Proteinuria and Psoriasis Risk: A Nationwide Population-Based Study.

Psoriasis, a chronic inflammatory dermatosis, has been associated with chronic kidney disease or end-stage renal disease. However, the association of the changes or amount of proteinuria with psoriasis development has not been evaluated. Using the Korean National Health Screening database, we assessed psoriasis development until 2018 in 6,576,851 Koreans who underwent health examinations in 2009 and 2011. Psoriasis was defined using the International Classification of Diseases, 10th revision (ICD-10) code L40. The risk of psoriasis was evaluated according to change in proteinuria (never [Neg (no proteinuria)/Neg], new [Neg/Pos (proteinuria present)], past [Pos/Neg] and persistent [Pos/Pos] proteinuria) and the proteinuria amount. During a median 7.23-year follow-up, 162,468 (2.47%) individuals developed psoriasis. After adjustments, the hazard ratio (HR) for psoriasis was higher in the persistent proteinuria group (1.32 [1.24-1.40]) than in the never proteinuria group. The past proteinuria group showed better renal outcome (1.03 [1.00-1.07]) than the new (1.05 [1.01-1.07]) and never proteinuria (reference, 1.00) groups did. The amount of random urine proteinuria was associated with increased HR for psoriasis. Subgroup analyses for age, sex, estimated glomerular filtration rate (eGFR), hypertension and diabetes showed that the persistent proteinuria group had a higher risk of psoriasis than the never proteinuria group, especially at eGFR < 60 mL/min/1.73 m2. Persistent proteinuria is associated with psoriasis risk, and the proteinuria amount significantly affects psoriasis development.