Background: Patients with Juvenile idiopathic arthritis (JIA) suffer considerable morbidity due to articular and extra-articular manifestations, including ocular, non-articular musculoskeletal, endocrine, cutaneous sequelae, and secondary amyloidosis, which can lead to serious impairment of their physical function and health-related quality of life [1]. To date, little is known about the prevalence and incidence rate of comorbidities in long term JIA.

Objectives: To assess the prevalence and incidence rates of key comorbidities in JIA patients reaching adulthood and its possible association with specific demographic and clinical characteristics.

Methods: This is a national multicentric retrospective observational cohort study. Data on sociodemographic, clinical features and comorbidities were collected from patients with JIA according to the 2001 revised International League of Associations for Rheumatology (ILAR) criteria, registered in the Rheumatic Diseases Portuguese Register (Reuma.pt), who were at least 18 years old at the time of data extraction. Comorbidities included cardiovascular disease, arterial hypertension, dyslipidaemia, diabetes, thyroid disease, amyloidosis, inflammatory bowel disease, allergy and asthma, osteoporosis, psychiatric disease, and autoimmune disease. Due to small frequencies of some comorbidities these were clustered into wider groups, namely cardiovascular disease, which included ischemic heart disease, cardiac failure, arrhythmia, pericarditis, peripheral arterial disease, ischemic stroke, and valvular disease; as well as autoimmune disease, which included type 1 diabetes mellitus, Graves and Hashimoto’s thyroiditis, vitiligo, myasthenia gravis, multiple sclerosis, coeliac disease, and autoimmune hepatitis. We did not consider extra-articular manifestations of JIA, such as psoriasis or uveitis. Incidence rates of comorbidities were calculated as the number of new events per 1000 person-years with 95% CI and prevalence was defined using frequencies.

Results: This study included 924 patients, of which 557 (60.3%) were female with a median [IQR] age of 29.7 [21.2] years. Median age at disease onset was 11.5 [7.8] years, median disease duration was 20.6 [19.7] years and median diagnostic delay was 1.0 [4.7] year. The most frequent category of JIA was undifferentiated JIA (n=293, 31.7%), followed by rheumatoid factor-negative polyarticular JIA (n=191, 20.7%). Most patients were prescribed conventional synthetic DMARDs (csDMARDs; 668, 72.2%) and biologic DMARDs (bDMARDs; 504, 54.7%). The comorbidities with the highest incidence rate were autoimmune diseases (6.3/1000 person-years), followed by arterial hypertension (6.1/1000 person-years) and dyslipidaemia (4.6/1000 person-years). The incidence of malignancy was 0.6/1000 person-years. The most prevalent comorbidities were hypertension (n=95, 10%), psychiatric disease (n=60, 6%) and osteoporosis (n=54, 5.6%). Biologic DMARD therapy in these patients was associated with a decreased risk of developing cardiovascular disease (OR 0.48, p=0.03), arterial hypertension (OR 0.39, p<0.001), dyslipidaemia (OR 0.49, p=0.01), thyroid disease (OR 0.16, p=0.01), amyloidosis (OR 0.12, p=0.049), anaemia (OR 0.21, p=0.02), inflammatory bowel disease (OR 0.31, p<0.001), autoimmune diseases (OR 0.13, p<0.001, osteoporosis (OR 0.39, p=0.003), psychiatric disease (OR 0.3, p<0.001), asthma and allergy (OR 0.19, p<0.001). No significant association between therapy with bDMARDs and development of malignancy or infections was found.

Conclusion: JIA patients commonly experience comorbidities in the long term, with hypertension being the most frequent. Biologic DMARD treatment seems to be associated with a decreased risk of developing comorbidities. These findings underscore the importance of careful management and monitoring of comorbidities in JIA patients.

REFERENCES: [1] Ramos FO, Rodrigues A, Martins FM, Melo AT, Aguiar F, Brites L, et al. Health-related quality of life and disability in adults with juvenile idiopathic arthritis: comparison with adult-onset rheumatic diseases. RMD open. 2021;7(3):e001766.

Acknowledgements: NIL.

Disclosure of Interests: None declared.

© The Authors 2025. This abstract is an open access article published in Annals of Rheumatic Diseases under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ ). Neither EULAR nor the publisher make any representation as to the accuracy of the content. The authors are solely responsible for the content in their abstract including accuracy of the facts, statements, results, conclusion, citing resources etc.