Sex Differences in Medication Discontinuation in Axial Spondyloarthritis

Area of Science:

• Rheumatology
• Pharmacology
• Clinical Research

Background:

• Axial spondyloarthritis (axSpA) is a chronic inflammatory disease affecting the spine.
• Treatment options include tumor necrosis factor inhibitors (TNFi), interleukin-17 inhibitors (IL-17i), and Janus kinase inhibitors (JAKi).
• Understanding sex-based differences in medication adherence and discontinuation is crucial for optimizing patient care.

Purpose of the Study:

• To investigate sex differences in medication discontinuation rates among axSpA patients initiating TNFi, IL-17i, or JAKi.
• To identify potential factors influencing these sex-based disparities in treatment adherence.

Main Methods:

• Analysis of data from the Rheumatology Informatics System for Effectiveness (RISE) Registry (2003-2025).
• Assessment of medication discontinuation by sex among new users of TNFi, IL-17i, and JAKi.
• Utilized Cox regression models and Kaplan-Meier curves, adjusting for sociodemographic and clinical factors, and tested for interactions with age, race, and Area Deprivation Index (ADI).

Main Results:

• Among 7,200 axSpA patients, females showed a 24% higher risk of discontinuing TNFi and a 25% higher risk of discontinuing IL-17i compared to males.
• No significant sex differences in discontinuation were observed for JAKi users.
• Females under 65 had the lowest probability of treatment continuation with TNFi.

Conclusions:

• Females with axSpA exhibit a higher likelihood of discontinuing TNFi and IL-17i compared to males.
• The study suggests potential sex-based disparities in treatment adherence for specific axSpA medications.
• Larger studies with longer follow-up are recommended to confirm findings for JAKi discontinuation due to potential underpowering.