Protective role of summer acupoint application therapy on weather-triggered rheumatoid arthritis flares

Summer acupoint application (SAA) therapy is widely practiced in China for rheumatoid arthritis (RA) prevention, but its effectiveness in mitigating weather-related RA risk remains unclear. This study evaluated the short-term association between diurnal temperature range (DTR) and RA hospitalization, and quantified SAA's protective effect using daily hospital data from Hefei, China (2013-2024; n = 9261, including 1066 SAA recipients). A time-stratified case-crossover design combined with 1:1 propensity score matching (PSM) was employed. Per interquartile range increase in DTR, cumulative RA hospitalization risk rose by 10.2% (95% CI: 2.7%-18.2%) at lag 0-7 days. After PSM, the control group exhibited elevated risk (OR = 1.138, 95% CI: 1.013-1.279), whereas the SAA group showed no significant DTR-related risk (OR = 0.889, 95% CI: 0.734-1.075), with a significant between-group difference (P = 0.030). Attributable fractions were 12.13% and - 12.54% for control and SAA groups, respectively. The protective effect of SAA therapy was stronger among females, patients aged ≥45 years, and those with more comorbidities, and was most pronounced in autumn. These findings indicate that SAA therapy may mitigate DTR-related RA hospitalization risk, highlighting a potential preventive strategy for vulnerable populations. What is innovative in this paper is that the linking of meteorological stressors with a traditional Chinese medicine (TCM) intervention was first explored, and the results of the study also showed that TCM intervention was indeed associated with a reduced risk of DTR-related RA hospitalizations. However, the observational nature of this study precludes causal inference, and future randomized controlled trials should be employed to validate these findings further.