Introduction:

In patients with rheumatoid arthritis (RA), disease activity is often determined through the DAS28 index. Subjective components included in the index can be influenced by non-inflammatory factors, and overestimate disease activity. The DAS28 index and its subjective components have not been extensively studied in South Americans.

Objectives:

Analyze the subjective components of DAS28 as well as clinical and serological variables related to it in South American patients with rheumatoid arthritis treated with biologics.

Methods:

Retrospective longitudinal analysis of patients from BIOBADAGUAY registry. The formula for the subjective component of DAS28 was determined. DAS28 and its components were analyzed for both populations at treatment initiation, and 52 week follow up, and associations with clinical and serological variables were evaluated.

Results:

The Paraguayan patients had lower mean age, number of comorbidities and less smokers. They were also found to have lower DAS28, sDAS28, PGH and TJC. Country of origin, number of comorbidities, BMI, smoking history and methotrexate use were associated to subjective components of DAS28 at treatment initiation. Changes in sDAS28 at week 52 were highly determined by its initial value. No association was found with objective variables (CRP, ESR, number of treatments.)

Conclusions:

Variables other than inflammatory disease activity can influence sDAS28 and DAS28 of South American patients. Their management must be individualized and not be based solely on DAS28 value.

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