Does Sulfasalazine Still Have Therapeutic Value in the Treatment of Axial Spondyloarthritis? A Real‐World Cohort Study From China

OBJECTIVE: The efficacy of sulfasalazine (SSZ) in axial spondyloarthritis (ax-SpA) patients meeting both 2009 ax-SpA and 2011 peripheral SpA (p-SpA) criteria is unclear. This study aimed to assess SSZ's clinical efficacy in pure ax-SpA and overlapping ax-SpA patients and to identify factors influencing peripheral symptom development. METHODS: SpA patients from 2016 to 2023 at the First Medical Center of People's Liberation Army General Hospital were categorized into pure ax-SpA and ax-SpA with peripheral features. They received nonsteroidal anti-inflammatory drugs (NSAIDs) alone or with SSZ. The study evaluated SSZ's efficacy, peripheral symptom timing and prevalence, and factors affecting symptom onset using Cox regression. RESULTS: Of 670 SpA patients, 469 maintained pure axial involvement throughout follow-up, while 201 developed peripheral symptoms during follow-up. had pure ax-SpA. The SSZ plus NSAIDs group demonstrated significantly lower Axial Spondyloarthritis Disease Activity Score than NSAIDs-only in both pure axial (1.2 vs. 1.8; p = 0.015) and axial-with-peripheral subgroups (1.1 vs. 1.8; p = 0.011). New peripheral symptoms occurred in 33.2% of the NSAIDs group and 15.1% of the SSZ plus NSAIDs group. SSZ reduced the risk of peripheral symptom development (hazard ratio [HR] = 0.489, p = 0.0028). In the Cox proportional hazards model adjusted for age, sex, smoking status, body mass index, and Human Leukocyte Antigen B27 status, male gender (HR = 0.64, p = 0.020) and SSZ use (HR = 0.47, p = 0.004) emerged as protective factors, whereas smoking significantly increased risk (HR = 1.97, p < 0.001). CONCLUSIONS: SSZ reduces disease activity, improves quality of life among ax-SpA patients, reduces the incidence of peripheral symptoms, and delays their onset. About one-third of ax-SpA patients develop peripheral symptoms over time, which are associated with poorer functional status and quality of life. Smoking increases this risk, while male gender and SSZ use offer protection.