A clinical and radiographic comparison of patients with psoriatic arthritis from different ethnic backgrounds.

OBJECTIVES: There are few papers concerning ethnic differences in disease expression in PsA, which may be influenced by a number of genetic, lifestyle and cultural factors. This article aims to compare clinical and radiographic phenotypes in people of South Asian (SA) and North European (NE) origin with a diagnosis of PsA. METHODS: This was a cross-sectional observational study recruiting patients of SA and NE origin from two hospitals in a well-defined area in the North of England. RESULTS: A total of 58 SA and 48 NE patients were recruited. SA patients had a more severe clinical phenotype with more tender (median 5 vs 2) and swollen (median 1 vs 0) joints, more severe enthesitis (median 3 vs 1.5), more patients with dactylitis (24% vs 8%), more severe skin disease (median PASI 2.2 vs 1) and worse disease activity as measured by the composite Psoriatic Arthritis Disease Activity Score (mean 4.5 vs 3.6). With regards to patient-completed measures, SA patients had worse impact with poorer quality of life and function (mean HAQ 0.9 vs 0.6; mean PsAQoL 10.8 vs 6.2; mean 36-item short form physical component score 33.5 vs 38.9). No significant differences in current MTX and biologics use were found. CONCLUSIONS: SA patients had a worse clinical phenotype and worse impact of disease than NE patients. Further studies are needed to confirm and explore the reasons behind these differences.

Associations between human leukocyte antigen C locus polymorphism and psoriatic arthritis in populations of European and Middle Eastern descent: a meta-analysis.

BACKGROUND: Gene-disease association between human leukocyte antigen (HLA)-C locus polymorphism and psoriatic arthritis (PsA) remains controversial. OBJECTIVE: Evaluate the relationship between HLA-C locus polymorphism and PsA in populations of European and Middle Eastern descent. SEARCH METHODS: PubMed, PMC, Elsevier and Google Scholar databases from 1980 to January 2020. The search was limited to articles in English. SELECTION CRITERIA: Case-control studies (with unrelated participants) that had allele/genotype data on the association between HLA-C locus polymorphism and PsA susceptibility. DATA COLLECTION AND ANALYSIS: Two investigators searched independently in searching the literature. Disagreements were resolved by discussion and consultation with a third researcher. The Q-Genie tool was used to assess the quality of articles. RESULTS: Twenty-five studies met the inclusion criteria. At the allelic level, three alleles were associated with an increased risk of PsA and five were associated with a reduced risk. At the phenotypic level, four alleles were associated with increased risk of PsA and three were associated with a reduced risk. At both the allelic and phenotypic levels, the results revealed that HLA-C*04 played a protective role in PsA (The pooled odds ratio [OR] is 0.66 for allelic level and 0.63 for phenotypic level), while HLA-C*02, *06 and *12 increased the risk of suffering from PsA (The pooled ORs of C*02, *06 and *12 are 2.21, 2.63 and 1.49 for allelic level, and 1.79, 2.96 and 2.25 for phenotypic level, respectively). CONCLUSION: The pooled results showed a significant association between PsA and the HLA-C gene in populations of European and Middle Eastern descent. At both the allelic and phenotypic levels, the HLA-C*02, *06 and *12 may contribute to susceptibility to PsA, while HLA-C*04 may confer a protective role against PsA. REGISTRATION: Not registered. CONFLICT OF INTEREST: None.

Factors associated with patient-physician discordance in a prospective cohort of patients with psoriatic arthritis: An Asian perspective.

OBJECTIVES: To evaluate factors associated with patient-physician discordance in a multiethnic Asian cohort of psoriatic arthritis (PsA) patients. METHODS: We used data from a prospective cohort of consecutive patients with PsA fulfilling the Classification Criteria for Psoriatic Arthritis, recruited from a single center in Singapore. Sociodemographic, clinical data and patient-reported outcomes were collected using a standardized protocol at baseline, 4 months, 8 months, 1 year, 2 years and 5 years. patient-physician discordance was defined as patient global assessment minus physician global assessment (PGA-PhGA). We evaluated variables associated with patient-physician discordance using generalized linear regression to control for within-subject effect. RESULTS: One hundred and fortytwo patients (51.4% male, 66.2% Chinese, mean [SD] age and duration of illness 51.1 [13.8] years and 27.5 [98.3] months) were recruited at baseline. Paired results for PGA and PhGA were available for 291 visits with median (interquartile range) follow-up time of 11.6 (17) months. In univariable analysis, duration of illness, fatigue, pain, tender and swollen joint count, dactylitis count, and health-related quality of life (Short Form-36) domains were significantly correlated with patient-physician discordance. In multivariable analysis, age, fatigue level, pain score were positively associated with patient-physician discordance, while swollen joint count and mental health were negatively associated with patient physician discordance. CONCLUSIONS: Increased age, higher fatigue levels, higher pain score  and poorer mental health may explain underestimation of disease activity by physicians. Physicians' overestimation of disease activity may be explained by higher swollen joint counts.

Human leukocyte antigen and demographic characteristics in Chinese patients with active peripheral type psoriatic arthritis who had inadequate response to conventional disease-modifying antirheumatic drugs in a single dermatologic clinic.

BACKGROUND: Correlation between severity of psoriasis and psoriatic arthritis (PsA) is inconsistent. Also, human leukocyte antigen (HLA)-Cw6 was found to be underrepresented in severe psoriasis who failed conventional systemic therapies, but the effect of HLA polymorphism on PsA severity needs to be confirmed. OBJECTIVES: To describe the severity of psoriasis, demographic features and HLA polymorphism among Chinese patients with active peripheral type PsA who had inadequate response to conventional disease-modifying antirheumatic drugs. METHODS: We included all patients with PsA who had at least 3 tender and swollen peripheral joints despite at least two conventional non-biologic treatments in our clinic. Demographic results were compared with global pivotal studies of biologics for PsA. HLA-Cw and HLA-DRB1 genotyping was also analyzed. RESULTS: We identified 60 patients who met our inclusion criteria. The male to female ratio was 1.31:1. The majority of patients presented with psoriasis first (81.7%). The mean interval between psoriasis and PsA was 7.2 ± 8.1 years (mean ± SD). The baseline number of tender and swollen joints was 14.9 ± 10.7 and 11.3 ±10.2, respectively. In total, 41.7% subjects had more than 3% body surface area involvement of psoriasis. Genotyping of HLA-Cw and HLA-DRB1 was performed in 47 subjects. HLA-Cw*0702 was the most frequent allele (29.8%), followed by HLA-Cw*01 (26.6%). The frequency of HLA-Cw*0602 allele was similar to normal population. The most frequent HLA-DRB1 allele was HLA-DRB1*04 (20.2%), followed by HLA-DRB1*08 (16.0%). No cases carrying HLA-DRB1*13 were detected. CONCLUSIONS: Compared with Western population, our patients had less psoriasis and PsA burden. The frequencies of HLA-Cw*06, HLA-Cw*12, and HLA-DRB1*07 were not increased. In contrast, HLA-Cw*0702 and HLA-DRB1*08 allele frequencies were increased compared with psoriasis patients and normal population in Taiwan. Future studies are still needed to characterize the demographic and genetic features of high need PsA patients.

Effect of ethnicity on disease activity and physical function in psoriatic arthritis in a multiethnic Asian population.

Geographic differences in manifestation of psoriatic arthritis (PsA) could be related to differences in genetic or environmental factors. We aimed to compare the disease activity and functional status using validated outcome measures among patients with PsA of different ethnicities living in the same environment. We performed a cross-sectional study on consecutive patients with PsA classified by the Classification Criteria for Psoriatic Arthritis (CASPAR) criteria from a single center. Sociodemographic data, clinical variables, and patient-reported outcomes were collected using a standardized protocol. Disease activities were assessed by validated composite scores: clinical Disease Activity Index for Psoriatic Arthritis (cDAPSA), Composite Psoriatic Disease Activity Index (CPDAI), and minimal disease activity (MDA). Physical function was assessed with Health Assessment Questionnaire (HAQ) and the Medical Outcome Study Short-Form 36 (SF36) physical function subscales. Linear regression analyses were performed to identify variables associated with disease activities and physical function. Ninety-eight patients (51.5%, men) with mean (±SD) age and duration of PsA of 51.5 ± 13.8 and 5.5 ± 8.4 years were recruited. Indian was overrepresented compared with the national distribution of ethnicities. Compared to Chinese, Indian patients were more likely to be using biological therapies, have higher tender joint count, and worse enthesitis. Higher proportion of Indians had higher disease activity categories measured by cDAPSA, CPDAI, and MDA and had poorer physical function. In the multivariable analysis, ethnicity was significantly associated with HAQ and SF36-PF. Compared to Chinese, Indians with PsA living in the same environment had worse disease activity and physical function measured by validated outcomes.

Psoriatic arthritis in Japan: difference in clinical features and approach to precision medicine.

Psoriatic arthritis (PsA) is a chronic and progressive inflammatory arthritis that is common among patients with psoriasis, often resulting in permanent damage of joints and spines. Recent report indicates that the prevalence of PsA among Japanese patients with psoriasis is 14.3%, which is similar or slightly less than that of PsA in Caucasian, 6-42%. Skin disorders precede arthritis in 60-80% of Japanese patients with PsA and oligoarthritis or polyarthritis is the dominant pattern of them. The genotypic backgrounds appear different among Japanese and Caucasians. Biological DMARDs (bDMARDs) targeting cytokines IL-12/IL-23, TNF and IL-17 involved in the pathogenesis of PsA, have been emerging for the treatment. Although background characteristics are various among studies, anti-IL-17 seemed to be slightly better in Japanese than in global, whereas anti-IL-12/23 and anti-TNF tended to be better in global than in Japanese. Because PsA is a clinically heterogeneous disorder, we have tried to classify PsA by phenotypic differences of peripheral lymphocyte using 8-color flow cytometry and found that PsA can be divided to four types, activated Th17-dominant, Th1-dominant, both of them and neither of them. We currently try to treat patients with different bDMARDs based on the difference of lymphocyte phenotype, which may lead to precision medicine of PsA.

Predictors of functional deterioration in Chinese patients with psoriatic arthritis: a longitudinal study.

BACKGROUND: Psoriatic arthritis (PsA) disease activities at baseline may determine physical function over time. There is no longitudinal data on course of physical function in PsA patients from Asia. We aim to describe variables associated with a deterioration of physical function in PsA in Chinese over a 6-year period. METHODS: 125 consecutive patients with PsA fulfilled the CASPAR criteria from a rheumatology outpatient center were recruited to give sociodemographic and clinical data in 2006 to 2008. Follow up interviews were conducted in 2012 to 2013 to assess physical function using Health Assessment Questionnaire (HAQ). Regression models were constructed to determine baseline variables that predict physical function on follow up. RESULTS: A total of 97 patients completed the follow up survey, with mean follow up time of 6.2 (±0.7) years, response rate 77.6%. PsA patients had poor physical function and health related quality of life (HRQoL) compared to normal population. There were 33% who improved in disability status and 41.2% had persistent minimal disability by HAQ categories (HAQ 0-0.49) over time. There were 14.4% of the patients who had persistent moderate disability (HAQ 0.5-1.50) and 10.3% had deterioration in disability status. There were 17.5% of patients who had deterioration in physical function as defined by an increment of HAQ score of more than 0.2 at follow up survey. Age, physical function at baseline and the number of damaged joint were significantly related HAQ at follow up. CONCLUSION: Chinese patients with PsA had had poor physical function and quality of life. One fifth of patient experienced deterioration of physical function over time. Joint damage and baseline physical function were important factors associated with poor physical function in PsA over time.

Associations between the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism and susceptibility to psoriasis and psoriatic arthritis: a meta-analysis.

The aim of this study was to assess whether the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism is associated with the susceptibility to psoriasis and psoriatic arthritis (PsA). A meta-analysis was conducted to establish the association between the MICA-TM A9 allele and psoriasis and PsA in the general population and each ethnic group. Ten studies (6 psoriasis, 4 PsA) involving 2,002 cases and 1,933 controls were included in this meta-analysis. The Asian controls showed the lowest A9 allele prevalence (16.6%), whereas the European controls had the highest allele prevalence (33.3%). Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population, which included the psoriasis and PsA cases (OR 1.703; 95% CI 1.301-2.229; p = 1.0 × 10(-5)). We further divided the entire study population into the psoriasis and PsA groups. Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population (OR 1.427, 95% CI 1.021-1.994; p = 0.037) and Asians (OR 1.264; 95% CI 1.014-1.576; p = 0.037). A significant association was found between the MICA-TM A9 allele and PsA (OR 2.227; 95% CI 1.462-3.393; p = 1.9 × 10(-5)) and Europeans (OR 2.039; 95% CI 1.285-3.235; p = 0.002). This meta-analysis showed that the MICA-TM A9 allele is associated with psoriasis susceptibility in Asian populations and that the MICA-TM A9 allele is associated with a PsA risk in Europeans.

Cross-sectional study assessing family members of psoriatic arthritis patients affected by the same disease: differences between Caucasian, South Asian and Afro-Caribbean populations living in the same geographic region.

AIM: To determine the likelihood of an individual developing psoriatic arthritis (PsA) if they have a relative diagnosed with this disease, and to compare rates among different ethnic groups living in the same geographic region. METHOD: Family histories of patients with PsA were assessed using a semi-structured questionnaire. RESULTS: Data on family members of patients with SpA were collected for 151 patients (46.6%) of the total cohort of 324. A total of 146 patients in the SpA cohort had PsA (45%) and 88 of these patients (60.2%) also had relatives with PsA. Psoriatic arthritis was seen more commonly in Caucasians (n = 88, 58.3%) than in South Asians (n = 28, 18.5%; P < 0.001) or African/Afro-Caribbean (n = 11, 7.3%; P < 0.002) individuals. Caucasians more commonly had relatives affected by the disease (49/78, 62.8%) than in South Asians (16/33, 48.4%; P < 0.034). CONCLUSIONS: Psoriatic arthritis was more common in Caucasian than in South Asian patients. The relatives of Caucasian patients were also more likely to have PsA compared with South Asian patients. Among South Asian patients, the relatives of Pakistani patients were significantly more likely to have PsA compared with other South Asian populations. Patients with a relative with PsA were three times more likely to develop PsA, with an increased likelihood for Pakistani individuals (by a factor of 5.29) compared with other South Asians (2.88) and Caucasians (4.32).

A hot spot for systemic lupus erythematosus, but not for psoriatic arthritis, identified by spatial analysis suggests an interaction between ethnicity and place of residence.

OBJECTIVE: To describe the spatial distribution of incident cases of systemic lupus erythematosus (SLE) using geographic information systems (GIS). METHODS: Spatial analyses were carried out on 890 SLE patients and 541 psoriatic arthritis (PsA) patients (controls). Age- and sex-adjusted rates for SLE/PsA for each census tract were calculated using denominator population values from the Canadian census. Spatial variations in relative risk were estimated by modeling risk as the product of a time effect, an age effect, and a spatially autocorrelated risk surface to identify hot spots. Patients within the detected hot spot were compared to those outside the hot spot to identify explanatory factors. RESULTS: SLE patients were predominantly female (87.75%) and the incidence rate was highest among those 15-19 years of age (2.4 cases/100,000 person-years). In an SLE hot spot containing 59 patients, 100% of the patients were female and 49.1% (n = 29) were Caucasian, while outside of the hot spot, 86.9% (n = 722) of the patients were female and 68.4% (n = 568) were Caucasian. The proportion of cases of Chinese ethnicity was significantly greater within the hot spot. An interaction was found between Chinese ethnicity and residence within the hot spot, with the risk of SLE to the Chinese population found to be twice the risk to the non-Chinese population. CONCLUSION: GIS was used to map SLE cases and a hot spot was identified after adjustment for age and sex. Ethnicity by itself did not confer an increased risk of SLE, but the interaction of ethnicity with location of residence significantly increased the risk of SLE.

Phenotypic and clinical differences between Caucasian and South Asian patients with psoriatic arthritis living in North East London.

To test for demographic and clinical differences between Caucasian and South Asian patients with psoriatic arthritis (PsA) living in the same environment and for differences between sexes. The demographic characteristics of patients attending outpatient clinics were obtained using a semi-structured questionnaire. Clinical parameters included disease activity (Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), erythrocyte sedimentation rate (ESR), C-reactive protein), function (Bath Ankylosing Spondylitis Functional Index (BASFI)) and visual analogue scale (VAS) scores for well-being and night pain (10 cm, where 10 = worst possible response). The first symptom experienced at disease onset and the main symptoms during the disease course were recorded in the questionnaire. A total of 217 patents were assessed of whom 151 were Caucasians and 66 were Asians. South Asian patients were significantly younger [(mean) 45.9 years [(SD)(±11.4)] for Asians and 53.1 years (±14.2) for Caucasians (p < 0.005)] and were diagnosed at an earlier age [40.7 years (±11.7) for Asians and 46.7 years (±15.8) for Caucasians (p < 0.05)] compared to Caucasians patients. Asian females with PsA had worse disease in terms of activity (ESR = 23.9 mmHg/h; BASDAI = 6.7), function (BASFI = 5.5), night pain (7.1 on VAS) and well-being (6.6 on VAS) compared with Asian males (13.2 mmHg/h, 5.3, 3.6, 4.1, 4.6, respectively) or Caucasian males and females (15.8 mmHg/h, 5.9, 5.3, 5.4, 5.4; 18.9 mmHg/h, 6.1, 6.1, 5.3, 5.8, respectively). There were no significant differences in symptoms at disease onset or the main symptoms during the disease course between Caucasian and Asian patients, although there was a trend towards more frequent enthesitis in Asian females during the course of disease suggested by pain with pressure compared to Asian males. South Asian patients may develop PsA earlier in life than Caucasian patients do, but their clinical characteristics are generally similar. Asian females with PsA have worse disease activity, function, night pain and well-being than Asian males and Caucasian males and females.

Psoriasis and psoriatic arthritis in Peruvian aborigines: a report from the GRAPPA 2011 annual meeting.

OBJECTIVE: To determine the presence of psoriasis and psoriatic arthritis (PsA) in aboriginal people living in the Andean Mountains of Peru. METHODS: Consecutive patients with psoriasis and PsA attending an arthritis clinic in Juliaca, Puno, Peru, located 3824 m above sea level were examined. The CASPAR (ClASsification of Psoriatic ARthritis) criteria were used for classification of PsA. Diagnosis of psoriasis was confirmed by a dermatologist. RESULTS: Seventeen patients [11 (65%) men and 6 (35%) women] fulfilled classification criteria for PsA; one patient was of European ancestry and is not included in this report. Of the 16 aboriginal patients in this report, 5 were natives of Quechua ancestry and one was native Aymara. At the time of their first clinic visit, no native patient with PsA had a family history of psoriasis or PsA, and all patients exhibited an established disease of long duration and severity. Methotrexate was the drug of choice for all patients; 2 patients are currently receiving biological therapy. CONCLUSION: Contrary to what has been reported in the literature, both psoriasis and PsA are present in aboriginal people from the Andean Mountains of Peru. More studies are needed to further define the phenotype of these disorders, as well as the pathogenetic role of genetic and environmental factors.

Ethnic influence in clinical and functional measures of Brazilian patients with spondyloarthritis.

OBJECTIVE: Spondyloarthritides (SpA) can present different disease spectra according to ethnic background. The Brazilian Registry of Spondyloarthritis (RBE) is a nationwide registry that comprises a large databank on clinical, functional, and treatment data on Brazilian patients with SpA. The aim of our study was to analyze the influence of ethnic background in SpA disease patterns in a large series of Brazilian patients. METHODS: A common protocol of investigation was prospectively applied to 1318 SpA patients in 29 centers distributed through the main geographical regions in Brazil. The group comprised whites (65%), African Brazilians (31.3%), and people of mixed origins (3.7%). Clinical and demographic variables and various disease index scores were compiled. Ankylosing spondylitis (AS) was the most frequent disease in the group (65.1%); others were psoriatic arthritis (18.3%), undifferentiated SpA (6.8%), enteropathic arthritis (3.7%), and reactive arthritis (3.4%). RESULTS: White patients were significantly associated with psoriasis (p = 0.002), positive HLA-B27 (p = 0.014), and use of corticosteroids (p < 0.0001). Hip involvement (p = 0.02), axial inflammatory pain (p = 0.04), and radiographic sacroiliitis (p = 0.025) were associated with African Brazilian descent. Sex distribution, family history, and presence of peripheral arthritis, uveitis, dactylitis, urethritis, and inflammatory bowel disease were similar in the 3 groups, as well as age at disease onset, time from first symptom until diagnosis, and use of anti-tumor necrosis factor-α agents (p > 0.05). Schober test and thoracic expansion were similar in the 3 groups, whereas African Brazilians had higher Maastricht Ankylosing Spondylitis Enthesitis Scores (p = 0.005) and decreased lateral lumbar flexion (p = 0.003), while whites had a higher occiput-to-wall distance (p = 0.02). African Brazilians reported a worse patient global assessment of disease (p = 0.011). Other index scores and prevalence of work incapacity were similar in the 3 groups, although African Brazilians had worse performance in the Ankylosing Spondylitis Quality of Life questionnaire (p < 0.001). CONCLUSION: Ethnic background is associated with distinct clinical aspects of SpA in Brazilian patients. African Brazilian patients with SpA have a poorer quality of life and report worse disease compared to whites.

Tumor necrosis factor promoter polymorphism TNF*-857 is a risk allele for psoriatic arthritis independent of the PSORS1 locus.

OBJECTIVE: The strongest susceptibility locus of psoriatic arthritis (PsA) is within the major histocompatibility complex (MHC) region (psoriasis susceptibility region 1, or PSORS1), and HLA-Cw*06:02 has been reported as the PSORS1 susceptibility allele. Non-HLA genes within the MHC region have also been implicated in PsA, but because of the strong linkage disequilibrium at chromosome 6p21, it is difficult to make a distinction between susceptibility alleles and linked markers. Recent studies have demonstrated that the association between PsA and the tumor necrosis factor (TNF) promoter polymorphism TNF*-857 is independent of PSORS1. The aim of this study was to replicate the independent association of TNF*-857 in patients with PsA. METHODS: A total of 909 patients with PsA and 1,315 healthy controls originating from the UK, Germany, and Italy were typed for TNF*-857 and for the estimated risk alleles of HLA-Cw*06:02. RESULTS: Overall, the results of genotyping in these 3 case-control cohorts replicated the finding that the frequency of carriers of TNF*-857 TT/CT who were negative for the PSORS1 risk allele was significantly higher among patients with PsA compared with control subjects (30% versus 21%; P = 9.17 × 10(-5)). CONCLUSION: The results of this collaborative study indicate that TNF*-857T is a susceptibility allele for PsA independent of the PSORS1 allele.

Incidence and prevalence of psoriatic arthritis in Buenos Aires, Argentina: a 6-year health management organization-based study.

OBJECTIVES: Studies regarding epidemiology of PsA are lacking in Latin America. We estimated the incidence and prevalence of PsA in a University Hospital-based Health Management Organization in Buenos Aires [Hospital Italiano Medical Care Program (HIMCP)]. POPULATION: for incidence calculation, the population at risk was all adult members of the HIMCP, with continuous affiliation for at least 1 year from January 2000 to January 2006. Each person was followed until he/she voluntarily left the HIMCP, death or finalization of the study (final dates) contributing time at risk since January 2000 or enrolment date (whichever occurred later) to that final date. Case ascertainment: medical records of all patients with the problem psoriasis and/or PsA in the HIMCP problem-oriented computer-based patient record system, or registered in rheumatologists and/or dermatologists databases, were revised. Patients fulfilling CASPAR criteria were included. STATISTICAL ANALYSIS: incidence rate (IR) was calculated with 95% CIs. Cumulative prevalence was estimated on 1 January 2006 (denominator population ==88,112). RESULTS: In the study period, 138,288 persons contributed a total of 558,878 person-years, of whom 35 developed PsA (IR 6.26; 95% CI 4.2, 8.3 cases per 100,000 person-years). There were 12 females: IR 3.64 (95% CI 1.6, 5.7) cases per 100,000 person-years; and 23 males: IR 10.02 (95% CI 5.9, 14.1) cases per 100,000 person-years. On 1 January 2006, 65 prevalent cases were identified: prevalence 74 (95% CI 57, 94) cases per 100,000 members. CONCLUSIONS: The incidence and prevalence of PsA in this Latin American country was similar to that reported in other studies from Europe and the USA.

Risk factors associated with having psoriatic arthritis in patients with cutaneous psoriasis.

The aim of this study was to determine if the following characteristics were associated with the presence of psoriatic arthritis in a sample of psoriasis patients: race, family history of psoriasis and psoriatic arthritis, age of onset of psoriasis, smoking, alcohol consumption and the maximum body surface area (BSA) affected by psoriasis. This was a case-control study involving 400 psoriasis patients who attended the Psoriasis and Photo-medicine clinic in the National Skin Center of Singapore over a 1-year period. Cases were psoriasis patients with psoriatic arthritis while controls were psoriasis patients without psoriatic arthritis. The diagnosis of psoriatic arthritis was made by rheumatologists and participants completed a self-administered standardized questionnaire. The maximum BSA involved was determined from the case notes. Psoriatic arthritis was not significantly associated with sex, race, age of onset of psoriasis, a family history of psoriasis, smoking and alcohol consumption but was significantly associated with a family history of psoriatic arthritis (P < 0.001) and the maximum body surface involved (P = 0.05). Using multivariate analysis to control for variables, the presence of psoriatic arthritis was significantly associated with a family history of psoriatic arthritis (odds ratio [OR] = 20.5; 95% confidence interval [CI] = 2.49-169.10) and the maximum BSA involved (OR = 2.52; 95% CI = 1.33-4.75). Indian psoriatic patients were more likely to have psoriatic arthritis compared to the other races. A family history of psoriatic arthritis and a greater maximum body surface involved may be associated with having psoriatic arthritis in this study population of psoriasis patients.

Evaluation of the CASPAR criteria for psoriatic arthritis in the Chinese population.

OBJECTIVE: To evaluate and validate the Classification of Psoriatic Arthritis (CASPAR) criteria for PsA in a Chinese population. METHODS: Data were collected prospectively from consecutive Han Chinese clinic attendees with PsA and other chronic inflammatory arthritis. Subjects were classified according to Moll and Wright, European Spondyloarthropathy Study Group (ESSG) criteria for PsA, Vasey and Espinoza or CASPAR criteria. Sensitivity and specificity of each set of criteria were compared with the expert clinical diagnosis. Latent class analysis was used to calculate accuracy of criteria and confirm validity. RESULTS: A total of 108 (53 males and 55 females) subjects with PsA were recruited. Mean (s.d.) age and duration of illness were 48.4 (12.0) and 9.55 (7.66) years, respectively. Data were compared with 195 controls with RA (n = 154) and AS (n = 41). The ESSG criteria have the lowest sensitivity, followed by the Moll and Wright criteria. The sensitivity and specificity for the CASPAR criteria were 98.2 and 99.5%, respectively, which is similar to reported values in European populations. The latent class model agreed closely with the clinical criteria. CONCLUSIONS: The CASPAR criteria performed well in a Chinese population, which is very different from the populations for which they were developed. The CASPAR criteria have higher sensitivity in classifying PsA.

Anti-cyclic citrullinated peptide antibodies and IL-23p19 in psoriatic arthritis.

BACKGROUND: Anti-cyclic citrullinated peptide antibodies (anti-CCP) are reported to be found in 5-13% of patients with psoriatic arthritis (PsA). However, whether anti-CCP-positive PsA patients and rheumatoid arthritis (RA) patients have a similar pathophysiological background still remains uncertain. OBJECTIVE: To determine the prevalence of anti-CCP antibodies in patients with PsA and characterize these anti-CCP-positive patients of PsA. METHODS: We measured the serum levels of the anti-CCP antibodies in patients with PsA (n=16), psoriasis (n=15), RA (n=9) and healthy controls (n=11). Serum levels of rheumatoid factor (RF), matrix metalloproteinase-3 (MMP-3), cartilage oligomeric matrix protein (COMP), interleukin (IL)-23p19 and IL-12p40 were also measured in all the samples. RESULTS: Two of the 16 PsA patients (13%) were positive for anti-CCP antibodies with high titers of RF. However, the serum IL-23p19 levels were two orders of magnitude higher in the anti-CCP-positive PsA patients as compared with those in the RA patients and anti-CCP-negative PsA patients. No significant elevation of the serum levels of MMP-3, COMP and IL-12p40 was found in these patients. CONCLUSION: Thirteen percent of the PsA patients were positive for anti-CCP. These patients do not fulfill the American College of Rheumatology (ACR) classification criteria for RA so far. Furthermore, they showed the typical clinical features of PsA rather than those of RA. Although anti-CCP-positive PsA patients may possibly be have a risk of developing RA, we propose that these patients be classified, for the moment, into a independent subtype of PsA, as a different entity from RA.

Human leukocyte antigen and clinical and demographic characteristics in psoriatic arthritis and psoriasis in Chinese patients.

OBJECTIVE: Psoriasis and psoriatic arthritis (PsA) are interrelated disorders. To date, no study has compared the differences of genes between patients with PsA and psoriasis and healthy controls in a Chinese population. We conducted a retrospective study to determine the human leukocyte antigen (HLA) -A, -B, -Cw, -DR, and -DQ alleles in Chinese patients with PsA and psoriasis. METHODS: HLA studies were performed using polymerase chain reaction sequence-specific oligonucleotide (PCR-SSO) genotyping methods in 91 patients with PsA and 80 with psoriasis and 75 controls. Age at disease onset, sex, disease duration, enthesitis, and uveitis were also analyzed. RESULTS: Among the patients with PsA and psoriasis, the frequency of HLA-B27 was significantly higher in PsA and HLA-A*30, -Cw*06, -DR*07 in psoriasis compared with controls. In contrast, HLA-B*58 was more common in controls than in PsA and psoriasis groups, and the prevalence of HLA-DR*17 was significantly higher in controls than in those with psoriasis. Comparing PsA and psoriasis, the prevalence of HLA-B*27 and HLA-Cw*12 were more common in PsA patients, while the prevalence of HLA-DR*07 was higher in those with psoriasis (p < 0.05). Among PsA patients, the association between HLA-B*27 and axial joint involvement and uveitis was significant (p < 0.05). CONCLUSION: Certain HLA alleles are found in Chinese patients with psoriasis (HLA-A*30, -Cw*06, -DR*07) and PsA (HLA-B*27). Psoriasis patients with the HLA-B*27 and/or -Cw*12 may have higher risk of developing PsA. Ours is the first study to assess the genetic role of HLA in patients with psoriasis and PsA in a Chinese population.