Comment on "Meta-analysis of meteorological conditions and rheumatoid arthritis".

This correspondence addresses critical methodological limitations in the recent meta analysis by Hu et al. regarding meteorological conditions and rheumatoid arthritis (RA). We highlight issues of clinical heterogeneity arising from the conflation of disparate outcomes and inconsistent follow-up durations. Furthermore, we identify a "quality score paradox" where small-sample studies are disproportionately rated as high-quality compared to large-scale evidence. Finally, we argue that pooling data across incompatible climatic zones neglects the effect of baseline adaptation, and we suggest that the observed association between atmospheric pressure and joint swelling supports a hydraulic physical mechanism distinct from immune-mediated inflammatory flares.