Co-morbidity index in rheumatoid arthritis: time to think.

Rheumatoid arthritis patients are clinically complex, and the interplay of their disease activity together with the other associated conditions may lead to increased morbidity and mortality. The recent advances in the disease management attracted the attention to its associated co-morbidities and highlighted the need for a tool to provide clinicians and potential payers with a clinically powerful measure of the disease burden and prognosis. Predicting outcome or co-morbidity probability has been previously implemented successfully for calculating 10-year fracture probability (FRAX) as well as for predicting 1-year patient mortality using co-morbidity data obtained (Charlson index). Developing a specific rheumatoid arthritis-independent tool able to predict morbidity, mortality, cost and hospitalization would be a step forward on the way to achieve full disease remission. The co-morbidity index should be used both at baseline as well as a continuous variable in analyses. It should be implemented regularly in the clinical assessment as a confounder of outcomes. This article will review the redefined health outcomes in rheumatoid arthritis and the concept of co-morbidity index for patients with inflammatory arthritis. It will also present a proposed co-morbidity index for rheumatoid arthritis patients.