Assessment of the Toronto Psoriatic Arthritis Screen 2 as a Screening Tool for Psoriasis.

BACKGROUND: Psoriasis is a chronic inflammatory disease affecting multiple organ systems and resulting in reduced quality of life for many patients. A screening tool would be useful, particularly in underserviced or research settings with limited access to dermatologists. The Toronto Psoriatic Arthritis Screen, version 2 (ToPAS 2) is a validated screening tool for psoriatic arthritis containing questions specific for psoriasis. OBJECTIVES: To evaluate the performance of skin-specific questions from ToPAS 2 for the diagnosis of psoriasis. METHODS: Participants aged >18 were recruited from Dermatology and Family Medicine clinics and completed the ToPAS 2 questionnaire prior to being examined by a dermatologist for psoriasis. Two scoring indexes were derived from the ToPAS 2 skin-related questions using backward selection regression models. Statistical analysis was performed using receiver operating characteristic (ROC) curves to measure their performances. RESULTS: Two hundred and fifty eight participants were recruited. 32 (12%) were diagnosed with psoriasis by dermatologist assessment. Index 1 includes all 5 skin-related questions from ToPAS 2, while Index 2 includes three of the five questions. Both indexes demonstrate high specificity (82% to 92%), sensitivity (69% to 84%), and excellent negative predictive value (NPV) (>95%) for a diagnosis of psoriasis. The overall discriminatory power of these models is 0.823 (Index 1) and 0.875 (Index 2). CONCLUSIONS: Skin-related questions from ToPAS 2 have discriminatory value in detecting psoriasis, specifically questions relating to a family history, a prior physician diagnosis of psoriasis or a rash consistent with images of plaque psoriasis. This study is a valuable step in developing a screening tool for psoriasis.

The burden of carotid artery plaques is higher in patients with psoriatic arthritis compared with those with psoriasis alone.

AIM: To compare the extent of atherosclerosis in patients with psoriatic arthritis (PsA) and patients with cutaneous psoriasis without arthritis (PsC). METHODS: In this cross-sectional study the authors compared patients with PsA with PsC patients. Psoriasis patients underwent a rheumatological assessment to exclude inflammatory arthritis. Ultrasonographic measurements of carotid total plaque area (TPA) and carotid intima-media thickness (cIMT) were performed. t Test was used to compare the imaging findings between the two groups. Multivariate linear regression analysis was used to assess the association between disease status and imaging findings after adjusting for potential confounders. RESULTS: Overall, 125 PsA and 114 PsC patients were compared. There were no significant differences in age, gender or cardiovascular risk factors between the two groups. Patients with PsA exhibited greater TPA than did PsC patients (TPA (square root of area in mm(2)) 3.33±3.34 vs 2.43±2.72, p=0.03). This difference remained statistically significant in the multivariate regression analysis after adjusting for potential confounders (p=0.03). The difference in cIMT between the groups did not achieve statistical significance (p=0.09). The following disease-related variables were associated with increase in TPA in multivariate regression analysis among PsA patients: duration of PsA (p=0.04), highest Psoriasis Area and Severity Index recorded in the first 3 years of follow-up (p=0.02) and erythrocyte sedimentation rate (p=0.005). CONCLUSIONS: PsA patients suffer from more severe subclinical atherosclerosis compared with patients with PsC. This difference is independent of traditional cardiovascular risk factors and correlates with PsA disease duration, more severe skin disease and increased inflammatory markers.

Differential human leucocyte allele association between psoriasis and psoriatic arthritis: a family-based association study.

OBJECTIVE: A recent population-based study identified several HLA alleles as conferring a risk for psoriatic arthritis (PsA) among patients with psoriasis. The authors aimed to confirm these results using a family-based association study. METHODS: PsA probands, psoriasis probands and their first-degree family members were included. All participants were evaluated for the presence of psoriasis and inflammatory arthritis. HLA-B and -C genotyping was performed. The family-based association test was used to test for differences between PsA and psoriasis patients in transmission of candidate alleles from parents to offspring. RESULTS: A total of 178 PsA and 30 psoriasis probands and 561 first degree family members were analysed. The following HLA alleles were over-transmitted to PsA compared with psoriasis: HLA-C*12 (p=0.005), HLA-B*38 (p=0.04), HLA-B*39 (p=0.03), HLA-B*27 (p=0.002). CONCLUSIONS: HLA-B*27, HLA-B*38, HLA-B*39 and HLA-C*12 alleles are potential PsA-specific genetic markers among patients with psoriasis.

The association between smoking and the development of psoriatic arthritis among psoriasis patients.

AIM: To investigate the association between smoking and psoriatic arthritis (PsA) among patients with psoriasis and its interaction with the HLA-C*06 allele. METHODS: In this exploratory case-control study, smoking status was determined at the time of the diagnosis of arthritis for PsA patients and at their first study visit for psoriasis patients, when they were confirmed not to have PsA. The proportions of patients exposed to smoking were compared in patients with PsA to those with psoriasis alone. A logistic regression model was constructed to test the independent association of smoking and PsA after adjusting for potential confounders. The statistical interaction between HLA-C*06 and smoking was tested through a regression model. RESULTS: The proportions of current and past smokers were higher in the psoriasis group compared with the PsA group (30.2% vs 23.4% and 26.7% vs 22.3%, p=0.001, respectively). On multivariate analysis being a current smoker versus a lifetime non-smoker remained inversely associated with PsA (OR 0.57, p=0.002), while past smoker versus lifetime non-smoker status was no longer significant. In a subgroup analysis, smoking remained inversely associated with PsA only among patients who were HLA-C*06 negative. Regression analysis revealed that the interaction between smoking status (ever smoked vs lifetime non-smoker) and HLA-C*06 was statistically significant (p=0.01). CONCLUSION: Smoking may be inversely associated with PsA among psoriasis patients. This association is not present among HLA-C*06-positive individuals.

Human leucocyte antigen risk alleles for psoriatic arthritis among patients with psoriasis.

UNLABELLED: Aim Genes that differentiate patients with psoriatic arthritis (PsA) from those with cutaneous psoriasis (PsC) may serve as markers for the development of PsA in patients with psoriasis. The authors aimed to identify human leucocyte antigen (HLA) alleles that are associated with the development of PsA in patients with psoriasis. METHODS: 712 adult patients with PsA, 335 adult patients with PsC and 713 healthy controls were genotyped for HLA-A, HLA-B, HLA-C, HLA-DR and HLA-DQ alleles. Differences in allelic distributions for each of the HLA loci were compared using a likelihood ratio test. Logistic regression analysis of multiple loci was performed to account for linkage disequilibrium. Haplotype information was inferred using the expectation-maximisation algorithm (given HLA-C and HLA-B genotypes) and analysed similarly. RESULTS: The following HLA alleles were found to be significantly associated with patients with PsA compared to patients with PsC in multivariate regression analysis: B*08 (OR 1.61, p=0.009), B*27 (OR 5.17, p<0.0001), B*38 (OR 1.65, p=0.026) and C*06 (OR 0.58, p=0.0002). HLA-B*27, HLA-B*38 and HLA-C*06 frequencies were also significantly higher in patients with PsA than in healthy controls (B*27: OR 3.05, p<0.0001; B*38: OR 5.9, p<0.0001; HLA-C*06: OR 1.71, p<0.0001). The following haplotypes were independently associated with PsA compared to PsC: HLA-B*18-C*07 (OR 10.1, p=0.004), HLA-B*27-C*01 (OR 41.1, p<0.0001), HLA-B*27-C*02 (OR 19.9, p<0.0001), HLA-B*38-C*12 (OR 2.9, p=0.01), HLA-B*08-C*07 (OR 2.6, p=0.004) and HLA-B*57-C*06 (OR 0.5, p=0.03). CONCLUSIONS: Certain HLA-B and HLA-C alleles confer susceptibility to PsA among patients with psoriasis and may be used to identify patients with PsC who may develop PsA.

Effect of pregnancy on ankylosing spondylitis: a case-control study.

OBJECTIVE: To evaluate the effect of pregnancy on ankylosing spondylitis (AS). METHODS: Our study aimed to determine the severity of back pain and stiffness pre-, during, and postpartum in patients with AS and controls, and corresponding extraarticular symptoms. RESULTS: Nineteen female patients with AS (35 pregnancies) and 33 controls (77 pregnancies) were studied. Improvement in pain was reported in 51% of AS patients, predominantly in the first trimester, with significant improvement in pain than stiffness. In both groups, pain worsened in later stages, likely secondary to biomechanical loading. Postpartum pain scores in AS returned to prepartum levels in general. CONCLUSION: Pregnancy does not substantially aggravate disease activity or severity in AS.

IL13 gene polymorphism is a marker for psoriatic arthritis among psoriasis patients.

AIM: To study the association between smoking and IL13 gene polymorphisms with psoriatic arthritis (PsA) and psoriasis. METHODS: The authors genotyped three groups of Caucasians: those with PsA, those with psoriasis without arthritis (PsC) and healthy controls for the rs20541 and rs848 IL13 single nucleotide polymorphisms (SNPs). An additional SNP, rs1800925, was genotyped only in the PsA and PsC groups. The differences in allelic distributions were compared by χ(2) test. The prevalence of smoking was compared between people with PsA and those with PsC. The combined effect of genotype and smoking was tested by comparing the frequencies of different combinations of rs1800925 genotype and smoking status in PsA and PsC. RESULTS: 555 PsA patients, 342 PsC patients and 217 healthy controls were included in the study. Smoking was less prevalent in patients with PsA compared with PsC (47.4% vs 59.4%, p<0.0006). rs20541*G and rs848*C alleles were associated with PsA compared with controls (OR 1.64, p=0.0005, OR 1.61, p=0.0007 respectively). The association between these alleles and PsC compared with controls was only of borderline significance (OR 1.33, p=0.06, OR 1.26, p=0.11 respectively). Two major alleles, rs1800925*C (OR 1.28, p=0.045) and rs848*C (OR 1.30, p=0.047) were increased in PsA compared with PsC. The combination of non-smoking and the genotype rs1800925*CC was associated with increased susceptibility to PsA compared with PsC. Among smokers, rs1800925*CC was not associated with PsA compared with PsC. CONCLUSIONS: IL13 gene polymorphism is associated with increased susceptibility to PsA in psoriasis patients.

Association between environmental factors and onset of psoriatic arthritis in patients with psoriasis.

OBJECTIVE: To investigate the association between potential environmental exposures and the development of psoriatic arthritis (PsA) in patients with psoriasis. METHODS: In this case-control study, the cases were patients with recent-onset PsA. The controls were psoriasis patients without arthritis. The occurrence of the following environmental exposures was recorded through a standardized questionnaire: smoking, alcohol consumption, infections, injuries, physically demanding occupational tasks, stressful life events, vaccinations, and female hormonal exposures. The association between each exposure to environmental events and disease status was assessed through logistic regression after adjustment for age, sex, education level, and duration and severity of psoriasis. RESULTS: There were 159 subjects in each group. The following exposures remained significantly associated with PsA following multivariate logistic regression: lifting cumulative loads of at least 100 pounds/hour (odds ratio [OR] 2.8, 95% confidence interval [95% CI] 1.51-5.05), infections that required antibiotics (OR 1.7, 95% CI 1.00-2.77), smoking (OR 0.6, 95% CI 0.36-0.89), and injuries (OR 2.1, 95% CI 1.11-4.01). The results were not appreciably changed with the inclusion of each of these factors in a single regression model; however, the level of significance for injuries had become borderline. No association was found between PsA and alcohol consumption, vaccination, stressful life events, and female hormonal exposures. CONCLUSION: Lifting heavy loads and infections that required antibiotics were associated with the occurrence of arthritis among patients with psoriasis. There was an inverse association between smoking and PsA. Further studies are necessary to determine whether these and other environmental factors are moderated by predisposing genetic factors.

Incidence of arthritis in a prospective cohort of psoriasis patients.

OBJECTIVE: Epidemiologic studies about the incidence of psoriatic arthritis (PsA) are limited to a few population-based studies. There are limited data regarding the incidence of PsA in patients with psoriasis. We aimed to determine the incidence of PsA among a prospective cohort of psoriasis patients. METHODS: The setting is a prospective longitudinal cohort study of psoriasis patients without arthritis. The patients are assessed annually by a rheumatologist in order to detect the onset of arthritis. We summarize the results of 4 years of followup and report the cumulative incidence of PsA from the time of entry to the study that was estimated using an event per person-years analysis and a nonparametric analysis. RESULTS: Three hundred thirteen psoriasis patients that had at least 1 year of followup were included in the analysis. The annual incidence rate was found to be 1.87 (95% confidence interval 0.71-3.03) PsA cases per 100 psoriasis patients. CONCLUSION: The incidence rate of PsA in patients with psoriasis may be higher than previously reported, particularly among patients with moderate to severe psoriasis.