Phenome-wide Longitudinal Association Study of Hospital-recorded Comorbidity in Psoriasis

BACKGROUND: International guidelines recommend screening individuals with psoriasis, a common chronic inflammatory skin condition, for a range of conditions across the spectrum of human disease. Despite this, gaps may remain within our knowledge of the full breadth of comorbidity in psoriasis. OBJECTIVES: To perform a phenome-wide longitudinal association study of psoriasis and its comorbidities. METHOD: We conducted cohort studies (matched for age, sex and general practice) for each block (group of related conditions) of outcomes within the International Classification of Diseases - Clinical Modification (10th ed.) using Clinical Practice Research Datalink Aurum primary care data linked to secondary care Hospital Episode Statistics (to define ICD outcomes) within the United Kingdom. We evaluated the association between psoriasis and outcomes in the first year of diagnosis and in the subsequent period. We estimated hazard ratios (HR) with 99% confidence intervals from Cox regression, with covariate models adjusted for alcohol, smoking, BMI and measures of social deprivation. RESULTS: We compared 320,220 individuals with psoriasis to 1,706,424 matched individuals. In 225 ICD blocks evaluated, psoriasis was associated with numerous outcomes across organ systems. Strong, non-dermatological associations in the long-term included liver disease (HR 1.47 [1.42-1.51], RD 1.16), substance (including alcohol and tobacco) misuse (HR 1.26 [1.25-1.28], RD 3.27) and other respiratory diseases principally affecting the interstitium (HR 1.33 [1.27-1.40], RD 0.31). CONCLUSION: This study provides evidence of association between psoriasis and a range of comorbidity and may serve to generate hypotheses on previously underappreciated associations.