Treatment-related changes in serum neutrophil gelatinase-associated lipocalin (NGAL) in psoriatic arthritis: results from the PIPA cohort study.

OBJECTIVES: Obesity and psoriatic arthritis (PsA) have a complicated relationship. While weight alone does not cause PsA, it is suspected to cause worse symptoms. Neutrophil gelatinase-associated lipocalin (NGAL) is secreted through various cell types. Our objective was to assess the changes and trajectories in serum NGAL and clinical outcomes in patients with PsA during 12 months of anti-inflammatory treatment. METHOD: This exploratory prospective cohort study enrolled PsA patients initiating conventional synthetic or biological disease-modifying anti-rheumatic drugs (csDMARDs/bDMARDs). Clinical, biomarker, and patient-reported outcome measures were retrieved at baseline, and 4 and 12 months. Control groups at baseline were psoriasis (PsO) patients and apparently healthy controls. The serum NGAL concentration was quantified by a high-performance singleplex immunoassay. RESULTS: In total, 117 PsA patients started a csDMARD or bDMARD, and were compared indirectly at baseline with a cross-sectional sample of 20 PsO patients and 20 healthy controls. The trajectory in NGAL related to anti-inflammatory treatment for all included PsA patients showed an overall change of -11% from baseline to 12 months. Trajectories in NGAL for patients with PsA, divided into treatment groups, showed no clear trend in clinically significant decrease or increase following anti-inflammatory treatment. NGAL concentrations in the PsA group at baseline corresponded to the levels in the control groups. No correlation was found between changes in NGAL and changes in PsA outcomes. CONCLUSION: Based on these results, serum NGAL does not add any value as a biomarker in patients with peripheral PsA, either for disease activity or for monitoring.

Increased prevalence of sleep disturbance in psoriatic arthritis is associated with inflammatory and non-inflammatory measures.

OBJECTIVES: To examine the prevalence of sleep disturbances, quantified by the Pittsburgh Sleep Quality Index (PSQI), in patients with psoriatic arthritis (PsA), psoriasis (PsO) and healthy controls (HCs), explore associations between PSQI and clinical and patient-reported outcomes, and evaluate the effect of treatment on PSQI. METHOD: Patients were included from the Parker Institute's PsA patient cohort to evaluate the prevalence of sleep disturbances. Univariate and multivariate regression analyses were used to explore associations between sleep disturbance and outcome measures. Treatment effect in PsA patients was assessed with a mixed-effect model for repeated measures. RESULTS: In total, 109 PsA patients, 20 PsO patients, and 20 HCs were included. Sleep disturbances were reported by 66.1% of PsA patients, 45.0% of PsO patients, and 15.0% of HCs. Univariate regression analyses revealed statistically significant associations (p < 0.001) between PSQI and Disease Activity Score (DAS28CRP), tender points, visual analogue scale (VAS) patient global and pain, Psoriatic Arthritis Impact of Disease fatigue, Health Assessment Questionnaire (HAQ), and painDETECT score. Multivariate regression analysis demonstrated VAS patient global, VAS pain, and tender points as being independently associated with PSQI. The mixed-effect model revealed no effect of treatment. CONCLUSION: More PsA patients than PsO patients and HCs reported sleep disturbances. Sleep disturbances were associated with inflammatory and non-inflammatory measures possibly explaining the limited effect of treatment. This demonstrates the need for interdisciplinary approaches to improve the management of sleep disturbance in PsA.Trial registration: ClinicalTrials.gov (NCT02572700).