Is psoriasis associated with dementia or cognitive impairment? A Critically Appraised Topic*

Clinical question: Is psoriasis associated with dementia or cognitive impairment?. Background: Psoriasis is a multisystemic inflammatory disorder that has an unclear association with cognitive dysfunction. Objectives: To conduct a Critically Appraised Topic that synthesizes the results from relevant observational studies. Methods: A systematic literature search of PubMed and Embase was conducted on 12 July 2019 to identify case–control, cross-sectional or cohort studies that investigated the association between psoriasis and cognitive impairment or dementia. Risk of bias was assessed for each study, and the results presented in a narrative synthesis. Results: Eleven studies were included for critical appraisal. Of the 11 studies, 10 compared a total of 16 574 psoriasis cases with over 45 078 controls for risk of dementia or cognitive impairment. One of the 11 studies evaluated 7118 patients with dementia for odds of psoriasis compared with 21 354 controls. Six studies were assessed to have higher risk of bias. Nine of the 11 included studies found a significant positive association between the two diseases, one study a null association, and one study an inverse association. Discussion and recommendation: Most of the 11 included studies found a positive association between psoriasis and either mild cognitive impairment or dementia. Brief cognitive assessments have been suggested to screen older patients with psoriasis who present with subjective cognitive complaints.