Background: Relatively little is known about the epidemiology of juvenile psoriatic arthritis (PsA), including clinical features associated with the development of arthritis among children with psoriasis and subsequent risk of inflammatory comorbidities. Objective: To identify the overall risk of arthritis among children with psoriasis and subsequent risk of inflammatory comorbidities. Methods: Using Clinformatics™ DataMart (OptumInsight, Eden Prairie, MN) de-identified US administrative claims data from 2000–2013, we identified children 0–16 years with an incident diagnosis of psoriasis or PsA using ICD-9-CM diagnostic, procedure and pharmacy billing codes. Cox proportional hazard regression was performed to assess clinical features associated with development of arthritis in children with psoriasis. Incidence rate ratios were used to compare the relative frequency of co-morbid diagnoses. Results: We identified 212 children with PsA, 4,312 with psoriasis-only, and 45,240 controls. Approximately 33% of children with PsA received a diagnostic code for psoriasis before arthritis. Median time to index code for arthritis after index code for psoriasis was 17.6 months (IQR 4.1–38.1). Older age and uveitis were associated with a significantly increased risk of developing arthritis in children with psoriasis. Children with PsA had a significantly increased risk of uveitis, diabetes, and depressive disorder when compared to patients with psoriasis and inflammatory bowel disease, uveitis, diabetes, and depressive disorder when compared to controls. Conclusion: Most children with PsA developed arthritis first. Older age and uveitis were risk factors for arthritis among children with psoriasis. PsA was associated with increased risk of several clinically relevant inflammatory comorbidities.

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Objective The goal was to characterize short‐term kidney status and describe variation in early care utilization in a multicenter cohort of patients with childhood‐onset systemic lupus erythematosus (cSLE) and nephritis. Methods We analyzed previously collected prospective data from North American patients with cSLE with kidney biopsy‐proven nephritis enrolled in the Childhood Arthritis and Rheumatology Research Alliance (CARRA) Registry from March 2017 through December 2019. We determined the proportion of patients with abnormal kidney status at the most recent registry visit and applied generalized linear mixed models to identify associated factors. We also calculated frequency of medication use, both during induction and ever recorded. Results We identified 222 patients with kidney biopsy–proven nephritis, with 64% class III/IV nephritis on initial biopsy. At the most recent registry visit at median (interquartile range) of 17 (8–29) months from initial kidney biopsy, 58 of 106 patients (55%) with available data had abnormal kidney status. This finding was associated with male sex (odds ratio [OR] 3.88, 95% confidence interval [95% CI] 1.21–12.46) and age at cSLE diagnosis (OR 1.23, 95% CI 1.01–1.49). Patients with class IV nephritis were more likely than class III to receive cyclophosphamide and rituximab during induction. There was substantial variation in mycophenolate, cyclophosphamide, and rituximab ever use patterns across rheumatology centers. Conclusion In this cohort with predominately class III/IV nephritis, male sex and older age at cSLE diagnosis were associated with abnormal short‐term kidney status. We also observed substantial variation in contemporary medication use for pediatric lupus nephritis between pediatric rheumatology centers. Additional studies are needed to better understand the impact of this variation on long‐term kidney outcomes.

Objective Studies in adults have shown a significant association between obesity and psoriatic arthritis, however the association of obesity with pediatric psoriatic arthritis is unknown. We aimed to evaluate obesity in pediatric psoriatic arthritis. Methods We conducted a cross-sectional study of children with psoriasis and psoriatic arthritis evaluated at a single center between 6/2010 and 9/2014. Two healthy reference populations were utilized: 1) local reference population from the surrounding community and 2) a national reference population derived from NHANES. Age and sex-specific z-scores for weight, height, and body mass index (BMI) were calculated. Differences in clinical and demographic characteristics between groups were assessed. Results During the study period, 48 children with psoriatic arthritis and 231 patients with psoriasis were evaluated. Three (6.2%) and 5 (10.4%) of the children with psoriatic arthritis were overweight or obese, respectively. In comparison to the reference healthy groups and psoriasis patients, the mean BMI z-score of children with psoriatic arthritis was not statistically different. However, patients with psoriasis were more likely to be obese than the community reference population (p-value <0.001). Conclusions Children with psoriasis were more obese than the healthy reference population, however there was no statistically significant difference in obesity between children with psoriatic arthritis and psoriasis or psoriatic arthritis and the reference population. This lack of association may be reflective of true differences in pediatric and adult-onset disease and warrants further investigation.