Abstract: Rheumatic diseases prevalence and characteristics in Mexico may vary depending on the country´s region 1 . To acknowledge these differences is needed to develop focused strategies for early diagnosis and treatment 2 . Objectives Identify the sociodemographic, clinical and treatment characteristics of the rheumatic diseases in the different regions in Mexico using data from the Mexican Adverse Events Registry (BIOBADAMEX). Methods In this analysis we included all patients registered from 2016 to 2021. We described the prevalence in the northern region of Mexico (NR), central (CR) and southern region (SR). We compared sociodemographic, clinical and treatment characteristics between these three regions. We used descriptive statistics, Chi square and Kruskal Wallis tests to analyze differences between the groups. Results A total of 780 patients were included in this study, 248 patients (32%) were from the NR, 471 (60%) were from the CR and 61 (8%) from the SR. At baseline, patients had a median (IQR) age of 50 (40-58) years and median disease duration of 7 (3-15) years. NR patients had longer disease duration (9.7 years, p 〈 0.001) and SR patients had higher BMI (29, p 0.001). Overall, 351 (45%) had comorbidities. In CR and SR more than the half of the patient had comorbidities, while in NR only 29% (p 0.001). The most common diagnosis was rheumatoid arthritis with 512 (66%) patients, followed by ankylosing spondylitis in 115 (15%), psoriatic arthritis in 44 (6%), systemic lupus erythematosus in 30 (4%) and idiopathic juvenile arthritis in 27 (3%), this proportions were maintained when analyzed by regions. We found SR had higher DAS 28 and higher BASDAI (Table 1). Table 1. Baseline characteristics by region. Northern regionn=248 Central regionn=471 Southern regionn=61 p Age, median(IQR) 49.7 (42-58) 49.9 (38-58) 51.6 (43-61) 0.4 Female, n(%) 193 (78) 383 (81) 52 (85) 0.33 Body Mass Index, median (IQR) 28 (25-32) 26 (22-29) 29 (26-32 ) 0.001 Disease duration (years), median (RIC) 9.7 (5-16 ) 5.9 (2-14) 4.5 (1-10) 0.001 Diagnostic, n(%):  Rheumatoid arthritis 173 (70 ) 300 (64) 39 (64) 0.001  Idiopathic Juvenile Arthritis 3 (1) 23 (5 ) 1 (2)  Ankylosing Spondylitis 47 (19 ) 59 (13) 9 (15) Laboratory studies, n(% ) Rheumatoid factor 97 (39) 274 (58) 38 (62 ) 0.001 ACPA 15 (6) 68 (14) 12 (19 ) 0.001 Disease activity scores, median (IQR )  DAS28 4.8 (3-6) 5.1 (4-6) 5.2 (5-7 ) 0.001  BASDAI 2.8 (0-7) 4.9 (2-7) 8.0 (5-9 ) 0.003 Comorbidities, n(% ) 72 (29) 247 (52 ) 32 (52 ) 0.001 Previous bDMARD, n(%): 136 (55 ) 149 (32) 1 (2) 0.001 Steroids, n(%): 93 (38) 155 (33) 42 (69 ) 0.001 cDMARD, n(% ) 200 (81) 373 (79) 53 (87) 0.4 Cause of bDMARD discontinuation, n(% ) a Lack of efficacy 85 (62 ) 45 (33) 2 (22) 0.001 Adverse Event 4 (3) 25 (18) 3 (33 ) Pregnancy 1 (1) 3 (2 ) 0(0) Loss of patient follow up 10 (7) 0 (0) 2 (22 ) Remission 23 (17 ) 5 (4) 0 (0) Others 14 (10) 59 (43 ) 2(22) a) 238 patients. Glucocorticoids were used by 290 (37%) patients, SR had the highest use rate (69%, p 〈 0.001) and 80% of the patients used conventional DMARDs (cDMARDs) with no differences between regions. Overall, the most used bDMARDs were adalimumab, certolizumab, tocilizumab and abatacept. At the time of the analysis 238 (36%) had discontinued bDMARDs treatment, 132 (47%) due to lack of response, being this the most frequent cause reported overall, with the highest rate in NR (62%, p 〈 0.001). All NR patients have social security compared to 83% in CR and 79% in SR. Conclusion There are regional differences between patients with rheumatic diseases registered in Biobadamex. It was remarkable that all patients form NR had social security, which may impact in the access to treatment. There were differences in the treatments between regions. The data from this analysis may be useful to policy makers, pharmaceutical companies and physicians. Differences in size samples between regions could have influenced in the results, further analyses will be performed in the future including more patients. References [1]Peláez-Ballestas I et al. J Rheumatol 2011;86;3-8. [2]Chopra A et al. Best Pract Res Clin Rheumatol 2008;22:583-604. Disclosure of Interests VIJAYA RIVERA TERAN: None declared, David Vega-Morales: None declared, Sandra Sicsik: None declared, Fedra Irazoque-Palazuelos: None declared, Miguel A Saavedra: None declared, Julio Cesar Casasola: None declared, Sandra Carrilo: None declared, Angélica Peña: None declared, Angel Castillo Ortiz: None declared, Omar Eloy Muñoz-Monroy: None declared, Sergio Duran Barragan: None declared, Azucena Ramos: None declared, Luis Francisco Valdés Corona: None declared, Estefanía Torres Valdéz: None declared, Aleni Paz: None declared, ERICK ADRIAN ZAMORA-TEHOZOL: None declared, Alfonso Torres: None declared, Samara Mendieta: None declared, Daniel Xavier Xibille Friedmann: None declared, Francisco Guerrero: None declared, Natalia Santana: None declared, Miguel Vazquez: None declared, Claudia Zepeda: None declared, Melanea Rivera: None declared, Kitzia Alvarado: None declared, Deshire Alpizar-Rodriguez Consultant of: Scientific advisor for GSK, unrelated to this study., Employee of: Scientific advisor for GSK, unrelated to this study.