Normal C-reactive protein in active psoriatic arthritis: results from real-world clinical practice

An interpretable machine learning approach for detecting psoriatic arthritis in a UK primary care psoriasis cohort using electronic health records from the Clinical Practice Research Datalink

OBJECTIVES

Develop an interpretable machine learning model to detect patients with newly diagnosed psoriatic arthritis (PsA) in a cohort of psoriasis patients and identify important clinical indicators of PsA in primary care.

METHODS

We developed models using UK primary care electronic health records from the Clinical Practice Research Datalink (CPRD). The study population consisted of a cohort of (PsA free) patients with incident psoriasis who were followed prospectively. We used Bayesian networks (BNs) to identify patients who developed PsA using primary care variables measured prior to diagnosis and compared the results to a random forest (RF). Variables included patient demographics, musculoskeletal symptoms, blood tests, and prescriptions. The importance of each variable used in the models was evaluated using permutation variable importance. Model discrimination was measured using the area under the receiver operating characteristic curve (AUC) and the area under the precision-recall curve (PRAUC).

RESULTS

We identified a cohort of 122,330 patients with an incident psoriasis diagnosis between 1998 and 2019 in the CPRD, of whom 2460 patients went on to develop PsA. Our best BN achieved an AUC of 0.823, and PRAUC of 0.221, compared to the AUC of 0.851 and PRAUC of 0.261 of the RF. Psoriasis duration, nonsteroidal anti-inflammatory drug prescriptions, nonspecific arthritis, nonspecific arthralgia, and C-reactive protein blood tests were all important variables in our models.

CONCLUSIONS

We were able to identify psoriasis patients at higher risk, and important indicators, of PsA in UK primary care. Further work is required to evaluate our model's usefulness in assisting PsA screening.

Prevalence of psoriatic arthritis in Italy: insights from the multicentric MAPSI study

Introduction

Psoriatic arthritis (PsA) is a chronic inflammatory arthropathy associated with cutaneous psoriasis (PsO), first defined by Moll and Wright. Initially perceived as relatively benign, PsA is now recognized for its chronic, progressive, and destructive nature, significantly impacting patients' quality of life, similar to Rheumatoid Arthritis (RA). Globally, PsA represents about 20% of cases in early arthritis clinics, posing diagnostic and management challenges. Early diagnosis is crucial to prevent long-term disability and prevent comorbidities. While classification criteria for PsA are widely accepted, the lack of specific diagnostic criteria may delay diagnosis, with many patients experiencing delays of over a year before receiving an accurate diagnosis. For this reason, the exact prevalence of PsA remains uncertain.

Methods

The MAnagement of PSoriatic Arthritis in Italy (MAPSI) project is a multicenter observational study aimed to investigate the prevalence of PsA and characteristics in an Italian cohort. This study included 454 patients diagnosed or confirmed by a rheumatologist across 25 Rheumatology Units in Italy. Data were collected on demographics, clinical features, and treatment histories. In our cohort, distinct gender differences were observed in PsA phenotype and disease impact.

Results

Men had a higher prevalence of axial involvement and were more likely to be current or former smokers, while women showed greater rates of enthesitis and reported higher perceived disease activity. Additionally, women had a higher prevalence of psychological comorbidities, whereas men had more severe skin involvement; laboratory tests were often unhelpful in diagnosing PsA, with elevated inflammatory markers in only about half of the cases.

Discussion

These findings highlight the need for gender-sensitive approaches in the management of PsA. Our findings highlight the importance of comprehensive patient evaluation, including extramuscoloskeletal manifestation with a gender-sensitive approaches, focusing on a prompt diagnosis to prevent systemic comorbidities. Real-world data, such as those provided by the MAPSI study, are essential for understanding the burden of PsA and developing effective management strategies tailored to patient characteristics.

Utility of multi-biomarker panel on discriminating disease activity in patients with psoriatic arthritis

OBJECTIVE

To investigate the correlation of serum protein biomarkers and disease activity in patients with PsA.

METHODS

176 patients fulfilled the CASPAR (ClASsification criteria for Psoriatic ARthritis) were recruited in this cross-sectional study. The level of 48 protein biomarkers, cartilage and bone turn-over markers were assessed. The patients were randomly divided into a derivation-cohort and a validation-cohort at a ratio of 7:3. Patients were further categorized based on their disease activity states using cDAPSA (remission/low disease activity and moderate/high disease activity). Least absolute shrinkage and selection operator (LASSO) was used to select biomarkers which were associated with moderate/high disease activity in the derivation cohort. Receiver operating characteristic (ROC) curve, GiViTI calibration belt were used to assess the performance of the model in both cohorts.

RESULTS

The cohort [age: 55.5 (44.0-62.75) years, male: 80 (45.5 %)] had moderate disease activity [DAPSA: 15.9 (8.3-26.9); PASI: 3.2 (0.5-6.8)]. 101 PsA patients (57.4 %) had clinical DAPSA moderate/high disease activity. Biomarker levels associated with moderate/high disease activity included SAA (Serum amyloid A), IL-8 (Interleukin 8), IP10 (Interferon gamma-induced protein 10)/CXCL10, M-CSF (Macrophage colony-stimulating factor), SCGF-β (Stem cell growth factor), SDF-1α (Stromal cell-derived factor 1α)/CXCL12. The model's equation including the 6 biomarker levels was applied to the validation-cohort. The area under the ROC curve (AUC) for discriminating moderate/high disease activity was 0.802 and 0.835 for the derivation-and-validation-cohorts, respectively. The multi-biomarkers panel model had higher-AUC when compared with that of C-reactive protein (CRP) (AUC = 0.727, p = 0.022). The P-values of calibration charts in the two sets were 0.902 and 0.123.

CONCLUSIONS

The multi-biomarkers panel demonstrated the ability to discriminate patients with moderate/high disease activity from those with low disease activity/remission.

Comparative profiling of serum biomarkers and ATR-FTIR spectroscopy for differential diagnosis of patients with rheumatoid and psoriatic arthritis - a pilot study

BACKGROUND

Rheumatoid arthritis (RA) and psoriatic arthritis (PsA) are chronic inflammatory diseases in which innate and adaptive responses of the immune system are induced. RA and PsA have complex signaling pathways. Despite the differences in their clinical presentation, there is a great demand for fast and accurate diagnosis of diseases to implement treatment and plan an individual therapeutic strategy quickly. In this report, we present the results of differential diagnosis of patients with RA and PsA and healthy subjects (C, control group), allowing for reliable differentiation of groups of rheumatoid patients based on biochemical parameters, attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectra, and combined data sets.

MATERIALS AND METHODS

Biochemical analyses, ELISA (enzyme-linked immunosorbent assays), and multiplex assays were conducted for blood sera from patients with RA (n = 32), patients with PsA (n = 28), and the control group (n = 18). ATR-FTIR spectra were collected for lyophilized sera.

RESULTS

The combination of six biochemical parameters (WBC, ESR, RF, CRP, HCC-4/CCL16, and HMGB1/HMGB) allowed the development of the partial least squares discriminant analysis (PLS-DA) model with an overall accuracy (OA) of 80% for test samples. The best separation between RA, PsA, and the control group was obtained utilizing spectral data. Using the interval PLS algorithm (iPLS) specific spectral ranges were selected and a classifier characterized by OA value for test set equal to 88% was obtained. This parameter, for the hybrid PLS-DA model constructed using selected biochemical parameters and a significantly reduced number of spectral variables, reached the level of 84%.

CONCLUSIONS

PLS-DA models developed on the basis of spectral data enable effective differentiation of patients with RA, patients with PsA, and healthy subjects. They appeared to be insensitive to existing inflammation processes which opens interesting perspectives for new diagnostic tests and algorithms for identification of patients with RA and PsA.

Synergistic effect of periodontitis and C-reactive protein levels on mortality: NHANES 2001-2004

Periodontitis is associated with elevated C-reactive protein (CRP) levels. Although the coexistence of periodontitis and elevated CRP levels may heighten the risk of mortality, previous studies have not confirmed their synergistic effect. Understanding this interaction is crucial for identifying potential interventions to reduce mortality risk in individuals with periodontitis. This study aimed to assess the synergistic effects of periodontitis and elevated CRP levels on mortality in 7,938 adult individuals who participated in the National Health and Nutrition Examination Study 2001-2004. The association of periodontitis status and CRP levels with mortality was assessed using a survey-weighted Cox model. The interactive effect was estimated; the synergistic effect of CRP levels and periodontitis status on mortality was assessed using the relative excess risk due to interaction (RERI). Periodontitis was diagnosed in 1,065 (13.4%) participants. Compared with the participants without periodontitis and possessing CRP levels of ≤ 0.5 mg/dL, those with periodontitis (hazard ratio [HR], 1.38) or CRP levels of > 0.5 mg/dL (HR 1.23) had higher HRs. The participants with both periodontitis and CRP levels of > 0.5 mg/dL had the highest HR of 2.01. The additive scale interactive effect of the periodontal status and CRP levels, measured using RERI 0.41 (-0.07, 0.95), was positive and nearly significant in the total population. The synergy between the periodontal status and CRP levels was more prominent in the participants aged ≥60 years than that in younger individuals. Periodontitis with high CRP levels may indicate a high mortality rate, indicating the importance of active monitoring and intensive management of periodontitis and inflammatory markers.

Study of the Gut Microbiome in Patients with Psoriatic Arthritis

Background

Gut dysbiosis may play a role in immune-mediated diseases, such as psoriasis. There is a growing interest in understanding microbiome influence, with speculations around the importance of an altered gut microbiome linked to the progression to psoriatic arthritis in psoriasis. The objective of this study is to study the gut microbiome in patients with severe psoriatic disease with or without psoriatic arthritis.

Methods

V3/V4 16S rRNA gene sequencing and bioinformatics analyses were performed with the total DNA extracted from the stool samples of 30 patients with psoriatic disease, 15 of whom had documented psoriatic arthritis.

Results

We found differences in gut microbiome composition in psoriatic arthritis patients when looking for relative and especially differential abundances. Bacteroidaceae family (P = .02), Bacteroides genus (P=.02), and Bacteroides uniformis (P=.03) were more abundant in psoriatic arthritis patients on differential abundance, adjusted for each taxonomic level. However, the present study did not show significant differences in alpha or beta diversity.

Conclusion

This study shows different patterns of gut microbiome composition in patients with psoriatic arthritis, with significant overexpression of the Bacteroides genus. This reinforces the microbiome as a field of interest in psoriasis. Nevertheless, it should be noted that some previously described findings related to lower diversity and different clustering between groups could not be demonstrated, probably due to the small number of patients. Additionally, it remains difficult to understand the magnitude of the gut microbiome influence. Is dysbiosis a cause or consequence of the disease? However, the microbiome deserves our attention, especially since it brings different opportunities for intervention through diet, prebiotics and probiotics, pretreatment analysis, prognosis, and even microbiome modulation and transplantation.

Sex-specific differences in patients with psoriatic arthritis:a nationwide study from the Chinese Registry of Psoriatic Arthritis (CREPAR IV)

OBJECTIVES

To elucidate the sex-specific differences in demographic features, clinical characteristics, and quality of life in Chinese patients with psoriatic arthritis (PsA).

METHODS

A total of 1,074 patients with PsA registered between December 2018 and June 2021 from the Chinese REgistry of Psoriatic ARthritis (CREPAR) cohort were selected. The baseline data on demographics, clinical characteristics, commonly used laboratory tests, comorbidities, and quality of life assessments were collected for this cross-sectional analysis.

RESULTS

A total of 1,074 patients were included in this study, 585 (54.47%) of them were male and 489 (45.53%) were female. The age at PsA onset in male patients was earlier than that in female patients (38.10 ± 12.79 vs 40.37 ± 13.41, p = 0.005). For clinical characteristics, male patients presented with higher rates of axial involvement (43.89% vs 37.74%, p = 0.044) and nail involvement (66.15% vs 58.08%, p = 0.006), while female patients presented with higher rates of peripheral arthritis (89.57% vs 83.93%, p = 0.007). For laboratory tests, men presented with a higher percentage of HLA-B27 positivity than women (24.65% vs 16.70%, p = 0.002) and had higher levels of CRP (median 9.70 vs 5.65, p < 0.001). Regarding disease assessment indices, male patients scored higher in PASI and BASFI (median 5.00 vs 3.00, p = 0.007 and 1.80 vs 1.40, p = 0.012, respectively). No sex difference was found in rates of achieving remission. Factors associated with disease remission were also analyzed in both sexes.

CONCLUSION

Demographic and clinical characteristics tend to vary between male and female patients with PsA. Male patients reported more functional limitations in daily life. Key Points • The demographic and clinical features vary greatly between male and female patients with PsA. • Male patients reported more functional burden in daily life as measured by BASFI.

Earlier clinical response predicts low rates of radiographic progression in biologic-naïve patients with active psoriatic arthritis receiving guselkumab treatment

OBJECTIVE

Assess relationship between earlier clinical improvement and radiographic progression (RP) over 2 years in guselkumab-treated patients with active psoriatic arthritis (PsA).

METHOD

Post hoc analyses combined data from DISCOVER-2 biologic-naïve adults with active PsA randomized to either guselkumab 100 mg every 4 weeks (Q4W) or guselkumab at W0, W4, then Q8W. Correlations (Spearman's coefficient) between baseline disease parameters and total PsA-modified van der Heijde-Sharp (vdH-S) score were examined. Repeated-measures mixed models, adjusted for known RP risk factors, assessed the relationship between Disease Activity Index in PsA (DAPSA) improvement, DAPSA improvement exceeding the median or the minimal clinically important difference (MCID), or DAPSA low disease activity (LDA) at W8 and RP rate, assessed by change from baseline in vdH-S score through W100.

RESULTS

Baseline age, PsA duration, CRP level, and swollen joint count, but not psoriasis duration/severity, weakly correlated with baseline vdH-S score. Elevated baseline CRP (parameter estimate [β] = 0.17-0.18, p < 0.03) and vdH-S score (β = 0.02, p < 0.0001) significantly associated with greater RP through W100. Greater improvement in DAPSA (β = -0.03, p = 0.0096), achievement of DAPSA improvement > median (least squares mean [LSM] difference: -0.66, p = 0.0405) or > MCID (-0.67, p = 0.0610), or DAPSA LDA (-1.44, p = 0.0151) by W8 with guselkumab significantly associated with less RP through W100. The effect of W8 DAPSA LDA on future RP was strengthened over time among achievers vs. non-achievers (LSM difference enhanced from -1.05 [p = 0.0267] at W52 to -1.84 [p = 0.0154] at W100).

CONCLUSIONS

In guselkumab-treated patients with active PsA, earlier improvement in joint symptoms significantly associated with lower RP rates through 2 years, indicating blockade of the IL-23 pathway may modify long-term disease course and prevent further joint damage. Key Points • Greater improvement in DAPSA at Week 8 of guselkumab treatment was significantly associated with less progression of structural joint damage at 2 years in patients with active psoriatic arthritis (PsA). • Early control of peripheral joint disease activity with blockade of the IL-23 pathway may modify long-term PsA trajectory and prevent further joint damage.

Type-I interferon pathway and DNA damage accumulation in peripheral blood of patients with psoriatic arthritis

Objectives

The abnormal DNA damage response is associated with upregulation of the type-1 interferon (IFN-I) pathway in certain rheumatic diseases. We investigated whether such aberrant mechanisms operate in psoriatic arthritis (PsA).

Methods

DNA damage levels were measured by alkaline comet assay in peripheral blood mononuclear cells from 52 PsA patients and age-sex-matched healthy individuals. RNA expression of IFIT1, MX1 and IFI44, which are selectively induced by IFN-I, was quantitated by real-time polymerase chain reaction and their composite normalized expression resulted in IFN-I score calculation. RNA expression of IL1β, IL6, TNF, IL17A and IL23A was also assessed in PsA and control subgroups.

Results

In PsA, DNA damage accumulation was increased by almost two-fold compared to healthy individuals (olive tail moment arbitrary units, mean ± SD; 9.42 ± 2.71 vs 4.88 ± 1.98, p<0.0001). DNA damage levels significantly correlated with serum C-Reactive-protein and IL6 RNA expression in PBMCs. Despite increased DNA damage, the IFN-I score was strikingly lower in PsA patients compared to controls (-0.49 ± 6.99 vs 4.24 ± 4.26; p<0.0001). No correlation was found between IFN-I pathway downregulation and DNA damage. However, the IFN-I score in a PsA subgroup was lower in those patients with higher IL1β expression, as well as in those with higher TNF/IL23A PBMCs expression.

Conclusion

DNA damage in PsA correlates with measures of inflammation but is not associated with the IFN-I pathway induction. The unexpected IFN-I downregulation, albeit reminiscent to findings in experimental models of spondyloarthritis, may be implicated in PsA pathogenesis and explained by operation of other cytokines.

Serum Calprotectin as a Promising Inflammatory Biomarker in Psoriatic Arthritis: a 1-Year Longitudinal Study

INTRODUCTION

There are few biomarkers correlated with psoriatic arthritis (PsA). We aimed to explore the clinical value of calprotectin (CLP) in PsA in disease activity and treatment targets.

METHODS

Serum CLP was detected by enzyme-linked immunosorbent assay (ELISA) in 71 patients with PsA, 55 patients with psoriasis (PsO), and 10 healthy controls. The association of serum CLP with disease activity index at baseline and follow-up was analyzed. Cox regression and receiver operating characteristic (ROC) analysis were used to evaluate the potential of CLP for predicting the achievement of treatment targets, including low disease activity (LDA), remission, and minimal disease activity (MDA).

RESULTS

Serum CLP levels (μg/ml) were significantly increased in patients with PsA/PsO compared with healthy controls (p < 0.001). Serum CLP levels were positively associated with psoriasis area and severity index (PASI), disease activity in psoriatic arthritis (DAPSA), and its components [including tender joint count (TJC), swollen joint count (SJC), patient's global assessment (PGA), and visual analog scale (VAS)-pain, r 0.290-0.601, all p value < 0.05]. After 1-year follow-up, the number of patients with PsA in remission and MDA increased [17 (23.9%) versus 47 (66.1%) and 21 (29.5%) versus 52 (73.2%) respectively, all p value < 0.001]. Cox regression and Kaplan-Meier survival analysis indicated that patients with lower CLP obtain LDA, MDA, and remission earlier, including remission and MDA within a year (all p-value < 0.05). ROC analysis showed the ability of serum at baseline to predict the achievement of the treatment target in 3 months [area under the curve (AUC) 0.663-0.691, all p-values < 0.05].

CONCLUSIONS

Serum CLP level was correlated with disease activity in PsA. It also possessed the ability to predict the achievement of the therapeutic target. These features of CLP would make it a useful tool in clinical work.