Associated comorbidities in psoriasis and inflammatory bowel disease

BACKGROUND: The association between psoriasis and inflammatory bowel disease (IBD) has been previously reported although a great deal remains unknown about associated comorbidities. OBJECTIVES: The aim of this study was to examine comorbidities in individuals diagnosed with both psoriasis and IBD, and to compare those with individuals diagnosed with psoriasis-only. We also looked at differences within the IBD group by clearly defining that cohort. METHODS: We included 146 patients diagnosed with both psoriasis and IBD and 146 controls diagnosed of psoriasis-only without previous records of IBD, matched by gender, ethnicity and age (±5 years). Patients were obtained from the research patient data repository of Brigham and Women's Hospital (BWH) and Massachusetts General Hospital. Controls were obtained from the psoriatic arthritis and psoriasis follow-up study (PAFS) at BWH. The comparison between the two groups included socio-demographics, comorbidities and laboratory inflammation parameters. RESULTS: Compared to individuals with psoriasis-only, patients with both psoriasis and IBD had significantly higher rates of autoimmune thyroiditis (2.1% vs. 6.8%), hepatitis (0.7 vs. 6.2%) and diabetes (11.0% vs. 26.7%). In addition, of the 146 patients with psoriasis and IBD, 60 (41.1%) were diagnosed with seronegative arthritis. The average C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) of the last visits in our clinics were significantly elevated compared to the individuals with psoriasis-only (ESR, 33.5 vs. 4.0 mm/h; CRP, 9.1 vs. 2.3 mg/L; both P-values <0.0001). CONCLUSIONS: We found that patients with both, psoriasis and IBD have a number of further associated comorbidities, some at significantly higher levels than individuals with psoriasis-only. Common inflammatory pathways and genetic predispositions for specific patterns in the immune response may play an important role in the evolution of associated conditions.