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.

Identification of a Single Nucleotide Polymorphism in NFKBIA with Different Effects on Psoriatic Arthritis and Cutaneous Psoriasis in China.

Genome-wide association studies have recently identified a number of non-major histocompatibility complex regions associated with psoriatic arthritis. However, data on Chinese patients with psoriatic arthritis and the differences between psoriatic arthritis and cutaneous psoriasis are limited. This study genotyped 12 single nucleotide polymorphisms in 379 patients with psoriatic arthritis, 376 with cutaneous psoriasis, and 760 healthy controls using Sequenom's Mass ARRAY system. The aim of the study was to expand the database for psoriatic arthritis and cutaneous psoriasis, and develop a genetic prediction system for the early diagnosis of psoriatic arthritis in the Chinese population. One variant in NFKBIA, rs12883343, had a significantly different association with psoriatic arthritis than with cutaneous psoriasis (p = 4.93×10-10, odds ratio 2.371). This suggests that there are differences in the pathogenesis of psoriatic arthritis and cutaneous psoriasis.

Lipid management among individuals with inflammatory arthritis in the national REasons for Geographic And Racial Differences in Stroke (REGARDS) cohort.

Objective Hyperlipidemia guidelines do not currently identify inflammatory arthritis (IA) as a cardiovascular disease (CVD) risk factor. We compared hyperlipidemia treatment of individuals with and without IA (rheumatoid arthritis, psoriatic arthritis, or ankylosing spondylitis) in a large national cohort. Methods Participants from the REasons for Geographic And Racial Differences in Stroke (REGARDS) study were classified as having IA (without diabetes or hypertension); diabetes (but no IA); hypertension (but no diabetes or IA); or no IA, diabetes, or hypertension. Multivariable logistic regression models examined the odds of medical treatment among those with hyperlipidemia. Results Thirty-nine participants had IA, 5423 had diabetes, 7534 had hypertension, and 5288 had no diabetes, hypertension, or IA. The fully adjusted odds of treatment were similar between participants with IA and those without IA, hypertension, or diabetes. Participants with diabetes and no IA and participants with hypertension and no IA were twice as likely to be treated for hyperlipidemia as those without IA, diabetes, or hypertension. Conclusion Despite their higher CVD risk, patients with IA were as likely to be treated for hyperlipidemia as those without diabetes, hypertension, or IA. Lipid guidelines should identify IA as a CVD risk factor to improve CVD risk optimization in IA.

Inflammatory Arthritis Prevalence and Health Services Use in the First Nations and Non-First Nations Populations of Alberta, Canada.

OBJECTIVE: To estimate prevalence of rheumatoid arthritis (RA), ankylosing spondylitis (AS), psoriatic disease (PsD), and crystal-related arthritis and health care use for inflammatory arthritis in First Nations and non-First Nations patients in Alberta, Canada. METHODS: Population-based cohorts of adults with RA, AS, PsD, and crystal-related arthritis were defined, with First Nations determination by premium payer status, to estimate prevalence rates. Rates of outpatient primary care, specialist visits, and hospitalizations (all-cause, inflammatory-arthritis specific) were estimated. RESULTS: RA affected 3 times as many First Nations residents compared to non-First Nations residents (standardized rate ratio [SRR] 3.2, 95% confidence interval [95% CI] 2.9-3.4). AS and PsD were more prevalent in First Nations (AS 0.6 per 100 residents; SRR 2.7, 95% CI 2.3-3.2 and PsD 0.3 per 100 residents; SRR 1.5, 95% CI 1.3-1.9), whereas crystal-related arthritis was less prevalent (SRR 0.7, 95% CI 0.6-0.7). First Nations patients were more likely to have primary care visits (SRR 1.7, 95% CI 1.6-1.8) and less likely to have specialist visits (SRR 0.6, 95% CI 0.6-0.7) for RA relative to non-First Nations individuals. In PsD and crystal-related arthritis, First Nations people had higher rates of cause-specific hospitalizations. CONCLUSION: The estimated prevalence of RA, AS, and PsD was higher in the First Nations population, while crystal-related arthritis was less prevalent compared to the non-First Nations population. First Nations people were more likely to see primary care physicians and were less likely to see specialists for inflammatory arthritis care.

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.

Epidemiology of psoriatic disease and current treatment patterns from 2003 to 2013: A nationwide, population-based observational study in Taiwan.

BACKGROUND: Recent global data show an increasing prevalence of psoriasis and psoriatic arthritis in western countries. OBJECTIVE: The current study analyzed the trend of prevalence rates of psoriasis and psoriatic arthritis in Taiwan and examined biologic prescription patterns by different specialties. METHODS: Data were accessed from the national payer National Health Insurance Research Database in Taiwan. This study protocol was approved by Joint Institutional Review Board established by Medical Research Ethics Foundation (No 13-S-001). RESULTS: Between 2003 and 2013, the prevalence of psoriasis and psoriatic arthritis increased by 41% (from 15.54 to 21.90 per 10,000 population) and 191% (from 0.45 to 1.31 per 10,000 population), respectively, while the prevalence of psoriatic arthritis among patients with psoriatic disease increased from 6.3% to 12.7%. Dermatologists are the main caregivers for patients with psoriasis and psoriatic arthritis; however, data suggest a decreasing trend in the proportion of dermatologists for psoriasis patients from 24.7% between 2003 and 2008 to 10.74% between 2008 and 2013, with a corresponding decrease in dermatologists for psoriatic arthritis patients from 62.30% to 44.65% during the same periods, respectively. In 2013, of the 51,191 patients with psoriasis, only 596 (1.16%) received biologics (73.3% by dermatologists and 25.8% by rheumatologists), while 1120 of the 7470 (14.99%) psoriatic arthritis patients received biologics (72.8% by rheumatologists and 22.3% by dermatologists). The proportion of biologics use was 1.12% and 7.75% among all patients with only psoriasis and 8.01% and 26.70% among all patients with psoriatic arthritis seen by dermatologists and rheumatologists, respectively. CONCLUSION: The prevalence of psoriasis and psoriatic arthritis is increasing in Taiwan. The use of biologics in patients with psoriatic arthritis was comparable to that reported in previous studies in the United States and Europe; however, the use of biologics remained low in patients with psoriasis in Taiwan.

Psoriasis and psoriatic arthritis in African-American patients--the need to measure disease burden.

Gaps in knowledge exist regarding the clinical characteristics of psoriatic disease in ethnic minority patients. We evaluated validated clinical disease measures of psoriasis and psoriatic arthritis in African-American and Caucasian patients. Adult outpatients with confirmed diagnoses of psoriasis and psoriatic arthritis and seen at four urban academic institutions were eligible for evaluation. Validated patient and physician-reported disease outcome parameters, quality of life measures of psoriasis and psoriatic arthritis, and frequencies of systemic immunosuppressive therapies and patient comorbidities were documented. Psoriatic arthritis was less frequent in African-Americans compared to Caucasians (30 vs. 64.5 %, respectively, p < 0.001); however, African-Americans had more severe skin involvement [Psoriasis Area and Severity Index 8.4 (10.0) vs. Caucasians 5.5 (6.4), p = 0.06], with greater psychological impact and impaired quality of life. Use of biologic therapies was greater in Caucasian patients (46.2 vs. 13.3 % in African-Americans, p < 0.0001); yet, only one in four patients of the study cohort achieved minimal disease activity. Comorbidity was not associated with frequency of immunosuppressive drug use. In order to achieve a target of low disease activity and to reduce ethnic disparities in the care of psoriatic disease, the routine application of measures of disease status is needed.

Introduction to statistical modelling 2: categorical variables and interactions in linear regression.

In the first article in this series we explored the use of linear regression to predict an outcome variable from a number of predictive factors. It assumed that the predictive factors were measured on an interval scale. However, this article shows how categorical variables can also be included in a linear regression model, enabling predictions to be made separately for different groups and allowing for testing the hypothesis that the outcome differs between groups. The use of interaction terms to measure whether the effect of a particular predictor variable differs between groups is also explained. An alternative approach to testing the difference between groups of the effect of a given predictor, which consists of measuring the effect in each group separately and seeing whether the statistical significance differs between the groups, is shown to be misleading.

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.

Seronegative arthritis in Latin America: a current review.

In many Latin American countries seronegative arthritis, especially the spondyloarthritides (SpA), is commonly characterized by associated axial and peripheral involvement. In this article, the authors review the ethnic distribution of the population and the different SpA in 10 Latin American countries, and the main characteristics of the Ibero-American Registry of Spondyloarthropathies (RESPONDIA) compared with other international registries. The peripheral component of SpA is more frequent in mixed-race populations, whereas psoriatic arthritis is significantly more frequent in countries with predominantly white populations.

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.

Undifferentiated spondyloarthritis in a heterogeneous Brazilian population: an eight-year follow-up study.

The aim of the present study was to describe the outcomes of Brazilian patients with undifferentiated spondyloarthritis during an eight-year follow-up period. Patients fulfilling the European Spondyloarthritis (SpA) Study Group Classification Criteria were enrolled. Forty patients were seen at baseline, and 36 participated in the follow-up study. Twenty-three (58%) were female, and there were 24 (60%) African Brazilians enrolled. HLA-B27 was positive in 18 (45%) patients. At disease onset, the first presenting symptoms were pure peripheral manifestations in 26 (72.2%) patients. After the study period, mixed disease (axial + peripheral) predominated occurring in 25 (69.4%) patients. The Assessment of SpA International society (ASAS) classification criteria for axial SpA were fulfilled by 77% of patients, and the ASAS criteria for peripheral SpA were fulfilled by 59% of patients. After 2.5 years, 6 (16.7%) of the 36 patients fulfilled the modified New York Criteria for ankylosing spondylitis and 1 (2.7%) progressed to psoriatic arthritis. A total of 10 (27.8%) patients progressed to definite SpA during the eight-year study period. Buttock pain (p = 0.006, OR 10.55; 95% CI 2.00-65.90) and low-grade radiographic sacroiliitis (p = 0.025, OR = 11.50; 95% CI 1.33-83.39) at baseline were associated with definite SpA. Thus, in this Brazilian cohort, which had a predominance of female African-Brazilian patients, prevalent peripheral onset symptoms were followed by a high frequency of axial manifestations during the follow-up period. Evidence of clinical or radiological sacroiliitis was associated with progression to definite SpA.

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).