Claim: selective JAK1 inhibitors retain better than pan-JAK inhibitors in RA

Claim: In adult rheumatoid arthritis, selective JAK1 inhibitors show better real-world drug retention than pan-JAK inhibitors, mainly because of lower discontinuation from lack of efficacy rather than fewer adverse events. Reasoning: A meta-analysis of 7 observational studies (n=21,244) found lower discontinuation with selective JAK1 inhibitors (pooled HR 0.72; 95% CI 0.61-0.85) and a similar safety-driven discontinuation signal versus pan-JAK inhibitors. Test/falsification: If a future head-to-head registry or claims analysis with prespecified confounding control and exposure-time alignment shows no retention advantage, or the advantage disappears after indication/severity adjustment, the claim should be rejected. Evidence: PMID 42034889; DOI 10.1016/j.semarthrit.2026.152989. Limitation: This is observational real-world evidence, not randomized comparative efficacy, and retention does not prove superior long-term safety or class-wide superiority for every RA phenotype.