AB0189 CHANGING SEASONS, CHANGING JOINTS: THE INFLUENCE OF SEASONAL VARIATIONS ON PROs IN PATIENTS WITH INFLAMMATORY ARTHRITIS

Background: Inflammatory Arthritides (IA) cause complex flares, partly explained by factors like diet, lifestyle, and medications, prompting speculation about the influence of seasonality. Studies suggest that winter and spring trigger most exacerbations, but findings are contentious due to symptom overlap with Seasonal Affective Disorder (SAD). It remains unclear whether seasons directly impact disease activity or through SAD-related symptoms. Objectives: To assess the seasonal variation in PROs in patients with IA. Methods: Study data came from adults in the Forward Databank registry diagnosed with IA (RA, SLE, PsA, AS). They provided biannual questionnaires with completed Patient Activity Score-II (PAS-II) scores from 1998 to 2023. PAS-II, averaging pain VAS, patient global VAS, and HAQ-II, was the primary outcome with season as the exposure. When HAQ-II was missing, HAQ-DI substituted for PAS-II imputation. Descriptive statistics characterized patients at baseline and by season, averaging patient-reported outcomes (PROs). Gaussian GEE models, with robust standard errors, assessed PAS-II and season association. Five models adjusted for demographics, clinical variables, other PROs (fatigue, sleep), comorbidities, and treatment. The best models were selected using the QIC criteria. Results: 47,052 total participants with IA contributed 406,215 observations with mean age of 58, males 19%, and RA 84% (Table 1). Mean values of PROs over the follow-up are presented in Table 1. Higher PROs, indicating worse disease, were more frequently observed in the spring and fall. Figure 1 illustrates the five models that assess the impact of seasonal variation on PAS-II scores. The QIC scores decrease as more variables are introduced, indicating the increasing strength of the correlation structure. No difference in PAS-II is seen between winter and summer. Spring and fall have the highest coefficients in Model 1, with a PAS-II 0.13 (95% CI 0.11 – 0.14) and 0.10 (95% CI 0.09 – 0.12) higher PAS-II than in the summer. This association continues till Model 4, but in Model 5, winter, spring, and fall had the same coefficient impact on PAS-II estimates, with about a 0.04 increase in PAS2 when compared to the summer. The important factors in predicting the seasonal variation of PAS-II scores are fatigue (Z-score 149), followed by sleep (Z-score of 74.86), education (Z-score of -34.91), MCS (Z-score -32.04), RD comorbidity index (Z score 27.02), IA duration (Z-score 21.53), employment (Z-score -22.45), and prednisone use (Z score 22.7). Conclusion: We identified a seasonal correlation with PROs, impacted by factors like fatigue and sleep. Future work will explore SAD and inflammation components, using varied outcomes and consider regional weather. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: None declared.