Can Tumor Necrosis Factor Inhibitors Reduce the Risk of Fractures in AS Patients?

To explore trends in fracture risk among individuals with ankylosing spondylitis (AS), researchers examined how introducing tumor necrosis factor inhibitors (TNFi) may influence fracture rates since these TNFi drugs are believed to mitigate inflammation, which may lower the fracture risk. The researchers utilized the National Veterans Affairs database to compile data between 2000 and 2002 (before TNFi treatment) and between 2004 and 2020 (during/after TNFi treatment) to identify adults diagnosed with AS and determine how receiving disease-modifying antirheumatic drugs impacts fracture risk for their study published in Arthritis Care and Research.

The study focused on calculated and standardized fracture incidence rates, and researchers also conducted an interrupted time series analysis to compare fracture rates before and after the introduction of TNFi drugs. The study involved 3794 patients with AS, with a mean age of 53 years and a predominance of male participants. There were 1152805 comparators without AS, with a mean age of 60 years included in this study. Over the study period, the fracture incidence rate increased for individuals with AS and non-AS participants. For AS, the incidence rate increased from 7.9/1,000 person-years in 2000 to 21.6/1,000 person-years in 2020. There was also an increase in fracture rates among comparators. Thus, the ratio of fracture rates between the two groups remained relatively constant.

The introduction of TNFi drugs in the year 2003 did not lead to a significant reduction in fracture rates for individuals with AS. This finding suggests that despite the potential anti-inflammatory effects of TNFi drugs, they did not substantially impact fracture risk in this population.

The study revealed that fracture rates have risen over time in individuals with AS and those in the general population. Despite introducing TNFis as a potential mechanism to alleviate inflammation and lower fracture risk, the study did not find a significant reduction in fracture rates among those with AS.

Reference

Sali Merjanah, Liew JW, Bihn J, et al. Trends in fracture rates over two decades among veterans with ankylosing spondylitis. Arthritis Care and Research. Published online June 12, 2023. doi:10.1002/acr.25166