Validity of clinical psoriatic arthritis diagnoses made by rheumatologists in the Swedish National Patient Register.

OBJECTIVES: : Knowledge of the correspondence between clinical ICD diagnoses and classification criteria fulfilment is crucial to interpret studies identifying cases via ICD codes. We assessed the degree to which patients registered with ICD-10 diagnoses of psoriatic arthritis (PsA) in the Swedish National Patient Register (NPR) fulfil established PsA classification criteria. METHOD: Four hundred patients with at least one outpatient visit to one of five rheumatology or internal medicine departments (three university/two county departments across Sweden) in 2013-2015, with a main ICD-10 diagnosis of PsA (L40.5, M07.0-M07.3), were randomly selected (80 cases/site). Through a structured medical record review, positive predictive values (PPVs) for fulfilment of the following classification criteria were assessed: CASPAR, Moll and Wright, Vasey and Espinoza, and modified ESSG criteria for PsA. A subset analysis regarding CASPAR fulfilment was also performed among cases with available rheumatoid factor and peripheral X-ray status (central CASPAR items; n = 227). RESULTS: Of the 400 patients with a main ICD-10 diagnosis of PsA, 343 (86%) fulfilled at least one of the four PsA classification criteria. PPVs for the different criteria were: CASPAR 69% (82% in the subset analysis), Moll and Wright 51%, Vasey and Espinoza 76%, and modified ESSG 64%. Overall, only 6.5% of the 400 PsA diagnoses were judged as clearly incorrect by the medical record reviewers. CONCLUSION: The validity of rheumatologist-made, clinical ICD-10 diagnoses for PsA in the Swedish NPR is good, with PPVs of 69-82% for CASPAR fulfilment and 86% for meeting any established PsA classification criteria.

Association between inflammasome-related polymorphisms and psoriatic arthritis.

Objective: Psoriatic arthritis (PsA) is a heterogeneous inflammatory disease associated with psoriasis. Underlying genetic factors are considered important for disease expression and prognosis of PsA. Interleukin-1ß-regulating protein complexes called inflammasomes are associated with several inflammatory diseases, e.g. rheumatoid arthritis and psoriasis. The aim was to determine whether inflammasome-related genetic variation is associated with PsA susceptibility or different disease phenotypes.Method: DNA from 724 patients with PsA and 587 population-based controls from northern Sweden was analysed for single-nucleotide polymorphisms in NLRP3-Q750K (rs35829419), NLRP3 (rs10733113), CARD8-C10X (rs2043211), NLRP1 (rs8079034), and NLRP1 (rs878329).Results: Significant associations were found with the genotype AA (vs AT+TT) of rs2043211 for PsA patients compared with controls [odds ratio (OR), 95% confidence interval (CI) 1.32 (1.05-1.65), p = 0.016]; and between the C-allele of rs878329 and axial involvement of PsA [OR (95% CI) 1.37 (1.02-1.84), p = 0.035], the T-allele of rs8079034 with prescription of conventional synthetic disease-modifying anti-rheumatic drugs [OR (95% CI) 1.76 (1.23-2.53), p = 0.0020], the G-allele of rs10733113 and patients with a skin disease with early onset [OR (95% CI) 1.58 (1.13-2.21), p = 0.007], and the C-allele of rs35829419 and a destructive/deforming disease [OR (95% CI) 1.63 (1.04-2.55), p = 0.030].Conclusions: This study is the first to show an association with a genetic polymorphism in an inflammasome-related gene, CARD8-C10X (rs2043211), in patients with PsA. Associations between different phenotypes of PsA and different polymorphisms of the inflammasome genes were also found. Our results indicate the involvement of inflammasome genes in the pathogenesis and disease expression of PsA.

Interleukin-6 and soluble interleukin-2 receptor alpha-markers of inflammation in patients with psoriatic arthritis?

OBJECTIVE: To evaluate a possible systemic effect of joint inflammation in contrast to skin disease only, by measuring IL-6 and IL-2sRalpha. METHODS: Two hundred and nineteen patients (111 male / 108 female, age 50.4+/-14.5 yrs (mean+/-SD)) with psoriasis were clinically and laboratory examined. 134 patients had inflammatory joint manifestations defined as peripheral arthritis and/or axial disease, of whom 37 had measurable inflammation, defined as ESR >25 mm/h and/or CRP >15 mg/L. RESULTS: Interleukin-6 was significantly higher in patients with joint disease and measurable inflammation ((median, Q1-Q3) 4.07, 0.92-14.60), and in patients without measured inflammation (1.22, 0.70-3.46), compared to patients with skin disease only (0.70, 0.70-1.73, p<0.001 and p=0.002 respectively). The difference between the two groups of patients with inflammatory joint manifestations was significant (p=0.001). The levels of IL-6 correlated with the actual number of joints affected with arthritis (p<0.001; rs=0.248), ESR (p<0.001; rs=0.459), CRP (p<0.001; rs=0.314) and IL-2sRalpha (p=0.002; rs=0.210). The levels of IL-2sRalpha. did not differ between the 3 groups. CONCLUSION: In this study, IL-6 was significantly higher in patients with psoriasis and inflammatory joint disease with or without routine measurable inflammatory activity compared with patients having psoriasis of the skin. We found that patients with psoriasis and joint inflammation may have systemic effects that could be captured by serum measurements of IL-6. Soluble IL-2Ralpha was not a marker of inflammation in this study.

Psoriatic arthritis-new insights give new options for treatment.

Psoriatic arthritis (PsA), an inflammatory joint disease associated with psoriasis of the skin, has a heterogeneous pattern expressed by different manifestations, such as mild mono-oligoarthritis, a very severe, erosive and destructive polyarthritis indistinguishable from rheumatoid arthritis, and spondylarthropathy with axial involvement or enthesitis. The disease pattern often differs between patients as well as within the same patient over time. Measurable inflammatory activity is not always evident. Early detection of inflamed joints or axial involvement in patients with PsA is important in order to reduce the inflammation and prevent destruction, deformity and functional disability in the joints involved. Several factors, e.g., genetic, immunological, environmental and vascular, have been proposed to be of importance for the aetiology, the expression and prognosis of PsA. The basic treatment for PsA has been administration of non-steroid anti-inflammatory drugs (NSAIDs). Few disease modifying anti-rheumatic drugs (DMARDs) have been available due to a lack of efficacy of most of the DMARDs used for other rheumatic diseases. New insights into genetic, immunological and vascular factors in PsA are of interest as possible targets for future therapy and will be discussed in this review.

Antibodies against cyclic citrullinated peptide (CCP) in psoriatic patients with or without joint inflammation.

OBJECTIVE: To compare the prevalence of anti-CCP antibodies in psoriatic patients with and without joint inflammation, patients with early RA, and controls. METHODS: Anti-CCP antibodies (cut off level 5 U/ml) were measured in 160 patients with psoriatic arthritis (PsA), 146 patients with psoriasis but no arthritic disease, 101 patients with early RA, and 102 healthy controls by ELISA. RESULTS: 11 (7%) patients with PsA, 75 (74%) patients with early RA, 2 (2%) healthy controls (2%), and 1 (0.7%) patient with psoriasis without arthritis had anti-CCP antibodies above the cut off level. The presence of anti-CCP antibodies was not related to radiological changes and/or deformity and functional impairment in PsA. 8/11 patients with PsA and anti-CCP antibodies had a polyarthritic disease, and all fulfilled the ACR criteria for RA at 4 year follow up. Five of these 8 patients also had manifestations such as dactylitis, DIP involvement, radiological changes associated with PsA, and/or enthesitis. In multiple logistic regression analysis with polyarthritis as the dependent variable, anti-CCP antibodies and rheumatoid factor significantly distinguished RA from PsA. CONCLUSIONS: Anti-CCP antibodies were more prevalent in patients with PsA than in patients with psoriasis without arthritis, but less prevalent than in patients with early RA. Patients with PsA positive for anti-CCP antibodies more often had polyarthritic disease, but the presence of anti-CCP antibodies did not relate to radiological changes and/or deformity and functional impairment.

Disease manifestations and HLA antigens in psoriatic arthritis in northern Sweden.

The aim of this study was to identify potential markers of aggressive joint manifestations and HLA associations in patients with psoriatic arthritis (PsA) in northern Sweden. Patients with PsA were examined clinically, with laboratory tests and radiologically. The classification of the disease was based on peripheral and/or axial engagement. HLA B17, B37 and B62 were significantly increased in PsA patients. Univariate analyses suggest that the HLA antigens B37, B62 and some clinical variables were associated with disease course. However, in multivariate analyses distal interphalangeal joint affliction and polyarticular manifestations were the only variables remaining significantly associated with irreversible joint destruction or deformity. There were no significant effects of HLA antigens. In this cross-sectional study, clinical manifestations were more reliable predictors of aggressive joint damage than were specific HLA antigens. However, HLA antigens seemed to modify the expression of the joint disease rather than being involved in joint disease susceptibility.

Renal abnormalities in a population of patients with psoriatic arthritis.

OBJECTIVE: To investigate the prevalence of and to identify predictive factors for renal abnormalities in patients with psoriatic arthritis (PsA). METHODS: 73 patients with PsA were consecutively examined by laboratory analyses and clinically for joint manifestations. Renal function was estimated by creatinine clearance and urinary albumin. RESULTS: 17 (23.3%) of the patients had renal abnormalities as defined by creatinine clearance below the lower cut off of normal distribution (mean - 2 SD) and/or urinary excretion of albumin more than 25 mg/24 h. These patients were significantly older at the time of the study, older at joint disease onset, had longer skin disease duration, increased serum levels of beta2-microglobulin, and higher incidence of increased ESR and/or CRP levels. Increased ESR/CRP levels had significantly predictive value in multivariate analysis. CONCLUSIONS: In this study subclinical renal abnormalities was a prevalent finding. Predictive factor was inflammatory activity measured by laboratory variables. There were no predisposing effects of NSAID or DMARD therapy.