Gender Differences in Clinical and Radiographic Presentations of Ankylosing spondylitis

Abstract

Objective: Ankylosing spondylitis (AS) is a chronic inflammatory disease that primarily affects the spine, peripheral entheses and peripheral joints, and is more prevalent in males than females. This study compared the differences between male and female patients with AS in possible risk factors, clinical manifestations, laboratory markers, radiographic changes, functional outcomes, and treatment in AS. Methods: AS patients were enrolled from rheumatologic clinics of a tertiary medical center. Direct interview, clinical evaluation, and chart review were used to collect the personal demographics, clinical symptoms/signs, Bath AS indices, HLA-B27, inflammatory markers, radiographic findings and treatment history. Findings were stratified by gender. Results: The study included 179 AS patients (148 males and 31 females). The age and duration of disease were not different between genders. However, females were older at disease onset (females 26.3 ± 10.2 years, males 21.0 ± 8.2 years, p=0.009), and had a longer time delay to diagnosis (females 5.7 ± 7.1 years, males 5.0 ± 7.8 years, p=0.011) as compared to males. In both groups, the axial joints were the most common of the first manifestation of AS. During similar disease duration, females had equal axial joint involvement, and more sausage digits, knee enthesopathy, hand and temporomandibular joint arthritis, but less hip arthritis on any occasion. Females were similar or better than males with regards to functional outcomes evaluated with Bath AS Functional Index (BASFI) and Bath AS Metrology Index (BASMI). Besides, the radiographic changes of female patients versus males were less in sacroiliac joints, spine and hip joints. Conclusions: In this study, female and male AS patients had different clinical manifestations. Females had more involvement in some peripheral joints and entheses, but less severe involvement of hip joints, and less severe radiographic changes. The milder course of AS in females might be one cause for the longer delay to diagnosis of the disease compared to males. These findings suggested that clinicians should be more aware of possible AS diagnosis in female patients presenting with mild or atypical AS disease symptoms.