Gender and the treatment of immune-mediated chronic inflammatory diseases: rheumatoid arthritis, inflammatory bowel disease and psoriasis: an observational study

Abstract

Background: Rheumatoid arthritis (RA), inflammatory bowel disease (IBD), and psoriasis are immune-mediated inflammatory diseases with similarities in pathophysiology, and all can be treated with similar biological agents. Previous studies have shown that there are gender differences with regard to disease characteristics in RA and IBD, with women generally having worse scores on pain and quality of life measurements. The relationship is less clear for psoriasis. Because treatment differences between men and women could explain the dissimilarities, we investigated gender differences in the disease characteristics before treatment initiation and in the biologic treatment prescribed.

Methods: Data on patients with RA or IBD were collected from two registries in which patients treated with biologic medication were enrolled. Basic demographic data and disease activity parameters were collected from a time point just before the initiation of the biologic treatment. For patients with psoriasis, the data were taken from the 2010 annual report of the Swedish Psoriasis Register for systemic treatment, which included also non-biologic treatment. For all three diseases, the prescribed treatment and disease characteristics were compared between men and women.

Results: In total, 4493 adult patients were included in the study (1912 with RA, 131 with IBD, and 2450 with psoriasis). Most of the treated patients with RA were women, whereas most of the patients with IBD or psoriasis were men. There were no significant differences between men and women in the choice of biologics. At treatment start, significant gender differences were seen in the subjective disease measurements for both RA and psoriasis, with women having higher (that is, worse) scores than men. No differences in objective measurements were found for RA, but for psoriasis men had higher (that is, worse) scores for objective disease activity measures. A similar trend to RA was seen in IBD.

Conclusions: Women with RA or psoriasis scored significantly higher on subjective, but not on objective, disease activity measures than men, and the same trend was seen in IBD. This indicates that at the same level of treatment, the disease has a greater effect in women. These findings might suggest that in all three diseases, subjective measures are discounted to some extent in the therapeutic decision-making process, which could indicate undertreatment in female patients.

Figure 1

Clinical characteristics just before treatment start in patients with inflammatory bowel disease (IBD). Values are means, and significant values are indicated by brackets. CRP, C-reactive protein; ESR, erythrocyte sedimentation rate; Hb, hemoglobin level; SHS, Short Health Scale.

Figure 2

Proportions of high Psoriasis Area and Severity Index (PASI) and Dermatology Life Quality Index (DLQI) scores in patients with psoriasis. Values are proportions, and significant values are indicated by brackets.