During a median follow-up time of 5.6 years, the incidence of RA was 187.4 and 135.2 per 100,000 person-years in AGI users and TZD users, respectively. TZD use was associated with a reduction in RA incidence, with a hazard ratio of 0.72 (95% CI, 0.59–0.89). Various subgroup analyses and sensitivity analyses were consistent with the results of the primary analysis.4
Implications for Clinical Practice
Houyu Zhao, PhD, Xiaowei Chen, BS, and Siyan Zhan, PhD, Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China, were kind enough to share their take on the clinical implications of their fascinating research.
The Rheumatologist (TR): What can practicing rheumatologists take away from your findings?
Zhao et al.: Our study demonstrated that use of TZDs was associated with a lower incidence of RA in the Chinese population with type 2 DM, and had a greater protective effect on RA in female patients. Our findings could provide some evidence for the clinical application of glucose-lowering agents in the prevention of RA among patients with type 2 DM, as well as for the issue of drug safety in TZD. Rheumatologists could collaborate with endocrinologists or primary care physicians to optimize diabetes management strategies in patients with concurrent RA risk factors, taking into account the potential impact of TZD therapy on RA prevention. However, our results have not been confirmed by randomized clinical trials yet. More studies are needed before our results can be applied to clinical practice.
TR: What can’t this study tell us?
Zhao et al.: The study’s observational design, even with robust statistical adjustments, cannot establish causality. While it suggests an association between TZD use and reduced RA incidence, it cannot definitively prove that TZDs directly prevent the development of RA, so the results of this study cannot directly guide [clinical practice]. Moreover, the enrolled patients were from a single municipal district in China, so the conclusions of the study should not be generalized to other ethnic populations without caution. Despite efforts to adjust for potential confounders using statistical methods, other confounding factors, such as lifestyle factors (e.g., dietary habits) were not considered, [and these] have been shown to be associated with the risk of RA. Finally, the study’s follow-up period may not capture long-term outcomes, such as delayed onset of RA or potential adverse effects of prolonged TZD use.
TR: What would be your next steps in terms of future research?
