Association of psoriasis with asthma: A systematic review and meta-analysis of observational studies

Background: Psoriasis is a chronic inflammatory skin disease that has been associated with various inflammatory comorbidities such as cardiovascular disease and uveitis. Asthma involves inflammation of the airway. The two diseases share cytokine-mediated inflammatory mechanisms. Objectives: The main objective of the study was to examine the association of psoriasis with asthma. Methods: We conducted a systematic review and meta-analysis of observational studies that examined the association of psoriasis with asthma. We searched MEDLINE, Embase, and CENTRAL from inception to May 2, 2019 for relevant case–control, cross-sectional, or cohort studies. The risk of bias of included studies was assessed by using the Newcastle–Ottawa Scale. The random-effects model meta-analysis was used to calculate the odds ratio (OR) for case–control/cross-sectional studies and hazard ratio (HR) for cohort studies. Results: We included six case–control/cross-sectional (one case–control and five cross-sectional studies) and one cohort studies. Three studies were rated with a high risk of bias in case definition, representativeness of the cases, selection of controls, definition of controls, and ascertainment of exposure. Psoriasis was associated with significantly increased odds (OR 1.29; 95% confidence interval [CI] 1.20‒1.37) and risk (HR 1.38; 95% CI 1.23‒1.54) for asthma. A subgroup analysis revealed increased odds for asthma in both pediatric and adult patients with psoriasis (pooled OR being 1.24 [95% CI 1.10‒1.41] and OR 1.38 [95% CI 1.27‒1.50], respectively). Conclusion: The current evidence indicates a significant association of psoriasis with asthma. When psoriasis patients present with respiratory symptoms for shortness of breath, wheezing, and chest tightness, referral to pulmonologist may be considered.