The psoriasis – Type 2 diabetes connection

More studies are needed in order to better understand the relationship between psoriasis and Type 2 diabetes as well as other comorbid conditions. (nikkikii - stock.adobe.com)

Psoriasis has been strongly linked to metabolic and Type 2 diabetes, but the exact relationship between psoriasis and Type 2 diabetes remains ambiguous.

Jesper Holm, M.D. and colleagues from the Department of Dermato-Venereology at Bispebjerg Hospital in Copenhagen Denmark studied the link between Type 2 diabetes and psoriasis to better understand the pathophysiology, and provide a better understanding of the link between the two diseases.

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This study was performed as a systematic review, in which articles indexed in PubMed were searched for using the keywords “psoriasis,” “diabetes,” “risk,” “link” and “association.” The review included all clinical literature on this topic in English from case reports to randomized controlled trials. Reviews, however, were excluded.

Researchers analyzed 15 epidemiologic psoriasis cohorts. The average prevalence of Type 2 diabetes across psoriasis cohorts was 11.6%, but there was no apparent association between Type 2 diabetes prevalence and mean patient age (n=15, P=0.183) across the identified cohorts. The prevalence of Type 2 diabetes in psoriasis patients compared to controls was examined in 11 studies; all the 11 studies showed an increased prevalence of Type 2 diabetes compared to controls. The authors found however, that there was no correlation between Type 2 diabetes prevalence and psoriasis severity. Across the psoriasis cohorts there was no correlation between Type 2 diabetes prevalence and mean Psoriasis Area and Severity Index (PASI) (n=5, P=0.188).

Many patients suffering from Psoriasis also suffer from psoriatic arthritis. Some of the reviewed studies showed that there was an increased prevalence of Type 2 diabetes in patients with both psoriasis and psoriatic arthritis. However, several studies showed no difference in the risk or prevalence of Type 2 diabetes in patients with psoriasis and psoriatic arthritis compared to patients with psoriasis alone. In addition several studies showed that other cardiovascular risk factors such as metabolic syndrome were significantly increased in patients with psoriasis.

The postulated overlap in the pathophysiology that connects psoriasis to Type 2 diabetes was also reviewed by the authors. One mechanism connecting these diseases is related to miRNA in cholesterol efflux  that is upregulated in psoriasis skin lesions. Another postulated component that links the two diseases is clusterin, a lipid transport protein that is increased in psoriasis patients. The genetic mechanism has not been elucidated.

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Other comorbidities are also more prevalent in psoriasis. There are conflicting reports regarding whether there is an increase in cardiovascular mortality in patients with psoriasis. Parisi et al suggests that the increase in cardiovascular mortality is related to known risk factors as opposed to psoriasis. Still multiple studies suggest and increased prevalence of serious cardiovascular disease in patients with psoriasis.

The authors conclude that more studies are needed in order to better understand the relationship between psoriasis and Type 2 diabetes as well as other comorbid conditions. For the time being, they advise control of psoriasis as well as judicious intervention of usual cardiovascular risk factors.

References:

Holm JG, Thomsen SF. Type 2 diabetes and psoriasis: links and risks. Psoriasis (Auckl). 2019;9:1-6.