Background/Purpose:   The aim of this study was to set up a large, longitudinal and prospective database to investigate the epidemiology, pathogenesis, diagnosis, and prognosis of ankylosing spondylitis (AS) through mobile health in the Chinese population.

Methods:   449 consecutive outpatients with confirmed AS or spondyloarthritis (SpA) were recruited and followed annually with Smart Management System for SpA (SMSP). Characteristics of registration and demography (age, gender, time of back pain onset, diagnosis, presence of AS-related clinical manifestations, family history) and the current condition (disease activity, severity, treatments, laboratory tests) were collected online with SMSP.

Results:   449 patients (mean age: 29.4±8.5 years, male 84.0 %, HLA-B27 positive rate 81.2%) were included in the analysis. In this cross-sectional analysis, only data at the first visit were used (from May 2014 to December 2014). A history or current symptoms suggestive of peripheral arthritis, enthesitis, acute anterior uveitis, psoriasis and inflammatory bowel disease were observed in 46.4%, 69.1%, 10.5%, 2.4% and 5.8% of the patients, respectively. Differences in symptom duration (≤ 5 years, 5 years to 10 years and > 10 years) were analyzed. The 3 groups did not differ in the frequency of gender, HLA-B27 positivity, family history, arthritis, enthesitis, inflammatory bowel disease, psoriasis, and abnormal CRP. Pain located in thoracic spine (34.1%), anterior chest wall pain (28.1%) and uveitis (18.5%) were detected significantly more frequently in patients with symptom duration of > 10 years.

The association of clinical variables and laboratory markers with patient’s poor physical mobility (lumbar flexion Impairment, cervical flexion Impairment and chest activity limitation) was evaluated with multivariate logistic regression model. The result revealed that 121 patients (26.9 %) had reduced lumbar mobility; 93 patients (20.7 %) had impaired cervical flexion and 104 patients (23.2 %) had reduced chest expansion. The analyses showed that symptom duration is independently associated with poor physical mobility of any of the body parts mentioned above (OR = 1.11, OR = 1.14, OR = 1.13, respectively). Age at onset is only significantly associated with chest expansion limitation (OR = 1.06). Cervical spine pain at onset is determined to be closely related to cervical flexion impairment (OR = 1.98). Also, smokers and ASDAS are determined to have an unfavorable effect upon outcomes of cervical flexion (OR=2.06, OR = 1.38, respectively). Smokers, abnormal CRP, and ASDAS correlate with a poor prognosis in lumbar flexion (OR = 2.44, OR = 2.05, OR =1.45, respectively).

Conclusion:   This is the first prospective cohort study of ankylosing spondylitis and the first smart management system for SpA in China. With increasing global popularity of smart phone technology, there is a great opportunity for using mobile phone applications for disease management. This large cohort may improve our knowledge on the characteristics, pathogenesis and natural course in Chinese patients with AS.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/a-prospective-study-of-ankylosing-spondylitis-in-china-with-smart-management-system-for-spondyloarthritis-study-design-and-baseline-characteristics-of-the-449-recruited-patients/