Rheumatic diseases in China

Reactive oxygen species: the 2-edged sword of osteoarthritis

The degenerative joint disease osteoarthritis (OA) is the most prevalent form of chronic musculoskeletal disease worldwide, and it commonly afflicts the elderly population. OA-induced impairment of joint function can debilitate normal physical activity, and in more severe cases, it can lead to complete joint destruction and loss of independence or even mobility. The pathophysiology of OA remains to be fully elucidated, despite the extensive research efforts into this complex disease. Studies have revealed that reactive oxygen species (ROS) can contribute to the onset and progression of OA by inducing indispensable chondrocyte death and matrix degradation. However, ROS are also key components of many normal physiological processes, and at moderate levels, they act as indispensable second messengers. This review focuses on the dual role of ROS in cartilage, with the aim of gaining insights into how ROS can be regulated such that its beneficial effects are maintained and its detrimental effects are eliminated.

Power Doppler ultrasonography in the evaluation of infliximab treatment for sacroiliitis in patients with ankylosing spondylitis

The aim of this study was to evaluate the feasibility of using power Doppler ultrasound (PDUS) to detect changes in the sacroiliac joint regions after infliximab (an anti-TNF-α blocker) treatment in active axial ankylosing spondylitis (AS) patients. A total of 110 sacroiliac joints in 55 patients with active AS were detected by PDUS before and after the infliximab treatment. The color flow signals inside the sacroiliac joints were observed, and the resistance index (RI) was measured. The clinical condition of the AS patients was improved compared with their condition before the infliximab treatment. Before the treatment, color flow signals were observed in 103 joints, and the mean RI value was 0.56 ± 0.06. Three months after the first infliximab treatment, color flow signals were observed in 50 joints, and the mean RI value was 0.87 ± 0.11. There were more blood flow signals in the sacroiliac joints before the infliximab treatment in patients with active AS (p < 0.01), and the mean RI value was higher after the infliximab treatment (p < 0.01). The blood flow signals in the sacroiliac joints became weaker or even disappeared and the RI values increased in patients with active sacroiliitis after infliximab treatment. This result shows that PDUS can be used in the follow-up of patients with axial AS.

The association between hepatitis B virus infection and disease activity, synovitis, or joint destruction in rheumatoid arthritis

The prevalence of chronic hepatitis B virus (HBV) infection in China is high. Four percent of patients with HBV infection can present with polyarthritis and positive rheumatic factor similar to rheumatoid arthritis (RA). Here, we investigated the association between HBV infection and serological, radiological, or histological disease status in RA. According to HBV infection status, 223 consecutive hospitalized Chinese patients with RA were divided into the groups of chronic HBV infection, past HBV infection, and no HBV infection. Clinical data and hand radiographs were collected. Synovium was obtained by closed-needle biopsy, and serial tissue sections were stained immunohistochemically for HBV surface antigen (HBsAg) and cluster of differentiation (CD) markers. (1) The prevalence of HBsAg positivity and chronic hepatitis B in RA was consistent with the age-matched general Chinese population (11.2 vs. 8.7 %, 1.7 vs. 1.0 %, respectively, P > 0.05). (2) Clinical parameters, disease activity score in 28 joints, or Sharp scores showed no significant difference among the three groups in 206 RA or 140 treatment-naïve patients, both with active disease (all P > 0.05). (3) Synovial immunohistochemical staining showed negative HBsAg in ten RA patients with HBV carrier status and ten RA patients with past HBV infection. Except for higher subintimal CD3+ cell density in the past HBV infection group, Krenn's synovitis score, mean densities of subintima positive-staining cells (CD20, CD38, CD79a, and CD68), and CD34+ microvessel counts showed no significant difference among RA patients with HBV carrier status, past HBV infection, or no HBV infection (all P > 0.05). Chronic HBV infection may have no significant effect on disease activity, synovitis, or joint destruction in RA.

Immunogenetic study in Chinese population with ankylosing spondylitis: are there specific genes recently disclosed?

Purpose. Ankylosing spondylitis (AS) is a systemic, autoimmune disease resulting in the destruction of the affected joints. Over the past 5 years, several new genes or genetic regions associated with AS have been identified in the Chinese population. This paper aims to discuss the major findings and related potential mechanisms of these studies in our population. Recent Findings. In recent years, due to the rapid advances in computational genetics and technology, there has been an increasing list of well-validated genes or genetic regions associated with AS susceptibility. So far, several genes or genetic regions have now been reported in the Han ethnic Chinese population, containing the major histocompatibility complex (MHC), ERAP1, IL-23R, 12q12, 2p15, 5q14.3, and so on. Different hypotheses for disease mechanisms have been investigated on the basis of the functional studies of these genes or genetic regions. Summary. This paper tries to summarize the association of several candidate genes with risk for AS in the Han ethnic Chinese population and aims to identify the novel inflammatory pathways and provide potential strategies for better therapies.

Epidemiology and burden of osteoarthritis

BACKGROUND

Osteoarthritis (OA) is a degenerative joint disease involving the cartilage and many of its surrounding tissues. Disease progression is usually slow but can ultimately lead to joint failure with pain and disability. OA of the hips and knees tends to cause the greatest burden to the population as pain and stiffness in these large weight-bearing joints often leads to significant disability requiring surgical intervention.

SOURCES OF DATA

The article reviews the existing data on epidemiology of osteoarthritis and the burden of the disease.

AREAS OF AGREEMENT

Symptoms and radiographic changes are poorly correlated in OA. Established risk factors include obesity, local trauma and occupation. The burden of OA is physical, psychological and socioeconomic.

AREAS OF CONTROVERSY

Available data does not allow definite conclusion regarding the roles of nutrition, smoking and sarcopenia as risk factors for developing OA.

GROWING POINTS

Variable methods of diagnosing osteoarthritis have significantly influenced the comparability of the available literature.

AREAS TIMELY FOR DEVELOPING RESEARCH

Further research is required to fully understand how OA affects an individual physically and psychologically, and to determine their healthcare need.

Major trends in the manifestations and treatment of rheumatoid arthritis in a multiethnic cohort in Singapore

We analyzed the epidemiological changes of rheumatoid arthritis (RA) over three decades using patients from a single center in Singapore. All patients who fulfill the 1987 American College of Rheumatology criteria for RA were invited to enroll in a prospective disease registry. We analyzed the patient demographics, disease manifestation, management and patient-reported outcomes, including quality of life (QoL), in the three categories according to the year of disease onset: before 1989 (group I), 1990-1999 (group II) and after 2000 (group III). There were 1,153 patients with 231, 532 and 390 in groups I, II and III, respectively. The mean disease durations were 25, 12 and 4.8 years, respectively. The majority was female (84.1 %) and Chinese (76.6 %) with no socio-demographic differences across the three periods. The age of onset rises and the prevalence of rheumatoid factor falls with the proximity of disease onset. Patients with most recent disease onset had the earliest access to the rheumatologist. They also had the highest tender and swollen joint counts, lowest deformed joint count and highest remission rate. Patients in group I report better mental and emotional QoL though many developed marked disability. We have documented changes of the manifestations of RA that are dependent and independent of improved treatment. Significant differences in accessibility to the rheumatologist, RA activity, functional capacity, quality of life and comorbidities were seen in subsequent cohorts due to treatment evolution and more efficient healthcare delivery.

Safety of tumor necrosis factor inhibitors use for rheumatoid arthritis and ankylosing spondylitis in Africa, the Middle East, and Asia: focus on severe infections and tuberculosis

Multiple studies of patients in Western countries with rheumatoid arthritis (RA) and ankylosing spondylitis (AS) have indicated increased risk for active tuberculosis (TB) and other infections among these individuals. It has also been consistently reported that patients receiving tumor necrosis factor (TNF) inhibitors for these conditions have higher rates of active TB and other infections than RA or AS patients not receiving these medications. These issues have been studied less extensively in the Asia and Africa-Middle East regions, and information from these regions is important because of higher rates of TB in the general population. This paper reviews studies of RA and AS patients from Asia, Africa, and the Middle East who received TNF inhibitors. A literature search was conducted using http://www.ncbi.nlm.nih.gov/pubmed to collect and report these data. The years included in the PubMed literature search ranged from January 2000 to October 2011. Additionally, information from the China Hospital Knowledge Database was used to report data from Chinese patients with RA and AS treated with TNF inhibitors. Results from these studies indicate that the risk for active TB and other infections in AS and RA patients from Asia, Africa, and the Middle East are increased in patients receiving TNF inhibitors and that the risk is higher among those treated with monoclonal antibodies versus soluble TNF receptor.

Androgen receptor genetic variants in male patients with ankylosing spondylitis in Taiwan

AIM

Ankylosing spondylitis (AS) is a chronic rheumatic disorder with gender differences. The aim of study was to investigate the association between polymorphisms of the androgen receptor (AR) gene and the susceptibility to AS in Taiwanese men of Han Chinese descent.

METHODS

We conducted a case-control study with 92 male AS patients and 108 healthy controls. Trinucleotide (CAG and GGC) repeats and seven single nucleotide polymorphisms (SNPs) rs962458, rs6152, rs1204038, rs5918757, rs2361634, rs6624304 and rs1337080 in the AR gene were genotyped.

RESULTS

We found that only one patient had polymorphic SNPs of the AR gene. None of the genotyped SNPs in the AR gene, originally found in Caucasians, was polymorphic in the Taiwanese men. Neither CAG nor GGC repeat lengths in the AR gene had a significant relationship with human leukocyte antigen (HLA)-B27 positivity or disease severity in AS.

CONCLUSION

There were no differences in CAG and GGC lengths in the AR gene between AS and the controls. None of the genotyped SNPs in AR gene are detected to be polymorphic in male Taiwanese, which indicates that the effect of AR gene on AS may be ethnic-specific and may be conserved in East Asians compared to Caucasian populations. Still, additional studies using large sets of subjects deserve further attention, since our sample size was small with limited statistical power and supporting evidence for association between the AR gene and AS risk in the Japanese population exists.

Cost effectiveness of different treatment strategies in the treatment of patients with moderate to severe rheumatoid arthritis in china

Background

To analyse the cost-effectiveness of traditional disease-modifying anti-rheumatic drugs (tDMARDs) compared to biological therapies from the perspective of Chinese society.

Methodology/Principal Findings

A mathematical model was developed by incorporating the clinical trial data and Chinese unit costs and treatment sequences from a lifetime perspective. Hypothetical cohorts with moderate to severe RA were simulated. The primary outcome measure–quality-adjusted life years (QALYs)–was derived from disease severity (HAQ scores). Primary analysis included drug costs, monitoring costs, and other costs. Probabilistic and one-way sensitivity analyses were performed. Treatment sequences that included TNF antagonists and rituximab produced a greater number of QALYs than tDMARDs alone or TNF antagonists plus DMARDs. In comparison with tDMARDs, the incremental cost-effectiveness ratios (ICERs) for etanercept, infliximab, and adalimumab without rituximab were $77,357.7, $26,562.4 and $57,838.4 per QALY and $66,422.9, $28,780.6 and $50,937.6 per QALY, for etanercept, infliximab, and adalimumab with rituximab. No biotherapy was cost-effective under the willingness to pay threshold when the threshold was 3 times the per capita GDP of China. When 3 times the per capita GDP of Shanghai used as the threshold, infliximab and rituximab could yield nearly 90% cost-effective simulations in probabilistic sensitivity analysis.

Conclusions/Significance

tDMARD was the most cost-effective option in the Chinese healthcare setting. In some relatively developed regions in China, infliximab and rituximab may be a favorable cost-effective alternative for moderate to severe RA.

Association of FCRL4 polymorphisms on disease susceptibility and severity of ankylosing spondylitis in Chinese Han population

Previous studies have found that the Fc receptor-like (FCRL) molecule, involved in controlling B cell signaling, may contribute to the autoimmune disease process. Many studies have reported the relation of FCRL gene family with SLE and RA. We hypothesized that FCRL4 may be a key gene for ankylosing spondylitis (AS) development. To test this hypothesis, we screened FCRL4 polymorphisms in the Chinese Han population. Five tag single nucleotide polymorphisms (SNPs), including rs14335, rs849826, rs10489674, rs2778003, and rs2777963, were selected. Using a case-control study, five tag SNPs, which captured the majority of known common variation within FCRL4 gene, were selected and genotyped by Multiplex Snapshot technique. We analyzed 299 patients and 300 controls from China. The genotype analysis demonstrated that one of the FCRL4 tag SNPs rs2777963 TT genotype may be a risk factor of AS (χ(2) = 7.374, p = 0.024). The haplotype analysis indicated that there were no significant differences between AS cases and controls. Patients with AS who had rs14335 AA genotype had a significantly declined visual analogue scale patient's global assessment scores compared to those with the GG genotype (31.21 ± 26.25 vs 40.54 ± 25.40, p = 0.035) and GA genotype (38.29 ± 24.94 vs 40.54 ± 25.40, p = 0.044), and in locus rs10489674, TT genotype had significantly increased Bath Ankylosing Spondylitis Disease Activity Index scores compared to those with the CC genotype (4.73 ± 2.43 vs 3.15 ± 1.61, p = 0.003) and CT genotype (4.73 ± 2.43 vs 2.97 ± 1.71, p = 0.001). The FCRL4 polymorphisms may play an important role in the susceptibility and severity of AS in the Chinese Han population.

Early psoriatic arthritis

Psoriatic arthritis is an inflammatory musculoskeletal disease associated with psoriasis that is usually seronegative for rheumatoid factor. Psoriatic arthritis affects men and women equally, usually during the fourth decade, although it may affect children and octogenarians. Psoriatic arthritis may lead to deformities, joint damage, reduced quality of life and function. Early detection and treatment may prevent untoward outcomes.

Changes in daily physical activity before and after total hip arthroplasty. A pilot study using accelerometry

The present single-centre prospective follow-up study assessed the objective changes in physical activity undertaken before and after total hip arthroplasty (THA) using accelerometry. We enrolled 12 female patients who underwent home-based accelerometry assessment one month before and six months after the THA procedure. We assessed the daily amount of physical activity and energy expenditure related to physical activities. We also recorded the intensity of the physical activity, and pre- and post-operative clinical evaluation with the Harris Hip Score (HHS). At 6 months after surgery, we found a statistically significant increase of the total energy cost of physical activity (DA) (P=0.02), without significant increase of activity time (P>0.05). The energy cost of moderate/vigorous activity was statistically significant increased after surgery (P=0.008). Finally, HHS improved form 53.9±15.3 pre-operatively to 78.1±12.2 post-operatively (P=0.03). In our patients, the improvement was significant only for the total energy cost of daily activity. Thus, although patients did not exhibit a more active lifestyle, as shown by the slight increase of the activity time, they significantly increased the amount of moderate or vigorous activities performed after surgery.

Mortality due to coronary heart disease and kidney disease among middle-aged and elderly men and women with gout in the Singapore Chinese Health Study

OBJECTIVES

Whether the link between gout and mortality is causal or confounded by lifestyle factors or comorbidities remains unclear. Studies in Asia are warranted due to the rapid modernisation of the locale and ageing of the population.

METHODS

The association between gout and mortality was examined in a prospective cohort, the Singapore Chinese Health Study, comprising 63 257 Singapore Chinese individuals, aged 45-74 years during the enrolment period of 1993-8. All enrollees were interviewed in person on lifestyle factors, current diet and medical histories. All surviving cohort members were contacted by telephone during 1999-2004 to update selected exposure and medical histories (follow-up I interview), including the history of physician-diagnosed gout. Cause-specific mortality in the cohort was identified via record linkage with the nationwide death registry, up to 31 December 2009.

RESULTS

Out of 52 322 participants in the follow-up I interview, 2117 (4.1%) self-reported a history of physician-diagnosed gout, with a mean age at diagnosis of 54.7 years. After a mean follow-up period of 8.1 years, there were 6660 deaths. Relative to non-gout subjects, subjects with gout had a higher risk of death (HR 1.18; 95% CI 1.06 to 1.32), and specifically from death due to coronary heart disease (CHD) (HR 1.38, 95% CI 1.10 to 1.73) and kidney disease (HR 5.81, 95% CI 3.61 to 9.37). All gout-mortality risk associations were present in both genders but the risk estimates appeared higher for women.

CONCLUSION

Gout is an independent risk factor for mortality, and specifically for death due to CHD and kidney disease.

Prevalence of autoimmune diseases in in-patients with schizophrenia: nationwide population-based study

BACKGROUND

The association between autoimmune diseases and schizophrenia has rarely been systematically investigated.

AIMS

To investigate the association between schizophrenia and a variety of autoimmune diseases and to explore possible gender variation in any such association.

METHOD

Taiwan's National Health Insurance Research Database was used to identify 10 811 hospital in-patients with schizophrenia and 108 110 age-matched controls. Univariate and multiple logistic regression analyses were performed, separately, to evaluate the association between autoimmune diseases and schizophrenia. We applied the false discovery rate to correct for multiple testing.

RESULTS

When compared with the control group, the in-patients with schizophrenia had an increased risk of Graves' disease (odds ratio (OR) = 1.32, 95% CI 1.04-1.67), psoriasis (OR = 1.48, 95% CI 1.07-2.04), pernicious anaemia (OR = 1.71, 95% CI 1.04-2.80), celiac disease (OR = 2.43, 95% CI 1.12-5.27) and hypersensitivity vasculitis (OR = 5.00, 95% CI 1.64-15.26), whereas a reverse association with rheumatoid arthritis (OR = 0.52, 95% CI 0.35-0.76) was also observed. Gender-specific variation was found for Sjögren syndrome, hereditary haemolytic anaemia, myasthenia gravis, polymyalgia rheumatica and dermatomyositis.

CONCLUSIONS

Schizophrenia was associated with a greater variety of autoimmune diseases than was anticipated. Further investigation is needed to gain a better understanding of the aetiology of schizophrenia and autoimmune diseases.

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.

Genome-wide association study of skin complex diseases

Complex diseases are caused by both genetic and environmental factors. Over decades, scientists endeavored to uncover the genetic myth of complex diseases by linkage and association studies. Since 2005, the genome-wide association study (GWAS) has been proved to be the most powerful and efficient study design thus far in identifying genetic variants that are associated with complex diseases. More than 230 complex diseases and traits have been investigated by this approach. In dermatology, 10 skin complex diseases have been investigated, a wealth of common susceptibility variants conferring risk for skin complex diseases have been discovered. These findings point to genes and/or loci involved in biological systems worth further investigating by using other methodologies. Certainly, as our understanding of the genetic etiology of skin complex diseases continues to mature, important opportunities will emerge for developing more effective diagnostic and clinical management tools for these diseases.

Association among serum uric acid, cardiovascular risk, and arterial stiffness: a cross-sectional study in She ethnic minority group of Fujian Province in China

OBJECTIVES

To investigate the association between serum uric acid levels, cardiovascular risk, and arterial stiffness in She ethnic minority in South China's Fujian Province.

METHODS

5109 participants aged 20-79 yr were enrolled in analysis. Tpeak-Tend interval (Tp-e), QT interval, and height of the R wave in lead aVL (aVLR) were measured on 12-lead electrocardiogram (ECG), and Minnesota code-indicated major abnormal ECG MA-ECG was used as a risk indicator of cardiovascular disease. Arterial stiffness was assessed by brachial-ankle pulse wave velocity (baPWV).

RESULTS

Longer Tp-e interval, greater Tp-e/QT ratio, and higher aVLR were observed in the highest quartile of uric acid level. The incidence of MA-ECG was gradually increased from lowest to highest quartile of serum uric acid in males (p for trend <0.01). After adjusting traditional cardiovascular risk factors, multivariate analysis revealed that the fourth quartile of serum uric acid level was independently associated with MA-ECG in males [odds ratios (OR) (95% confidence interval): 2.129 (1.376-3.295)] but not in females. Serum uric acid was also associated with abnormal baPWV, when adjusted for atherogenic confounders. Compared with the lowest serum uric acid quartile, the OR (95% confidence interval) of the second, third, and fourth quartile were 1.920 (1.246-2.957), 1.650 (1.064-2.558), and 2.501 (1.600-3.908) in males.

CONCLUSION

Among China's She ethnic minority, uric acid level was independently related to arterial stiffness assessed by baPWV in both genders. The evaluation of uric acid level was related to higher cardiovascular risk in males but not in females.

Epidemiology of eight common rheumatic diseases in China: a large-scale cross-sectional survey in Beijing

OBJECTIVE

To investigate the prevalence of eight common rheumatic diseases in a large Chinese population.

METHODS

A population-based epidemiological investigation of the prevalence of eight common rheumatic diseases in a suburb of Beijing was conducted in 14 642 individuals. A community-based survey was carried out using a screening questionnaire. Positive responders were included in a clinical and laboratory examination. Diagnosis was based on the criteria of ACR or those used widely in literature.

RESULTS

A total of 10 556 inhabitants were interviewed. Forty-three cases of RA were identified with an age-adjusted prevalence of 0.28% (95% CI 0.19%, 0.41%). Gout was diagnosed with a crude prevalence of 0.09% (95% CI 0.05%, 0.17%). Psoriasis was reported in 28 individuals with a prevalence of 0.27% (95% CI 0.18%, 0.38%). This included two cases diagnosed with PsA, resulting in a prevalence of 7.14% (95% CI 0.88%, 23.5%) in psoriasis patients and 0.02% (95% CI 0%, 0.07%) in the general population. Three individuals were identified with SLE, with a prevalence of 0.03% (95% CI 0%, 0.06%). One individual was identified with SSc and the calculated prevalence was 0.01% (95% CI 0%, 0.05%). One case of Behçet's disease was identified, giving a prevalence of 0.01% (95% CI 0%, 0.05%).

CONCLUSION

This large-scale epidemiological survey provides an estimate of the burden of rheumatic diseases in China.

Primary biliary cirrhosis and Sjögren's syndrome: autoimmune epithelitis

Primary biliary cirrhosis (PBC) has been often coined a model autoimmune disease based on the homogeneity amongst patients, the frequency and similarity of antimitochondrial antibodies, including the highly directed immune response to pyruvate dehydrogenase (PDC-E2). A significant number of patients with PBC suffer from sicca and amongst these, there are patients who also have classic Sjögren's syndrome. Indeed, both PBC and Sjögren's syndrome are characterized by inflammation of target epithelial elements. Both diseases can be considered on the basis of a number of other related clinical aspects, including proposed unique apoptotic features of the target tissue, the role of secretory IgA, and the frequency with which both diseases overlap with each other. Indeed, PBC may be considered a Sjögren's syndrome of the liver, whereas Sjögren's syndrome can be equally discussed as PBC of the salivary glands. Dissection of the genetic predispositions for both diseases and especially the molecular basis of effector mechanisms, will become critical elements in developing new therapies.

Epidemiology of gout: an update

Gout is the most common inflammatory joint disease in men, characterised by formation of monosodium urate (MSU) crystals in the synovial fluid of joints and in other tissues. The epidemiology of gout provides us with the understanding of the disease distribution and its determinants. In an attempt to update the knowledge on the topic, more recent research reports on the descriptive epidemiology of gout are reviewed in this article. The review describes clinical characteristics and case definitions of gout, including the Rome and New York diagnosis criteria of gout, '1977 American Rheumatism Association (ARA) criteria' and the 10 key propositions of the European League Against Rheumatism (EULAR) recommendations. Gout incidence, prevalence, morbidity and mortality, geographical variation of the disease, relevant risk factors for both the occurrence and outcome of gout and trends of the disease over time are then described. Difficulties in obtaining the information and data reported are also discussed.

Seronegative spondyloarthritis

Seronegative spondyloarthritis (SpA) is a group of inflammatory rheumatic diseases with common clinical and aetiological features, including axial and peripheral inflammatory arthritis, enthesitis, extra-articular manifestations and a close link to the presence of the human leucocyte antigen (HLA)-B27 epitope. Ankylosing spondylitis is the most common of the SpA diseases, with prevalence in the Caucasian population ranging between 0.15% and 1.8%, generally higher in populations with a higher background prevalence of HLA-B27 positivity. Incidence has been estimated between 0.49 (Japan) and 10 (Norway) per 100,000. The prevalence of psoriatic arthritis ranges from 0.02% to 0.2%, and the incidence in the normal population is 7.2 per 100,000 per year. In patients with existing psoriasis, the prevalence of psoriatic arthritis rises to 6-42%. The prevalence of reactive arthritis is dependent on the background incidence of gastrointestinal or genitourinary infections; incidence has been described as up to 30-40 per 100,000. SpA symptoms are present in up to 50% of patients with inflammatory bowel disease.

Confirmation of C4 gene copy number variation and the association with systemic lupus erythematosus in Chinese Han population

The distribution of complement component 4 (C4) gene copy number (GCN) has been validated in European populations. Meanwhile, C4 gene has been identified as a susceptibility gene for systemic lupus erythematosus (SLE). However, the association and the possible phenotype significance remain to be determined intensely in the Chinese population. This study was designed to validate the distribution of C4 GCNs in Chinese Han and the correlation between C4 GCNs and SLE using quantitative real-time polymerase chain reaction in 924 SLE patients and 1,007 controls. The results presented distribution of C4 GCNs in healthy populations and also showed that lower C4 GCN was a risk factor for SLE and higher C4 GCN was a protective factor against the disease susceptibility, which was similar to the report in the Caucasian population. Furthermore, we found the association between C4A GCN and disease subphenotypes of arthritis with SLE. We conclude that the association of C4 GCN with SLE was replicated in Chinese Han population, which highlighted the importance of C4 in SLE pathogenesis of diverse populations.

The epidemiology of uric acid and fructose

During the past few decades, the mean serum uric acid levels and the prevalence of hyperuricemia in the general population appear to have increased. Correspondingly, the prevalence and incidence of gout have doubled. Potential reasons behind these trends include the increasing prevalence of obesity and metabolic syndrome, Western lifestyle factors, increased prevalence of medical conditions (eg, renal conditions, hypertension, and cardiovascular disorders), and use of medications that increase uric acid levels (eg, diuretics and low-dose aspirin). The substantial increase in sugar-sweetened soft drinks and associated fructose consumption also has coincided with the secular trend of hyperuricemia and gout. Recently, several large-scale epidemiologic studies have clarified a number of these long-suspected risk factors in relation with hyperuricemia and gout. Furthermore, recent studies have illuminated the substantial comorbidities of hyperuricemia and gout, particularly metabolic-cardiovascular-renal conditions. Although many prospective studies have suggested an independent association between serum uric acid levels and the future risk of cardiovascular-metabolic morbidities and mortality, only a limited number of randomized clinical trials and observational studies recently have shown that the use of allopurinol can be beneficial against these outcomes. Because these data are scarce and the effects of allopurinol might not be limited to decreasing serum uric acid levels, the potential causal role of uric acid on these outcomes remains to be clarified with further studies.

The microbiome and rheumatoid arthritis

Humans are not (and have never been) alone. From the moment we are born, millions of micro-organisms populate our bodies and coexist with us rather peacefully for the rest of our lives. This microbiome represents the totality of micro-organisms (and their genomes) that we necessarily acquire from the environment. Micro-organisms living in or on us have evolved to extract the energy they require to survive, and in exchange they support the physiological, metabolic and immune capacities that have contributed to our evolutionary success. Although currently categorized as an autoimmune disorder and regarded as a complex genetic disease, the ultimate cause of rheumatoid arthritis (RA) remains elusive. It seems that interplay between predisposing genetic factors and environmental triggers is required for disease manifestation. New insights from DNA sequence-based analyses of gut microbial communities and a renewed interest in mucosal immunology suggest that the microbiome represents an important environmental factor that can influence autoimmune disease manifestation. This Review summarizes the historical clues that suggest a possible role for the microbiota in the pathogenesis of RA, and will focus on new technologies that might provide scientific evidence to support this hypothesis.

Susceptibility to ankylosing spondylitis: evidence for the role of ERAP1, TGFb1 and TLR9 gene polymorphisms

Genetic factors are thought to be crucial in the pathogenesis of ankylosing spondylitis (AS). Recent studies have reported that ERAP1, TGBβ1 and TLRs genes are likely to have association with AS in different populations. We carried out this study to determine whether single-nucleotide polymorphisms covering the three genes are associated with AS in a Chinese Han population. Genomic DNA was isolated from the peripheral blood of 328 patients with AS and 627 healthy blood donors from Jinan region as a case-control study. The diagnosis of AS was made according to the modified New York criteria. The ERAP1 rs27044, TGBβ1 rs1800470 and TLR9 rs55704465 were genotyped by a polymerase chain reaction--restriction fragment length polymorphism method. Strong association with AS was observed for marker rs27044, but no significant differences were observed between AS patients and controls in the frequencies of the carriership of the alleles rs55704465 and rs1800470. Our data thus indicate that ERAP1 likely constitutes one of AS-associated loci of susceptibility after HLA in Chinese Han population. On the contrary, TGFB1 and TLR9 variations show no association with the susceptibility of AS.

Current controversies in spondyloarthritis: SPARTAN

The Spondyloarthritis Research and Therapy Network (SPARTAN), founded in 2003 to promote research, education, and treatment of ankylosing spondylitis (AS) and related forms of spondyloarthritis (SpA), held its 7th Annual Research and Education Meeting in July 2009 in Houston, Texas. Current controversies in SpA discussed during the meeting included an update on the epidemiology of AS, axial SpA, and inflammatory back pain; the adequacy of the mSASS to assess radiographic involvement; the helpfulness of magnetic resonance imaging in assessing disease progression; the reliability of metrology in assessing damage; and whether biologic agents alter the course of AS. Presentations also were made on psoriasis in the SCID mouse model; the challenges and opportunities of SpA in China; a discussion of the special needs in managing SpA in Ibero-America, and the SPARK Survey in Europe and North America.

Psoriatic arthritis: a systematic review

Psoriatic arthritis is an inflammatory rheumatic disorder of unknown etiology occurring in patients with psoriasis. The Classification Criteria for Psoriatic Arthritis study group has recently developed a validated set of classification criteria for psoriatic arthritis with a sensitivity of 91.4% and a specificity of 98.7%. Three main clinical patterns have been identified: oligoarticular (≤ 4 involved joints) or polyarticular (≥ 5 involved joints) peripheral disease and axial disease with or without associated peripheral arthritis. In this context distal interphalangeal arthritis and arthritis mutilans may occur. According to other reports, also in our centre, asymmetric oligoarthritis is the most frequent pattern at onset. Axial disease has been estimated between 5% and 36% of patients. It is characterized by an irregular involvement of the axial skeleton with a predilection for the cervical spine. Recurrent episodes of enthesitis and dactylitis represent a hallmark of psoriatic arthritis. In around 20% of cases distal extremity swelling with pitting edema of the hands or feet is observed. Unilateral acute iridocyclitis, usually recurrent in alternate fashion, is the most frequent extra-articular manifestation, and accelerated atherosclerosis is the prominent comorbidity. The clinical course of peripheral and axial psoriatic arthritis is usually less severe than rheumatoid arthritis and ankylosing spondylitis, respectively. Local corticosteroid injections and non-steroidal anti-inflammatory drugs are recommended in milder forms. Sulphasalazine and methotrexate are effective in peripheral psoriatic arthritis. Recent studies have provided evidence on the efficacy of anti-tumor necrosis factor-α drugs to control symptoms and to slow or arrest radiological disease progression.

Epidemiology of systemic lupus erythematosus in Asia

In this paper we aim to review the prevalence, incidence and disease presentation of lupus patients in Asian populations. The database of the National Library of Medicine (MEDLINE) through PUBMED up to September 2009 was searched for relevant articles using the search terms 'systemic lupus erythematosus', 'epidemiology', and 'Asia'. Articles on lupus prevalence, incidence, and clinical manifestations were retrieved and their bibliographies further screened for relevant articles. Proceedings of national, regional, and international rheumatology and SLE conferences were likewise searched for relevant abstracts. Retrieval rate of relevant articles was approximately 80%. Prevalence and incidence figures are expressed per 100,000 populations. Among the articles reviewed, epidemiologic information was usually obtained through population surveys or hospital cohorts. Prevalence data are available from 24 countries, and generally fall within 30-50/100,000 population. However, one survey showed a higher prevalence of 70 (Shanghai), while three others showed a lower prevalence of 3.2-19.3 (India, Japan, Saudi Arabia). Only three countries have recorded incidence rates and these varied from 0.9 to 3.1 per annum. Thirty articles from 21 countries describe lupus disease presentation. Common manifestations include mucocutaneous lesions (seen in 52-98% of patients) and arthritis/musculoskeletal complaints (36-95%). Antinuclear antibodies were generally positive in 89-100% of patients, except for two studies. Renal involvement ranged from 18% to 100% with most articles reporting this in >50% of their patients. Discoid lesions, serositis, and neurologic involvement were the least frequently seen symptoms. There is varying epidemiologic information regarding systemic lupus erythematosus among countries in Asia. Prevalence rates usually fall within 30-50/100,000 population. Incidence rates, as reported from three countries, varied from 0.9/100,000 to 3.1% per annum. It is difficult to make generalizations about how the epidemiologic character of the disease varies from country to country. However, similarities in disease manifestations can be observed. .

Association of STAT3 and TNFRSF1A with ankylosing spondylitis in Han Chinese

OBJECTIVES

Recent association studies by the Australo-Anglo-American Spondyloarthritis Consortium (TASC) in Caucasian European populations from Australia, North America and the UK have identified a number of genes as being associated with ankylosing spondylitis (AS). A candidate gene study in a Han Chinese population was performed based on these findings to identify associated genes in this population.

METHODS

A case-control study was performed in a Han Chinese population of patients with AS (n = 775) and controls (n = 1587) from Shanghai and Nanjing. All patients met the modified New York criteria for AS. The cases and controls were genotyped for 115 single nucleotide polymorphisms (SNPs) tagging IL23R, ERAP1, STAT3, JAK2, TNFRSF1A and TRADD, as well as other confirmation SNPs from the TASC study, using the Sequenom iPlex and the ABI OpenArray platforms. Statistical analysis of genotyped SNPs was performed using the Cochran-Armitage test for trend and meta-analysis was performed using METAL. SNPs in AS-associated genes in this study were then imputed using MaCH, and association with AS tested by logistic regression.

RESULTS

SNPs in TNFRSF1A (rs4149577, p = 8.2 × 10⁻⁴), STAT3 (rs2293152, p = 0.0015; rs1053005, p = 0.017) and ERAP1 (rs27038, p = 0.0091; rs27037, p = 0.0092) were significantly associated with AS in Han Chinese. Association was also observed between AS and the intergenic region 2p15 (rs10865331, p = 0.023). The lack of association between AS and IL23R in Han Chinese was confirmed (all SNPs p > 0.1).

CONCLUSIONS

The study results demonstrate for the first time that genetic polymorphisms in STAT3, TNFRSF1A and 2p15 are associated with AS in Han Chinese, suggesting common pathogenic mechanisms for the disease in Chinese and Caucasian European populations. Furthermore, previous findings demonstrating that ERAP1, but not IL23R, is associated with AS in Chinese patients were confirmed.

Diagnostic utility of an anti-CCP point-of-care immunotest in Chinese patients with rheumatoid arthritis

BACKGROUND

Early and accurate diagnosis of rheumatoid arthritis (RA) has become increasingly important. The clinical significance of anti-cyclic citrullinated peptide (CCP) antibody in Chinese RA adults was studied using an anti-CCP2 rapid test.

METHODS

Anti-CCP antibody and rheumatoid factor (RF) were determined in 95 RA patients and 140 patients with rheumatic diseases other than RA.

RESULTS

Two hundred and thirty five subjects were enrolled in this study. Both sensitivity and specificity of anti-CCP2 ELISA (78.9% & 95.7%) were higher than those of RF (67.4% & 84.3%). The area under the receiver operating characteristic curve for anti-CCP2 ELISA was 0.852 (95% CI: 0.792-0.913) which was larger than that for RF 0.775 (95% CI: 0.710-0.840). Both sensitivity and specificity (75.8% and 92.9%) of the anti-CCP2 rapid test were comparable to the ELISA. However, the sensitivity (62.1%) of a combined strategy by measuring anti-CCP antibody and RF was even lower than either marker alone although the specificity (98.6%) was slightly improved.

CONCLUSIONS

Anti-CCP antibody is a valuable tool for diagnosis of RA in Chinese patients. With the use of the reliable and user-friendly anti-CCP rapid test, it may have an important role in the design of therapeutic strategies in RA patients.

The association between seven ERAP1 polymorphisms and ankylosing spondylitis susceptibility: a meta-analysis involving 8,530 cases and 12,449 controls

Besides the MHC gene, HLA-B27, ERAP1 is one of the non-MHC genes which also play key roles in the pathogenesis of AS. It has been reported that there is an association between ERAP1 polymorphisms and AS Risk. However, the results were inconclusive. The aim of the current study was to determine the contribution of ERAP1 polymorphisms to ankylosing spondylitis (AS) susceptibility. To derive a more precise estimation of the association, a meta-analysis was performed by searching the MEDLINE and EMBASE data base. The crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to access the strength of association between ERAP1 polymorphisms and AS risk. The pooled ORs were performed for minor allele versus major allele in all polymorphisms. Nine case-control studies consisting of 8,530 AS patients and 12,449 controls were identified in this meta-analysis. Except in rs27434 (P = 0.23), the significant correlation between ERAP1 polymorphisms and AS susceptibility has been detected in rs27044 (OR 1.57, P < 0.001), rs17482078 (OR 1.271, P < 0.001), rs10050860 (OR 0.772, P = 0.006), rs30187 (OR 1.348, P < 0.001), rs2287987 (OR 0.746, P < 0.001) and rs27037 (OR 1.257, P = 0.001). This meta-analysis demonstrates that the ERAP1 polymorphisms may play a significant role in susceptibility to AS. However, this result should be identified by more convincing experimental evidences in molecular level and population level.

The impact of rheumatoid arthritis on the burden of disease in urban China

OBJECTIVES

The aim of this study is to assess the burden of disease associated with the impact of rheumatoid arthritis in urban China. Burden of disease is considered from four perspectives: (i) health-related quality-of-life (HRQoL); (ii) health status; (iii) employment status; and (iv) absenteeism and presenteeism.

METHODS

Data are from the 2009 National Health and Wellness Survey (NHWS) of urban China. This is an internet-based survey and details the health experience of 13,007 respondents. The survey is representative of the urban China population at 18 years of age and over (18.1% of the total population). Of those responding to the survey, a total of 353 reported that they had been diagnosed with rheumatoid arthritis--an unweighted estimate of 2.65%. The sample design allows a comparison of those reporting rheumatoid arthritis with those not reporting this disease and, hence, a quantitative assessment of the burden of disease. Estimates of the quantitative impact of the presence of rheumatoid arthritis are through a series of generalized linear regression models. HRQoL is evaluated through the SF-12 instrument together with responses to the first item of the SF-12, self-reported health status. The SF-12 instrument generates three measures of HRQoL: the physical component summary (PCS), the mental component summary (MCS) and SF-6D utilities. Health status is captured as a self-report on a 5-point scale. Employment status is considered in terms of self-reported labor force participation, while absenteeism and presenteeism are estimated from the Work Productivity Activity Index (WPAI). Apart from a binary variable capturing the presence or absence of rheumatoid arthritis, control variables were included to capture the impact of other potential determinants of HRQoL and health status.

RESULTS

The presence of rheumatoid arthritis in urban China has a significant deficit impact on HRQoL as measured by the PCS and MCS components of the SF-12, SF-6D absolute utilities and on self-assessed health status. In the case of PCS, the deficit impact of rheumatoid arthritis is -2.289 (95%CI: -3.042 to -1.536); for MCS -1.472 (95%CI: -2.338 to -0.605) and for utilities -0.025 (95% CI: -0.036 to -0.014). In the case of health status the odds ratio for the presence of rheumatoid arthritis is 1.275 (95%CI 1.031-1.576). The presence of rheumatoid arthritis has a marked negative effect, just under 8%, on the likelihood of workforce participation. Finally, the presence of rheumatoid arthritis is associated with an increased likelihood of absenteeism and presenteeism.

LIMITATIONS

The NHWS survey has a number of limitations. As the NHWS is an internet-based survey, biases may be present due to the lack of internet penetration in the urban China population. The extent to which individuals and households have internet access is unknown. In addition, the NHWS relies upon respondents reporting they have been diagnosed with one or more specific disease states. These are not, given the nature of the survey, clinically verified. This also introduces a degree of uncertainty. Care should be taken in uncritically generalizing these results to the wider China population.

CONCLUSIONS

The burden of disease associated with self-reported, diagnosed rheumatoid arthritis in urban China is substantial. Utilizing a series of multivariate models, substantial deficits are associated not only in reported HRQoL and health status but also in respect of employment status and, for those in employment, rates of absenteeism and presenteeism.