Comparison of clinical characteristics between adult-onset and juvenile-onset non-radiographic axial spondyloarthritis in Chinese patients: results from the COCAS cohort.

BACKGROUND: Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease predominantly affecting the axial skeleton. We aimed to describe the clinical characteristics of patients with non-radiographic axSpA (nr-axSpA) in China and compare the differences between adult- and juvenile-onset cases. METHODS: A cross-sectional study was conducted using data from 776 patients with nr-axSpA in the Clinical Characteristic and Outcome in Chinese Axial Spondyloarthritis (COCAS) study cohort. Patients were divided into two groups including the adult-onset group (n = 662) and the juvenile-onset group (n = 114) according to age at disease onset. Baseline demographics and clinical characteristics were compared between patients with adult-onset and juvenile-onset nr-axSpA. RESULTS: Overall, the male-to-female ratio was 1.26:1, the prevalence of HLA-B27 positivity was 72.2%, and the median age at disease onset of nr-axSpA was 22 years. Nearly 75% of nr-axSpA patients had peripheral arthritis in the disease course, and the prevalence of extra-articular manifestations was 10.4%. The juvenile-onset group contained a higher proportion of men (66.7% vs. 53.9%, P = 0.011) and a longer baseline disease duration (4.0 [4.0] vs. 1.6 [3.5], P < 0.001) than the adult-onset group. A family history of spondyloarthritis was more frequent in the juvenile-onset group than in the adult-onset group (23.7% vs. 15.4%, P = 0.028), but no significant difference in the prevalence of HLA-B27 positivity was observed between the two groups (P = 0.537). Regarding initial symptoms, peripheral arthritis occurred more often in patients with juvenile-onset nr-axSpA, whereas patients with adult-onset nr-axSpA presented more frequently with axial involvement. The prevalence of inflammatory back pain (IBP) was higher in the adult-onset group than in the juvenile-onset group (85.0% vs. 75.4%, P = 0.010), whereas the juvenile-onset group showed a higher prevalence of peripheral arthritis and enthesitis than the adult-onset group (67.5% vs. 48.5%, P < 0.001; 35.1% vs. 23.3%, P = 0.007, respectively). CONCLUSIONS: Compared with adult-onset nr-axSpA, juvenile-onset nr-axSpA was more common in men and those with a family history of spondyloarthritis. Juvenile-onset nr-axSpA presents with a "peripheral predominant" mode at disease onset and a higher frequency of peripheral arthritis and enthesitis during the disease course.

Risk factors for progression of juvenile-onset non-radiographic axial spondyloarthritis to juvenile-onset ankylosing spondylitis: a nested case-control study.

OBJECTIVE: To evaluate the clinical characteristics of juvenile-onset non-radiographic axial spondyloarthritis (nr-axSpA) and to investigate risk factors associated with progression to juvenile-onset ankylosing spondylitis (JoAS). METHODS: A nested case-control study was conducted using the retrospectively collected data of 106 patients with juvenile-onset nr-axSpA (age at disease onset, <16 years) in the Clinical characteristic and Outcome in Chinese Axial Spondyloarthritis study cohort. Baseline demographic and clinical characteristics and prognosis were reviewed. Logistic regression analyses were performed to investigate risk factors associated with progression to JoAS. RESULTS: Overall, 58.5% of patients with juvenile-onset nr-axSpA presented with peripheral symptoms at disease onset. In 82.1% of these patients, axial with peripheral involvement occurred during the disease course. The rate of disease onset at >12 years and disease duration of ≤10 years were significantly higher in those with progression to JoAS than in those without progression to JoAS (83.0% vs 52.8%, p=0.001; 92.5% vs 56.6%, p<0.001, respectively). Multivariable logistic regression analysis revealed that inflammatory back pain (IBP) (OR 13.359 (95% CI 2.549 to 70.013)), buttock pain (OR 10.171 (95% CI 2.197 to 47.085)), enthesitis (OR 7.113 (95% CI 1.670 to 30.305)), elevated baseline C reactive protein (CRP) levels (OR 7.295 (95% CI 1.984 to 26.820)) and sacroiliac joint-MRI (SIJ-MRI) positivity (OR 53.821 (95% CI 9.705 to 298.475)) were significantly associated with progression to JoAS. CONCLUSION: Peripheral involvement was prevalent in juvenile-onset nr-axSpA. IBP, buttock pain, enthesitis, elevated baseline CRP levels and SIJ-MRI positivity in patients with the disease are associated with higher risk of progression to JoAS.

Rapid Onset of Efficacy of Baricitinib in Chinese Patients with Moderate to Severe Rheumatoid Arthritis: Results from Study RA-BALANCE.

INTRODUCTION: Baricitinib is an oral, selective inhibitor of Janus kinase which demonstrates clinical efficacy in patients with rheumatoid arthritis (RA). This report aims to analyze the onset time of baricitinib in Chinese patients with moderately to severely active RA who had an inadequate response to methotrexate. METHODS: This post hoc analysis evaluated clinical improvements of Chinese patients treated with baricitinib 4 mg once daily compared with placebo, based on data from a phase 3 study RA-BALANCE. Efficacy measures including American College of Rheumatology 20% (ACR20) response, ACR core set values, Disease Activity Score modified to include the 28 diarthrodial joint count (DAS28) using high-sensitivity C-reactive protein (hsCRP), DAS28-erythrocyte sedimentation rate, Simplified Disease Activity Index, Clinical Disease Activity Index, DAS28-hsCRP ≤ 3.2 response (low disease activity), and Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) were evaluated at weeks 1, 2, 4, 8, 12, 14, 16, 20, and 24 (except for FACIT-F evaluated every 4 weeks). A logistic regression model and an analysis of covariance model were used to analyze treatment comparisons of categorical and continuous measures, respectively. RESULTS: Statistically significant (p ≤ 0.05) improvements were observed as early as week 1 or 2 for the baricitinib group compared to placebo in almost all main efficacy measures. For other outcomes including 66 swollen joint count, 68 tender joint count, FACIT-F, and DAS28-hsCRP ≤ 3.2 response rate, differences were evident (p ≤ 0.05) by week 4 in the baricitinib group compared with placebo. Significant improvements in all efficacy measures were sustained through 24 weeks. CONCLUSIONS: Baricitinib demonstrated a rapid onset of efficacy on ACR20 response, ACR core set values, disease activity, and patient-reported outcome improvements in Chinese patients from RA-BALANCE. TRIAL REGISTRATION: ClinicalTrials.gov identifier, NCT02265705.

Pannus inflammation in sacroiliitis following immune pathological injury and radiological structural damage: a study of 193 patients with spondyloarthritis.

BACKGROUND: The pathogenesis of sacroiliitis is unclear; therefore, we aimed to systematically study the immunopathology of sacroiliitis in patients with axial spondyloarthritis (axSpA), and explore the relationship between pannus formation, inflammation, and the structural damage caused by sacroiliitis. METHODS: Fine needle aspiration biopsy of the sacroiliac joint (SIJ) was performed in 193 patients with axSpA. Clinical, laboratory, and imaging data were collected at baseline and during the follow up. Immunohistochemistry analysis was performed to detect CD34+ microvessels, CD68+ osteoclasts/macrophages, vascular endothelial growth factor (VEGF), metalloproteinase-3 (MMP-3), tumor necrosis factor-α (TNF-α), and caspase-3. Autopsy subjects were used as controls. RESULTS: In early sacroiliitis (grade 0-1) all pathological features could be observed, with the most common being subchondral pannus formation. Among the 193 patients, 98 were followed up for 1-13 years (mean 3.6 years); 63.3% had radiological progression at the endpoint. Multiple regression analysis showed that cartilage pannus invasion (OR 2.99, P = 0.010) and endochondral ossification (OR 3.97, P = 0.049) at baseline were risk factors for radiological structural damage. Compared to SIJ controls, the subchondral microvessel density, number of CD68+ multinuclear osteoclasts, and the levels of VEGF, caspase-3, MMP-3, and TNF-α expressed at the interface of the bone and cartilage were significantly higher in patients with sacroiliitis. CONCLUSIONS: Subchondral fibrovascular tissue formation is the most important pathological feature in early sacroiliitis. The existence of cartilage pannus invasion or endochondral ossification at baseline can predict radiological structural damage during the follow up.

A long-term, observational cohort study on the safety of low-dose glucocorticoids in ankylosing spondylitis: adverse events and effects on bone mineral density, blood lipid and glucose levels and body mass index.

OBJECTIVES: This study aimed to investigate the risk of adverse events and effects on bone mineral density (BMD), blood lipid and glucose levels and body mass index (BMI) of low-dose glucocorticoid (GC) treatment in ankylosing spondylitis. DESIGN: We performed a retrospective, observational cohort study. Adverse effects were compared between GC users and non-GC users, and we analysed differences in the duration of GC exposure (no GC exposure, <6 months, 6 months to 2 years and >2 years). SETTING: Outpatient clinic in a tertiary general hospital in China, rheumatology follow-up visits over the past 30 years. PARTICIPANTS: We included 830 patients with ankylosing spondylitis who were followed up for at least 6 months without a previous history or current complications of active gastrointestinal problems, hypertension, psychiatric or mental problems, diabetes mellitus, tuberculosis and hepatitis. The median follow-up time was 1.6 years (range 0.5-15 years, a total of 1801 patient-years). RESULTS: A total of 555 (66.9%) patients were treated with low-dose GCs, and the median cumulative duration of GC therapy was 1.3 years (range 0.1-8.5 years). Dermatological incidents, including acne, bruisability and cutaneous infections, were the most common adverse events, with a cumulative incidence rate of 5.4% (22.2 events per 1000 patient-years), followed by a puffy and rounded face (1.6%), symptoms of weight gain (1.1%) and serious infections (1.0%). The rates of all other types of adverse events were less than 1%. The GC groups (GC users and non-GC users) and the duration of GC therapy were not associated with the frequency of low BMD, dyslipidaemia, hyperglycaemia or obesity (p<0.05). CONCLUSIONS: Adverse events during long-term treatment of low-dose GCs are limited. Low-dose GCs do not have an adverse effect on BMD, blood lipid and glucose levels and BMI.

Prevalence and risk factors of osteoporosis in patients with ankylosing spondylitis: a 5-year follow-up study of 504 cases.

OBJECTIVES: The objective of this study was to assess the prevalence and risk factors of osteoporosis (OP) in patients with ankylosing spondylitis (AS). METHODS: Demographic and clinical data of 504 AS patients were collected. Bone mineral density (BMD) measurements of the lumbar spine, proximal femur and forearm were performed by dual-energy x-ray absorptiometry at baseline and follow-up. 106 cases of sex- and age-matched healthy volunteers were enrolled as normal controls. RESULTS: In contrast to normal controls, AS patients displayed a higher prevalence of both OP (9.7% vs. 0%) and osteopenia (57.5% vs. 34.9%). The prevalence of OP was significantly higher and the BMD were significantly lower in patients with elevated erythrocyte sedimentation rate (ESR) or C-reactive protein (CRP) than patients with normal ESR and CRP. Juvenile onset, morning stiffness lasting over 0.5 hours and elevated ESR levels were risk factors for bone loss at the lumbar spine; Male gender, older age, hip involvement and lack of regular treatment were risk factors for bone loss at the femur. 173 cases were followed up for 1 to 5 years, BMD changes per year at the lumbar spine, femur and forearm were 4.8%, 2.7%, and 2.6% respectively. There was no significant difference in annual BMD change between patients treated with or without low dose glucocorticoids (GCs). Hip involvement and persistent elevated ESR levels, but not GCs treatment, were associated with decreased BMD at both the lumbar spine and the femur during follow-up in longitudinal regression analysis. CONCLUSIONS: High disease activity and hip involvement are risk factors of bone loss in patients with AS. Low-dose GCs treatment in AS does not increase the risk of OP.

Arylamine N-acetyltransferase polymorphisms in Han Chinese patients with ankylosing spondylitis and their correlation to the adverse drug reactions to sulfasalazine.

BACKGROUND: Polymorphisms of Arylamine N-acetyltransferase (NAT) that contribute to diverse susceptibilities of some autoimmune diseases are also linked to the metabolism of several drugs including sulfasalazine (SSZ). The aim of this study was to investigate the distribution of NAT polymorphisms in Han Chinese patients with ankylosing spondylitis (AS) and their correlation to sulfasalazine-induced adverse drug reactions (ADRs). METHODS: Arylamine N-acetyltransferase 1 (NAT1) and arylamine N-acetyltransferase 2 (NAT2) genotypes were determined in 266 AS patients who received SSZ treatment and 280 healthy controls. The correlation between NAT polymorphisms and SSZ-induced ADRs was analyzed. RESULTS: The co-occurrence frequency of NAT2 fast acetylator genotype and NAT1*10/NAT1*10 genotype was lower in AS patients than in controls. No positive correlations were detected between NAT polymorphisms and AS clinical features. The prevalence of SSZ-induced ADRs and drug withdrawal was 9.4% and 7.1%, respectively. The frequencies of overall ADRs, dose-related ADRs, and termination of drug treatment because of intolerance were higher in the NAT2 slow acetylator genotype carriers than in the fast-type carriers and in those with co-existence of NAT1 and NAT2 slow acetylator genotypes. Furthermore, the ADRs emerged earlier in the AS cases carrying both NAT1 and NAT2 slow acetylator genotypes. CONCLUSIONS: The prevalence of co-occurring NAT2 fast acetylator genotype and NAT1*10/NAT1*10 genotype was lower in AS patients than in controls. The NAT2 slow acetylator genotype and co-existing NAT1 and NAT2 slow acetylator genotypes appear to be associated with higher risks of SSZ-induced ADRs.

Ten years' experience with needle biopsy in the early diagnosis of sacroiliitis.

OBJECTIVE: To evaluate the usefulness of needle biopsy in the diagnosis of early sacroiliitis to improve the diagnostic level and outcome of ankylosing spondylitis (AS). METHODS: One hundred nine patients in whom early AS was highly suspected, but in whom only sacroiliitis of grade I or lower on radiography/computed tomography (CT) was seen, were recruited for study. CT-guided needle biopsy of the sacroiliac joints was performed, and the patients were followed up for 5-10 years. RESULTS: Of the 109 patients, magnetic resonance imaging (MRI) was used to confirm the presence or absence of sacroiliitis in 77 patients. Of these, 23 patients were determined to have sacroiliitis on MRI, and 54 had no sacroiliitis on MRI. Needle biopsy was performed on all 109 patients. Features of inflammation were found in 85 patients, which included all 23 patients with MRI evidence of sacroiliitis and 38 of the 54 patients without MRI evidence of sacroiliitis. No features of inflammation were found on needle biopsy in 24 of the patients, including the remaining 16 patients who did not have sacroiliitis on MRI. The sensitivity and specificity of MRI for the early diagnosis of sacroiliitis in these patients were 37.7% and 100%, respectively. Thirty-four patients with pathologic evidence of sacroiliitis were followed up for 5-10 years. At the study end point, 16 of these 34 patients continued to show grade I or lower changes on CT, and 18 had changes of grade II or higher. These 18 patients included 7 of the 8 patients with evidence of sacroiliitis on MRI and 6 of the 20 patients confirmed not to have MRI evidence of sacroiliitis at baseline. CONCLUSION: MRI, though of low sensitivity, is specific for the diagnosis of early sacroiliitis. Sacroiliitis can be detected earlier by needle biopsy than by MRI.

Epidemiologic study of soft tissue rheumatism in Shantou and Taiyuan, China.

BACKGROUND: Soft tissue rheumatism is a group of common rheumatic disorders reported in many countries. For investigating the prevalence rate of soft tissue rheumatism in different population in China, we carried out a population study in Shantou rural and Taiyuan urban area. METHODS: Samples of 3915 adults in an urban area of Taiyuan, Shanxi Province, and 2350 in a rural area of Shantou, Guangdong Province were surveyed. Modified International League of Association for Rheumatology (ILAR)-Asia Pacific League of Association for Rheumatology (APLAR) Community Oriented Program for Control of Rheumatic Diseases (COPCORD) core questionnaire was implemented as screening tool. The positive responders were then all examined by rheumatologists. RESULTS: Prevalence rate of soft tissue rheumatism was 2.0% in Taiyuan, and 5.3% in Shantou. Rotator cuff (shoulder) tendinitis, adhesive capsulitis (frozen shoulder), lateral epicondylitis (tennis elbow), and digital flexor tenosynovitis (trigger finger) were the commonly seen soft tissue rheumatism in both areas. Tatarsalgia, plantar fasciitis, and De Quervain's tenosynovitis were more commonly seen in Shantou than that in Taiyuan. Only 1 case of fibromyalgia was found in Taiyuan and 2 cases in Shantou. The prevalence of soft tissue rheumatism varied with age, sex and occupation. CONCLUSIONS: Soft tissue rheumatism is common in Taiyuan and Shantou, China. The prevalence of soft tissue rheumatism was quite different with different geographic, environmental, and socioeconomic conditions; and varying with age, sex, and occupation. The prevalence of fibromyalgia is low in the present survey.

Rheumatic diseases in China.

INTRODUCTION: Epidemiological studies of rheumatic diseases have been conducted during the past 20 years in China. The aim of this study was to clarify prevalence rates of common rheumatic diseases in China. METHODS: Relevant reports of population-based surveys conducted from 1980 to 2006 were retrieved. Studies using the World Health Organization-International League of Associations for Rheumatology COPCORD (Community Oriented Program for Control of Rheumatic Diseases) protocol and those that did not employ this protocol but were published in recognized journals were identified and analyzed. RESULTS: Thirty-eight surveys including 241,169 adults from 25 provinces/cities were pooled for analysis. The prevalence of rheumatic complaints ranged from 11.6% to 46.4%, varying by locality, study protocol and age of the people surveyed. Prevalence of symptomatic osteoarthritis (OA) varied from 5.1% to 20.8%, with common sites of involvement being the lumbar spine, knee joint and cervical spine. Compared with rates of radiographic and symptomatic knee OA in the USA, elderly men in Beijing exhibited similar prevalence rates and elderly women exhibited a higher prevalence. The prevalence of hip OA and hand OA was much lower in Chinese than in Caucasian populations, but both kinds of OA were more common in coal miners. The prevalence of ankylosing spondylitis ranged from 0.2% to 0.54% among Han ethnic Chinese and were lower among mixed ethnic populations. The prevalence of psoriatic arthritis ranged from 0.01% to 0.1%, and that of reactive arthritis was 0.02%; undifferentiated spondyloarthropathy was identified in 0.64% to 1.2% of the individuals included in the surveys. The prevalence of rheumatoid arthritis (RA) ranged from 0.2% to 0.93%, with the highest rate being reported from a Taiwan urban area. In mainland China there were no significant differences in prevalence of RA between the northern and southern parts of China, or between different ethnic groups. The prevalence of hyperuricemia increased after the 1980s. The prevalence of gout was found to have increased in recent decades from 0.15% to 1.98%, apart from in the Taiwan aborigines, among whom the highest prevalence rate of 11.7% was recorded. The prevalence of primary Sjögren's syndrome in Beijing was 0.77% by the Copenhagen criteria and 0.33% by the San Diego criteria. The prevalence of soft tissue rheumatism was 2.5% to 5.7%. Fibromyalgia was seldom observed in China. CONCLUSION: Rheumatic diseases are common in China. The prevalence of rheumatic complaints varied with the locality surveyed. The prevalence of OA is comparable with that in Western countries but varies in terms of joint involvement. The prevalence of ankylosing spondylitis is similar to that in Caucasians. Except in Taiwan, the prevalence of RA in China is lower than that in developed countries. The prevalence of hyperuricemia and gout increased after the 1980s, but it remains lower than that in developed countries. More studies are required to evaluate prevalence rates among minority groups in the west and northwest parts of China, and further study is needed to address fibromyalgia in China.

Risk factors associated with rheumatic complaints: a WHO-ILAR COPCORD study in Shantou, Southeast China.

OBJECTIVE: To validate the differences of the prevalence of rheumatic symptoms between the north and south part of China and to investigate the associated risk factors for rheumatic complaints in Shantou, China. METHODS: Four samples together comprising 10,638 people > or = 16 years of age were surveyed in 1987, 1992, 1995, and 1999. The protocol of the ILAR-China Collaborative Study or the WHO-ILAR COPCORD Core Questionnaire was implemented. Data on rheumatic symptoms that were part of these surveys were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints was increasing in the Shantou area during the recent decade (in 1987 11.6%, 1992 12.5%, 1995 16.0%, and 1999 19.8%). However, it was still lower than the rate in Beijing, China, in 1987 (40.0%). Rheumatic symptoms were more prevalent in women than in men, and were more frequently seen in the elderly than in young people. The most frequently involved site was the low back followed by the knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in the urban school-age population group. The prevalence of knee pain was significantly higher in people living in multi-story buildings without elevators compared with those living in single-story houses. The peak value of bone mineral density (BMD) in the Shantou population was 0.839 +/- 0.085 g/cm2 in men, and 0.723 +/- 0.064 g/cm2 in women, significantly higher than that reported in 13 other provinces and cities of China including Beijing. The sense of seeking a physician's care was higher in the population with a higher prevalence of rheumatic symptoms than that in the group with a lower prevalence of complaints. However, no significant difference was found in the rate of disability among the different population samples. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than in Beijing. Socioeconomic status, environmental differences (e.g., Shantou in the southern and Beijing in the northern part of China), sex, age, occupation, ergonomics, BMD, and awareness of seeking medical care might all be risk factors associated with the prevalence of rheumatic complaints.

[Study on the associated risk factors of rheumatic pain: a ILAR-China, WHO COPCORD Shantou study].

OBJECTIVE: To validate the difference on the prevalence of rheumatic symptoms between north and south parts of the country and to study the associated risk factors of rheumatic complaints in Shantou city, China. METHODS: A total number of 10 638 people at above 16 years of age from four samples, were surveyed in 1987, 1992, 1995, and 1999. Protocol of International League Against Rheumatism (ILAR)-China collaborative study or WHO-ILAR community oriented program for control of rheumatic disease(COPCORD) core questionnaire was implemented. Data on related rheumatic symptoms were collected and analyzed. RESULTS: The prevalence rate of rheumatic complaints had been increasing in Shantou area during the last decade (in 1987 11.6%, 1992 12.5%, 1995 16.0% and 1999 19.8%) but still lower than that seen in Beijing, China in 1987(40.0%). Rheumatic symptoms were more prevalent in females than in males, in elderly than in young people with most frequently involved site happened in low back area, followed by knee and neck. Lumbar pain was more frequent among rural residents, while neck pain was more prevalent in urban school students. Prevalence of knee pain was significantly higher in people living in multi-storey buildings without elevator than those living in single-storey houses. The peak values of Bone Mineral Density in Shantou population were (0.839 +/- 0.085) g/cm2 in men, and (0.723 +/- 0.064) g/cm2 in women, significantly higher than that reported in 13 other provinces and cities including Beijing. The sense of seeking for medical help was higher in population with higher prevalence of rheumatic symptoms than that in lower complaints group. However, no significant difference was found in the rates of disability among the different populations. CONCLUSION: The prevalence rate of rheumatic complaints was lower in Shantou than that in Beijing. Socio-economic status, environment, sex, age, occupation, ergonomics, bone mineral density, and awareness of seeking medical care might have been the associated risk factors to the prevalence of rheumatic complaints.

Low prevalence of knee and back pain in southeast China; the Shantou COPCORD study.

OBJECTIVE: To determine whether the previously noted low prevalence of knee pain (KP) and lumbar pain (LP) in rural southern China compared with the high prevalence observed in North China was also true in a southern urban population. METHODS: A population based sample of 2040 adults > or = 16 years of age was studied in Chenghai City, close to the rural area previously studied on the southeast coast of China. Primary healthcare workers administered the COPCORD Phase I and II questionnaires. Those with rheumatic symptoms were recalled for medical examination, with a response rate at examination (phase III) of 98.4%. Those suspected of having arthritis had radiographs and laboratory tests. Prevalences were age and sex adjusted to the total of populations previously reported. RESULTS: (1) The prevalence for all rheumatic symptoms at phase III was 18.1%. Of the 7.5% with KP, 55% had osteoarthritic changes on radiograph (KOA) compared with 29% of a sample with no KP (p < 0.001). Of the 11.5% with LP, 69% had degenerative changes on lumbar spine radiograph (LOA). (2) Of residents in single-level houses the prevalence was 5.6% for KP and 7.9% for LP, whereas in 4 to 6-level apartment buildings these rates were significantly higher, 9.1% and 16.2%, respectively. All these pain rates were significantly lower than noted in rural North China. The prevalence of pain together with radiographic OA changes in the knee (KOA) was half the rate in single-floor residents (2.7%) compared to apartment residents (5.3%), as was lumbar spine degenerative disease (5.3% vs 11.5%). CONCLUSION: The prevalence of knee and lumbar spine pain in this southern urban sample was confirmed to be much lower than in the rural sample in the North, although higher than in the rural sample in the South. Comparing COPCORD studies of Han Chinese in Shanghai and Malaysia there was a decrease in prevalence of knee and back pain with latitude, suggesting an association with climate. Knee and back pain and radiological degenerative changes in the knee and lumbar spine were twice as prevalent in apartment residents than in those living in older single-level houses. Further study is needed to explain these observations.

[Needle biopsy of spondyloarthropathy: pathological features and clinical significance].

OBJECTIVE: To study the pathological features of sacroiliitis, aiming at improving the early diagnosis of ankylosing spondylitis (AS). METHODS: CT guided needle biopsy of sacroiliac joint (SIJ) was performed in 96 cases of spondyloarthropathy (SpA) patients with 3 autopsy materials of non-SpA sacroiliac joints serving as control. Pathological features were studied by two independent observers. Clinical data were collected and analyzed. RESULTS: No pathological change was noticed in the control group. Among the 96 cases of SpA, pathological changes were found in 76 cases, including bone marrow inflammation, pannus formation, subchondral bony plate destruction, cartilage degeneration/erosion, synovitis, and enthesitis. The aforementioned first 4 findings were present in 45 cases of grade 0/I CT sacroiliitis. In the synovial specimens obtained, synovitis was seen in some cases of grade I and all of >/= grade II CT sacroiliitis,while no inflammatory change was noticed in all cases of grade 0 CT sacroiliitis. Frequency rate of cartilage erosion and ossification in grade 0/I CT sacroiliitis was the lowest in comparison with the other groups. Moreover, in cases of grade 0/I CT sacroiliitis, cartilage erosion only present at the bony plate side, while the joint cavity side was not affected. The inflammatory index was significantly lower in cases of grade IV CT sacroiliitis than that in the other groups. Enthesitis only presented in some cases of >/= grade II CT sacroiliitis. Among the 65 undifferentiated spondyloarthropathy patients, 45 were diagnosed as AS after SIJ pathological examination. The mean disease duration of these 45 cases was significantly shorter than that in cases of >/= grade II CT sacroiliitis. CONCLUSIONS: Inflammatory changes of SIJ did exist in cases of the < grade II CT sacroiliitis. Sacroiliitis probably initiated with bone marrow inflammation, followed by pannus formation, subchondral bony plate destruction, and cartilage degeneration/erosion, eventually leading to fibrosis, ossification and joint fusion. Synovitis and enthesitis were not the very early changes of sacroiliitis. Pathological examination was beneficial to the early diagnosis and differential diagnosis of ankylosing spondylitis.