Comorbidities more prevalent in pediatric psoriasis patients

Pediatric psoriasis patients may experience comorbidities, including psychiatric comorbidities, at a greater rate than children without the disease, according to a study published in May 2019 in Pediatric Dermatology.¹ But the incidence of comorbidities doesn’t seem to be impacted by disease severity, says study authors.

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Psoriasis impacts the lives of approximately 0.1% of children in the United States,² and, according to recent studies, the incidence of psoriasis rises linearly with age reaching 1.3% after puberty.^2-4 It is well known that psoriasis carries with it the risk of developing other serious health conditions, but little is known about the prevalence of comorbidities in pediatric psoriasis patients.

Investigators at the Department of Dermatology, Northwestern University Feinberg School of Medicine, Chicago, Ill., looked to fill this gap by completing a retrospective cohort study to evaluate the incidence of comorbidities in pediatric patients with psoriasis.

Researchers gathered retrospective data from the MarketScan Commercial Claims and Encounters Database between January 1, 2009, and June 30, 2015. The database includes inpatient, outpatient and outpatient prescription drug information from 190,000,000 unique patients between 1996 and 2017. The information includes detailed cost, use and outcomes data for healthcare services performed in both inpatient and outpatient settings.

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Investigators used this database to classify patients aged 4 to 17 years into a psoriasis cohort and a non-psoriasis cohort using administrative claims to confirm diagnosis of psoriasis. Of the 38,430 patients that were included in the study, 7,686 had psoriasis and 30,744 did not. For the comparison, study authors paired three relatively healthy patients without psoriasis with every psoriasis patient. They found that, in the psoriasis cohort, the prevalence per 1000 patients of any comorbidity was 49.05; while the prevalence per 1000 patients of any comorbidity in the non-psoriasis cohort was 11.94.

The authors found that individuals in the psoriasis cohort most commonly experienced Crohn’s disease and psoriatic arthritis; while patients in the non-psoriasis cohort experienced diabetes and serious infections. Individuals in the psoriasis cohort also experienced psychiatric comorbidities at a greater rate than the non-psoriasis cohort (22.64 to 13.4, respectively). Of the psychiatric conditions, individuals with psoriasis were most likely to experience depression (16.91), followed by bipolar disorder (4.94) and anxiety (4.55).

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The investigators further examined the psoriasis cohort based on disease severity. Of the patients with psoriasis, 15% were considered moderate-to-severe based on their therapies, which included phototherapy, disease modifying antirheumatic drugs (DMARDs), TNF inhibitors and other biologic therapies. Surprisingly, researchers discovered that patients with moderate-to-severe disease didn’t have a greater incidence of serious infections than patients with mild psoriasis. Furthermore, there was no significant difference between the two subsets regarding the prevalence of other comorbid conditions, such as obesity and psychiatric comorbid conditions, with the exception of anxiety.

The findings of this study reinforce earlier data that indicate an increased prevalence of comorbidities in pediatric patients with psoriasis. But, unlike in previous studies, researchers didn’t find an association between hypertension and diabetes in pediatric patients with psoriasis – although this may be due to the use of claims-based data on ICD-9 coding rather than laboratory data, which was unavailable.

The main strengths of this study were its population size and the method used to compare cohorts. Its retrospective design and dependence on ICD-9 coding rather than laboratory values, however, may have acted as a major limitation to the study. Disease severity was also defined by the treatment modality used to treat patients with the assumption that more treatment means worse disease. This may not have accurately reflected the disease severity of the cohort as patients receiving more therapy could have improved control of their psoriasis, which would reduce their associated comorbid conditions. 

RELATED: The psoriasis – Type 2 diabetes connection

Despite these limitations, the study’s take home message is an important one: physicians should be vigilant in screening all pediatric psoriasis patients for common comorbidities, including psychiatric disorders, as these patients may be more likely to experience serious, life-altering health conditions than children without the disease.

References:

Reference:
1. Paller AS, Schenfeld J, Accortt NA, Kricorian G. A retrospective cohort study to evaluate the development of comorbidities, including psychiatric comorbidities, among a pediatric psoriasis population. Pediatr Dermatol. 2019;36(3):290–297.

2. Burden-teh E, Thomas KS, Ratib S, Grindlay D, Adaji E, Murphy R. The epidemiology of childhood psoriasis: a scoping review. Br J Dermatol. 2016;174(6):1242-57.

3. Gelfand JM, Weinstein R, Porter SB, Neimann AL, Berlin JA, Margolis DJ. Prevalence and treatment of psoriasis in the United Kingdom: a population-based study. Arch Dermatol. 2005;141(12):1537-41.

4. Olsen AO, Grjibovski A, Magnus P, Tambs K, Harris JR. Psoriasis in Norway as observed in a population-based Norwegian twin panel. Br J Dermatol. 2005;153(2):346-51.