Association of psoriasis with comorbidity development in children with psoriasis

IMPORTANCE Children with psoriasis are at increased risk for comorbidities. Many children with psoriasis are also overweight or obese; it is unknown whether the increased risk of comorbidities in these children is independent of obesity. OBJECTIVE To determine the risk of elevated lipid levels (hyperlipidemia/hypertriglyceridemia), hypertension, metabolic syndrome, polycystic ovarian syndrome, diabetes, nonalcoholic liver disease, and elevated liver enzyme levels in children with and without psoriasis, after accounting for obesity. DESIGN, SETTING, AND PARTICIPANTS Thiswas a retrospective cohort study of claims data from Optum Laboratories DataWarehouse (includes 150 million privately insured and Medicare enrollees). A cohort of 29 957 children with psoriasis (affected children) and an age-, sex-, and race-matched comparator cohort of 29 957 children without psoriasis were identified and divided into 4 groups: (1) nonobese, without psoriasis (reference cohort); (2) nonobese, with psoriasis; (3) obese, without psoriasis; and (4) obese, with psoriasis. MAIN OUTCOMES AND MEASURES Risk of developing comorbidities (Cox proportional hazards regression). RESULTS The overall mean (SD) age of those included in the cohort was 12.0 (4.4) years, and 16 034 (53.5%) were girls. At baseline, more affected children were obese (862 [2.9%] vs 463 [1.5%]; P < .001 for all comparisons). Children with psoriasis were significantly more likely to develop each of the comorbidities than those without psoriasis (P < .01). Obesity was a strong risk factor for development of each comorbidity, even in those without psoriasis (hazard ratios [HRs] ranging from 2.26 to 18.11). The risk of comorbidities was 40% to 75% higher among nonobese children with vs without psoriasis: elevated lipid levels (HR, 1.42; 95%CI, 1.25-1.62), hypertension (HR, 1.64; 95%CI, 1.40-1.93), diabetes (HR, 1.58; 95%CI, 1.27-1.95), metabolic syndrome (HR, 1.62; 95%CI, 1.13-2.33), polycystic ovarian syndrome (HR, 1.49; 95%CI, 1.18-1.88), nonalcoholic liver disease (HR, 1.76; 95%CI, 1.16-2.65), and elevated liver enzyme levels (HR, 1.46; 95%CI, 1.27-1.67). Except for hypertension (P = .03), no significant interaction occurred between psoriasis and obesity on the risk of comorbidities. CONCLUSIONS AND RELEVANCE Children with psoriasis are at greater risk of developing obesity, hyperlipidemia, hypertension, diabetes, metabolic syndrome, polycystic ovarian syndrome, nonalcoholic liver disease, and elevated liver function enzyme levels than children without psoriasis. While psoriasis is a small independent risk factor for the development of these comorbidities, obesity is a much stronger contributor to comorbidity development in children with psoriasis.