OBJECTIVETo investigate the prevalence and epidemiologic characteristics of seronegative spondyloarthritis (SpAs) in Chinese army force in different areas.

METHODS4-phase survey was conducted in 21 750 Chinese army, including: face-to-face interviews with standardized COPCORD questionnaires (Phase I screening); further examination on the suspected cases; identification of inflammatory joint and spinal diseases (Phase II); identification of SpAs (AS and uSpA) by more than two experienced specialists in rheumatology; further examination with X-rays and laboratory detection of HLA-B27 (Phase III); and data analysis (Phase IV).

RESULTSAmong 21 750 army men, 21 cases of RA, 106 cases of SpAs were identified, with prevalence rates of 0.966 per thousand, 4.87 per thousand respectively. In 106 cases of SpAs, there were 46 cases of ankylosing spondylitis (AS), 52 cases of undifferentiated SpAs (uSpAs) with the prevalence rates of 2.11 per thousand and 2.39 per thousand respectively. Few cases of reactive arthritis (ReA) and Reiter's syndrome (RS) were identified (6 and 1 cases respectively). The prevalence of AS, uSpAs were higher in navy than that in the ground force or the air force. Soldiers in cold and damp areas had higher prevalence rates than that in the plain and drought areas.

CONCLUSIONThe prevalence of SpA (especially AS and uSpA) in Chinese army force was similar to that in the civilians. SpA (AS and uSpA) was more prevalent seen in the Navy. The incidence of SpA (AS and uSpA) was influenced by environmental factors such as coldness and dampness.

Adult ; China ; epidemiology ; Humans ; Lumbar Vertebrae ; Male ; Military Personnel ; Prevalence ; Sacrum ; Spondylarthritis ; epidemiology ; etiology

BACKGROUND: The clinical features of enthesitis in patients with psoriatic arthritis (PsA) have been reported in some Western countries, but data in China are very limited. This study aimed to describe the characteristics of enthesitis in Chinese patients with PsA and compared them with those in other cohorts. METHODS: Patients with PsA enrolled in the Chinese Registry of Psoriatic Arthritis (CREPAR) (December 2018 to June 2021) were included. Data including demographics, clinical characteristics, disease activity measures, and treatment were collected at enrollment. Enthesitis was assessed by the Spondyloarthritis Research Consortium of Canada (SPARCC), Maastricht ankylosing spondylitis enthesitis score (MASES), and Leeds enthesitis index (LEI) indices. A multivariable logistic model was used to identify factors related to enthesitis. We also compared our results with those of other cohorts. RESULTS: In total, 1074 PsA patients were included, 308 (28.7%) of whom had enthesitis. The average number of enthesitis was 3.3 ± 2.8 (range: 1.0-18.0). More than half of the patients (165, 53.6%) had one or two tender entheseal sites. Patients with enthesitis had an earlier age of onset for both psoriasis and arthritis, reported a higher proportion of PsA duration over 5 years, and had a higher percentage of axial involvement and greater disease activity. Multivariable logistic regression showed that axial involvement (odds ratio [OR] 2.21, 95% confidence interval [CI], 1.59-3.08; P <0.001), psoriasis area and severity index (PASI) (OR: 1.03, 95% CI: 1.01-1.04; P = 0.002), and disease activity score 28-C reactive protein (DAS28-CRP) (OR: 1.25, 95% CI: 1.01-1.55; P = 0.037) were associated with enthesitis. Compared with the results of other studies, Chinese patients with enthesitis had a younger age, lower body mass index (BMI), a higher rate of positive human leukocyte antigen (HLA)-B27, more frequent dactylitis, and a higher proportion of conventional synthetic disease-modifying antirheumatic drugs' (csDMARDs) use. CONCLUSIONS Enthesitis is a common condition among Chinese patients with PsA. It is important to evaluate entheses in both peripheral and axial sites.
Humans ; Arthritis, Psoriatic/drug therapy* ; East Asian People ; Enthesopathy/complications* ; Registries ; Severity of Illness Index ; Spondylarthritis/epidemiology*