosus (SLE) has been debated for many years. Based on their

different genetic background and pathogenic mechanisms, it has been

argued that both diseases are complex, mutually exclusive entities.

However, recent knowledge is challenging this notion, suggesting that

both diseases can indeed overlap.

In this issue of The Journal, Icen and colleagues explore the

frequency of SLE features and their influence on mortality in an

incident cohort of 603 subjects with RA followed over time1. This

study was conducted in the Rochester Epidemiology Project, a

centralized medical record-linkage system that encompasses all

healthcare data from residents of Rochester and Olmsted County,

Minnesota, USA, since 1909. This kind of project provides an

extraordinary opportunity to conduct comprehensive population-based

studies over long periods. A cumulative incidence of ¡Ý 4 SLE features

(including arthritis) was found in 15.5% of patients after 25 years of

followup, this being associated with a 2-fold increase in the risk of

death.

Is there an explanation for the high incidence of SLE features found

in this cohort of RA patients? Information about SLE and RA

association is scarce and discrepant. Cohen and colleagues reported

that 11 of 309 (3.6%) patients with SLE fulfilled classification

criteria for RA, suggesting that both diseases are more frequently

associated than expected by chance2. In contrast, in a retrospective

study including about 7000 new patients, Panush and colleagues

identified only 6 patients with overlapping criteria for RA and SLE,

with a 10-fold lower concurrent prevalence rate (0.09%) than that

expected by chance (1.2%)3.

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Read the entire editorial here:

http://www.jrheum.com/subscribers/09/01/4.html

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