Dr. Mease et al reply

To the Editor:

We thank Dr. Maguire et al¹ for their interest in and appreciation of our study from the Corrona Psoriatic Arthritis/Spondyloarthritis Registry comparing patient characteristics and disease burden between men and women with axial spondyloarthritis (axSpA).² Dr. Maguire and colleagues raised a number of interesting questions around the causal relationship between the higher prevalence of depression and decreased work productivity we observed in women in our study. While we were unable to directly address these questions in the Registry, we agree and appreciate that these are important research priorities for future investigations.

As we noted in our study, limited information exists on the overall disease burden of axSpA in women in the US, as women are generally underrepresented in clinical studies. Further, much of our understanding of axSpA disease burden in women is based on data from patients with ankylosing spondylitis. Our historical understanding of sex differences in axSpA is limited.³

While the higher prevalence of depression in women with axSpA may drive worse levels of function and decreased work productivity, the causal link remains unclear. Globally, more women than men perform unpaid labor,⁴ which is associated with poorer mental health.⁵ Constraints on women’s professional advancement, such as the gender wage gap, may also contribute to gendered mental health disparities.⁶ Alternatively, as Dr. Maguire and colleagues noted,¹ worse limitation in functional ability in women with axSpA may contribute to work instability and subsequent depression. Whether women with axSpA are under greater pressure to remain in the workforce remains unclear; however, a gender gap for disability benefits is well established.⁷ Women are substantially more likely to be rejected for disability insurance than men, controlling for health condition, occupation, and multiple demographic characteristics.⁸ As one of the first studies to evaluate differences in clinical and patient-reported disease burden between men and women with axSpA in the US, we hope our findings will spur additional research to further evaluate and understand these differences. We agree with Dr. Maguire and colleagues that future studies examining workforce participation and the effect of mental health in axSpA, especially in women, are paramount. One step in this direction will be gaining a deeper understanding of the influence of central sensitization, which is a broader concept than fibromyalgia and can be more prevalent in women than men.⁹ In our Registry, we have begun to assess this using the Widespread Pain Index/Symptom Severity Scale in order to determine the role of central sensitization more quantitatively on disease burden, response to treatment, comorbidities such as depression, and work productivity.

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