Children with psoriasis are significantly more likely to develop obesity, hyperlipidemia, hypertension, diabetes, metabolic syndrome, polycystic ovarian syndrome, liver disease, and elevated liver enzymes than are children without the disease, according to a retrospective review of insurance claims data.
These risks are independent of obesity status: in non-obese children with psoriasis, the risk of comorbidities was 40% to 75% higher than in children without psoriasis, reported Megha M. Tollefson, MD, of the Mayo Clinic in Rochester, MN, and colleagues. But even in children without psoriasis, obesity was a much stronger contributor to comorbidities.
“In recent years, it has become increasingly clear that psoriasis is more than a ‘skin-deep’ condition and that it may frequently be associated with other systemic comorbidities, even in children,” the researchers wrote online in JAMA Dermatology. “While the association in adult patients is well established, the patterns and predictors of the risk of comorbidities in children with psoriasis are still not clear.
“There is mounting evidence that children with psoriasis are more likely to be obese than children without psoriasis, but this finding begs the question of whether the systemic comorbidities that are seen in children with psoriasis are attributable to obesity, or whether psoriasis is actually an independent risk factor for these comorbidities.”
In this study of claims from Optum Laboratories Data Warehouse, a Massachusetts-based Mayo Clinic partner, the researchers studied de-identified records of 29,957 children with psoriasis (affected children) and 29,957 children without psoriasis, matched for age, sex, and race, from 2004 through 2013.
The children, all under age 19, were divided into four groups:
- Non-obese without psoriasis (reference cohort)
- Non-obese with psoriasis
- Obese without psoriasis
- Obese with psoriasis
The average age of the children was 12.0, and 53.5% of the total were girls. At baseline, more affected children were obese than non-obese (2.9% versus 1.5%; P<0.001).
The average follow-up period for both groups was about 3 years. During this time, pediatric psoriasis patients were significantly more likely to develop comorbidities than those without psoriasis, with non-alcoholic liver disease, diabetes, and hypertension showing the highest risks.
Among non-obese children, the risk of comorbidities was significantly higher in those with psoriasis; these included elevated lipid levels (HR 1.42), hypertension (HR 1.64), diabetes (HR 1.58), metabolic syndrome (HR 1.62), polycystic ovarian syndrome (HR 1.49), non-alcoholic liver disease (HR 1.76), and elevated liver enzyme levels (HR 1.46).
Even in children without psoriasis, obesity was a much stronger contributor to comorbidities, carrying an 18-fold higher risk of non-alcoholic liver disease, a 16-fold higher risk of metabolic syndrome, a seven-fold higher risk of hypertension, a six-fold higher risk of hyperlipidemia, an almost three-fold higher risk of diabetes, and a 2.3-fold higher risk of elevated liver enzyme levels than the reference group; there was also a six-fold higher risk of polycystic ovarian syndrome in girls.
When the researchers analyzed the interaction between obesity and psoriasis, they found none, suggesting that while both obesity and psoriasis contribute to the development of pediatric comorbidities, the effect is additive, not exponential.
Asked for her perspective, Amy Paller, MD, chair of the Department of Dermatology at Northwestern Medicine Feinberg School of Medicine in Chicago, who was not involved with the study, noted that several studies have clearly demonstrated the association of obesity and pediatric psoriasis, and a large recent study also linked a high waist circumference to height ratio to more severe pediatric psoriasis. “The association of a variety of other ‘metabolic syndrome’ comorbidities has been controversial, however, and whether it is the obesity or psoriasis itself that increases the risk remains unknown.
“While there are issues with the use of a claims database, especially given the frequent misdiagnosis of psoriasis by non-dermatologists, several metabolic-related disorders were shown to be significantly increased in risk,” she said, adding that the fact that the associations were seen even among non-obese psoriasis patients suggests that early systemic intervention might lower risks.
The study has several limitations, Tollefson and colleagues noted. For example, it relies on data from administrative claims, and the diagnoses were not confirmed by medical record review. Also of possible concern are undercoding and misclassification of comorbidities. Extremely obese children would be more likely to have a corresponding obesity code than those with a body mass index of 25 to 40, the researchers added. “The lower prevalence of obesity in our cohort than in some others suggests that obesity may have been undercoded as a whole, with the resulting contribution from psoriasis being slightly overestimated.”
In addition, systemic medications used to treat psoriasis potentially might have influenced the risk of some comorbidities.