Background/Purpose:   Studies in adults have shown a significant association between obesity and psoriatic arthritis. The association of obesity with pediatric psoriatic arthritis is unknown. We aimed to evaluate the prevalence of obesity in a pediatric psoriatic arthritis cohort.

Methods: We conducted a retrospective cross-sectional study of children with psoriatic arthritis evaluated at a single center between 6/2010 and 9/2014.  The cohort consisted of children with an ICD-9-CM code of 696.0 “Psoriatic arthritis” given at diagnosis or a subsequent follow-up visit. Age- and sex-specific Z-scores for weight, height, and body mass index (BMI) were calculated based on the 2000 CDC Growth data.  Overweight or obese was defined as a BMI greater than or equal to the 85^th and 95^thpercentile, respectively. Differences in clinical and demographic characteristics who were overweight and not overweight were assessed using Wilcoxon rank sum test, t-test or chi-squared test, as appropriate. The association of age, sex, active joint count, and presence of psoriasis with being overweight was tested using univariate logistic regression. The reference population consisted of 909 healthy participants recruited from general pediatric clinics in the surrounding community for multiple studies done by the Nutrition and Growth laboratory at our institution.

Results: During the study period 48 children with psoriatic arthritis were evaluated. 34 (71%) were female and 17 (35.4%) had a first-degree relative with psoriasis.  29 (60.4%) and 19 (39.6%) of children had psoriasis or dactylitis at diagnosis, respectively. 3 (6.3%) and 5 (10.4%) of the children with psoriatic arthritis were overweight or obese, respectively. Mean BMI z-scores for children with psoriatic arthritis and the reference group were 0.40 (SD 0.96) and 0.36 (SD 1.01), respectively. In comparison to the reference population the proportion of children with psoriatic arthritis who were overweight was not statistically different (0.30 versus 0.17; p=0.06). Comparison of demographics and clinical features between those children with psoriatic arthritis who were overweight and not overweight are shown in the Table. In univariate logistic regression, female sex was associated with significantly decreased odds of being overweight (Odds ratio: 0.17, 95% CI: 0.03 to 0.87). Age, disease duration, psoriasis, dactylitis, and active joint count at diagnosis were not significantly associated with being overweight.

Conclusion: 17% of our psoriatic arthritis cohort was overweight or obese. Female sex was associated with decreased odds of being overweight. The lack of association of obesity with pediatric psoriatic arthritis may be secondary to our limited sample size or may be reflective of true differences in pediatric and adult disease.

Table. Comparison of demographic and clinical features of children who were not overweight and those who were overweight or obese

Legend ^active joint count at diagnosis

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/obesity-and-pediatric-psoriatic-arthritis/