US Observational Data Show Variable Real-World Outcomes With JAK Inhibitors in RA
Key Takeaways
- A study reviewing 35 US observational studies evaluated real-world effectiveness of Janus kinase inhibitors (JAKi) for rheumatoid arthritis (RA).
- Adherence and persistence varied, with proportion of days covered ranging from 0.53 to 0.83 and median persistence from 121 to 516 days.
- Clinical and patient-reported outcomes showed modest improvement, supporting real-world effectiveness outside randomized trials.
Real-world evidence (RWE) is increasingly used to complement randomized controlled trial data in rheumatoid arthritis treatment decision-making. A new study synthesized observational studies evaluating the real-world effectiveness of Janus kinase inhibitors in US patients with RA, focusing on treatment patterns, clinical outcomes, and patient-reported outcomes across routine clinical settings.
Study Findings
The study followed PRISMA guidelines and included 35 US-based observational studies published through June 2, 2023. Patient sample sizes ranged from 252 to 30 556, reflecting diverse real-world populations. Most studies relied on administrative claims databases (65.7%), with the remainder using electronic medical records (EMRs) or patient registries.
Treatment adherence was reported in 11 claims-based studies, with proportion of days covered ranging from 0.53 to 0.83. Persistence was assessed in 14 studies, with median time on therapy without discontinuation spanning 121 to 516 days. Reported discontinuation rates ranged from 11% to 72.4%, reflecting variation in study design and persistence definitions.
Six studies applied claims-based effectiveness algorithms incorporating adherence, treatment stability, and glucocorticoid use. Using these criteria, 14.8% to 26% of patients met definitions for effective treatment.
Clinical effectiveness was most commonly assessed using the Clinical Disease Activity Index (CDAI). Ten studies reported mean CDAI changes, generally at 6 months, ranging from −4.7 to 5.1. Other clinical outcomes included DAS28 scores, ACR response criteria, and joint counts.
Patient-reported outcomes were evaluated in 12 studies, primarily using registry data. Pain was the most frequently assessed outcome, with mean changes ranging from −9.3 to 8.9. Additional measures included fatigue, morning stiffness, HAQ-DI, and RAPID3, although reporting was inconsistent across studies.
Overall study quality was assessed using the Newcastle-Ottawa Scale, with most studies rated as high quality.
Clinical Implications
These findings provide important context for clinicians and payers evaluating JAK inhibitors in routine RA management. While randomized trials demonstrate efficacy under controlled conditions, this review highlights variability in real-world adherence, persistence, and clinical response.
Claims-based analyses offer insight into medication use patterns relevant to managed care, though they lack detailed clinical granularity. Registry and EMR data help address this gap by capturing disease activity and patient-reported outcomes, which are increasingly emphasized in value-based care.
The modest improvements observed in disease activity and pain underscore the importance of setting realistic expectations for treatment outcomes in real-world populations. For managed care stakeholders, these data may inform formulary decisions, utilization management strategies, and patient selection for JAK inhibitor therapy.
Conclusion
This study demonstrates that JAK inhibitors provide measurable real-world benefits for US patients with rheumatoid arthritis, with moderate adherence, sustained persistence, and modest improvements in clinical and patient-reported outcomes. The findings complement randomized trial data and support the role of real-world evidence in informing managed care and clinical decision-making.
Reference
Gandy C, Bazzazzadehgan S, Bruera S, Huang Y. Evaluation of real-world evidence to assess effectiveness outcomes of Janus kinase inhibitors for rheumatoid arthritis: a systematic review of US studies. Drug Healthc Patient Saf. 2025 Jan 7;17:25-49. doi:10.2147/DHPS.S492887.
