Sex Differences Reported in Disease Outcomes Among Patients With Axial Spondyloarthritis

Sex differences observed among patients with early axial spondyloarthritis (axSpA) are associated with disease outcomes, according to findings from a study published in Arthritis Care & Research (Hoboken).

Clinical manifestations, disease expression, treatment response, and disease progression differ between men and women with rheumatic and musculoskeletal diseases. These differences, which can be multifactorial and complex in nature, have been attributed to a variety of factors, including hormonal, genetic, psychologic, and sociocultural.

Using the longitudinal, prospective, multicenter, observational DESIR cohort study (ClinicalTrials.gov Identifier: NCT01648907), researchers evaluated differences in outcomes, such as disease activity, inflammatory markers, radiographic damage, and patient-reported outcomes (PROs), between men and women with axSpA. In addition, sex-specific factors linked to disease activity trajectories were identified.

Adult patients who presented with early inflammatory back pain (IBP) that met the Calin or the Berlin criteria were included in the analysis. Participants also had a symptom duration of greater than 3 months but less than 3 years, which was suggestive of spondyloarthritis based on evaluation by a rheumatologist.

Participants who met the Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axSpA at study entry or at any time during the follow-up were evaluated. All participants were biologic disease-modifying antirheumatic drug (bDMARD)-naive.

The main variable of interest was sex, as reported by the patient at baseline. Outcome criteria, which were collected over time and assessed based on sex, including the following:

• Ankylosing Spondylitis Disease Activity Score C-reactive protein (ASDAS-CRP),  assessed at 0, 6, 12, 18, 24, 36, 48, 60, and 72 months
• Patient Global Assessment (PGA) using the Bath Ankylosing Spondylitis Patient Global Score (BAS-G), evaluated at 0, 6, 12, 18, 24, 36, 48, 60, and 72 months
• CRP level, evaluated at 0, 6, 12, 18, 24, 36, 48, 60, and 72 months
• Radiographic sacroiliitis, according to the modified New York criteria, which were measured at baseline, 2 years, and 5 years

Other disease activity scores in the secondary analyses included Bath Ankylosing Spondylitis Disease Activity Score (BASDAI), Ritchie articular index, 28 swollen joint score, and Maastricht Ankylosing Spondylitis Enthesis score (MASES).

Physical activity and quality of life were evaluated using Health Assessment Questionnaire for axSpA (HAQ-AS), Bath Ankylosing Spondylitis Functional Index (BASFI), Ankylosing Spondylitis Quality of Life (ASQoL) Scale, and Short Form-36 (SF-36) health survey questionnaire.

Among the 708 individuals who were included in the DESIR cohort at baseline, 69.7% (n=494) who met the ASAS classification at any time point were evaluated. The mean participant age was 31.9±7.5 years and the mean disease duration was 20.7±11.7 months.

Although the mean participant age was similar between the 2 sexes at baseline, the duration of IBP was longer among women vs men. At baseline, disease activity was high and similar among both men and women (mean ASDAS-CRP score, 2.6±1.0 vs 2.6±0.9). In addition, women compared with men exhibited significantly higher ASDAS-CRP and PGA (P <.0001); however, PGA and other PROs (ie, SF-36, HAQ-AS, ASQoL, and BASFI) were worse in women than in men at baseline. Further, objective signs, such as tender and swollen joint counts and MASES enthesitis scores, were worse among women vs men at baseline. On the other hand, elevated CRP levels and sacroiliitis were significantly more common among men vs women (P <.0001).

When trajectories of disease were analyzed among men and women (n=352), 6 different trajectories were identified. In all, 38% of men and 42% of women experienced “high/very high disease” activity trajectories, and 33% of men and 34% of women experienced “high/very high disease” activity trajectories.

Although the DESIR cohort included a large sample of patients, many of them could not be evaluated because they did not satisfy the ASAS criteria for axSpA. Further, despite the fact that treatment intake over time was analyzed, the types and dosages of tumor necrosis factor (TNF) inhibitors and treatment retention were not evaluated.

“…our analysis confirms that women seem to have a different disease phenotype then men in axSpA,” the researchers noted. “Sex differences should be widely recognized and taken into account in the management of the disease. More studies are needed to determine the factors related to sex differences in the view of predicting and improving outcomes,” they concluded.

Disclosure: Some of the study authors have declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.