OP-0139 – Influence of Gender on Assessments of Disease Activity and Function in Rheumatoid Arthritis in Relation to Radiologic Damage Over the First Five Years of Disease

Svensson, Ahlmen, Albertsson, Forslind, Hafstrom; Lund, Sweden

Jon Giles

Objectives

There is uncertainty as to whether true gender differences exist for disease activity and long-term outcomes in RA patients, or whether apparent differences in outcomes may be an artifact of gender differences in the reporting of subjective outcomes.

Methods

Men and women enrolled in an inception cohort of early RA (the BARFOT study) were followed at one, two, and five years with measures of disease activity (the DAS28 score), physical function (HAQ and Signal of Functional Impairment (SOFI) Index, a measure of hand function) and radiographic damage.  Differences in scores for the components of these outcomes were compared between men and women.

Results

There were 343 women and 206 men included in the study.  Women were younger than men at baseline (54 vs. 61 years), but had similar duration of RA at enrollment (6 months for both).  At all time points, women had higher DAS28 scores compared to men.  These differences were entirely accounted for by higher tender joint counts in women and never because of gender differences in swollen joint counts.  Likewise, HAQ scores were always higher in women at all time points, dependent on reaching and gripping subscales, but never on dressing or rising.  In contrast, SOFI hand and upper extremity function scores tended to be higher in men than women.  Importantly, there was no difference in Sharp radiographic damage scores at follow-up between genders—consistent with the observation that predictors of radiographic damage (i.e. swollen joint count and ESR) were not the components of the DAS28 that differed between men and women.

Conclusions

Gender differences in outcomes between women and men with RA were secondary to gender differences in subjective reporting of specific components of outcome measures and may not represent differences in underlying disease activity or severity.

Editorial Comment

These findings highlight potential limitations of RA disease activity measures to indicate disease activity and predict damage.  The reasons behind the differences are likely multifactorial.  Differences in reporting of tender joints could be secondary to higher perception of joint pain in women for a given amount of swelling, or that men consistently under-report joint tenderness.  Likewise, men may under-report difficulties with physical function or, because of higher muscle mass and greater physical strength, in general, may not experience the same impact of RA disease activity on physical functioning compared to women.  Regardless, these differences do not appear to affect radiographic damage outcomes, which is reassuring as it suggests that treatment regimens need not necessarily be tailored to gender despite differences in some subjective symptoms.