Psoriasis: Marching Further?
Psoriasis vulgaris is a chronic inflammatory skin disorder associated with systemic comorbidities, including arthritis, cardiovascular disease, renal disease, diabetes mellitus, and metabolic syndrome.[1] This has led to the concept of the "psoriatic march": psoriasis as a chronic inflammatory condition driving inflammatory disease in multiple organ systems.[2,3,4] Psoriasis affects up to 10% of adults worldwide, making awareness of comorbidities an important part of patient care. Knowledge of these associations will lead clinicians to establish a pertinent review of systems and order appropriate laboratory tests (eg, fasting blood glucose and lipid profile).
To date, several studies in primarily white populations have suggested an association between psoriasis and inflammatory bowel disease (IBD)—both Crohn disease and ulcerative colitis.[5,6] Elevated serum and tissue levels of proinflammatory cytokines, including tumor necrosis factor alpha, IL-12, and IL-23, are found in both psoriasis and IBD, and targeted blockade of these cytokines (or cytokine receptors) often yields dramatic improvement in both conditions.[7,8]
To further explore the strength of any association between psoriasis (vulgaris and arthritis) and IBD, Fu and colleagues[9]performed a meta-analysis of five case-control or cross-sectional studies (n = 1,826,777) and four cohort studies (n = 5,967,410). Eligible studies were pulled from a larger pool using stringency criteria outlined by the Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) and Meta-analysis of Observational Studies in Epidemiology (MOOSE) guidelines.
