Increased risk of glomerulonephritis and chronic kidney disease in relation to the severity of psoriasis, concomitant medication, and comorbidity: a nationwide population-based cohort study

Few studies have examined the association between psoriasis and glomerulonephritis (GN) as well as chronic kidney disease (CKD). To determine the risk of CKD in patients with psoriasis and evaluate the impact of the severity of psoriasis, comorbidities and concomitant drugs on the risk of GN and CKD in patients with psoriasis. We identified 4344 patients with psoriasis for the study cohort and randomly selected 13 032 subjects as a control cohort. Each subject was individually followed for up for 5 years to identify those who subsequently developed GN and CKD. After adjustment for traditional CKD risk factors, psoriasis was found to be independently associated with an increased risk of CKD during the follow‐up period [hazard ratio (HR) 1·28; 95% confidence interval (CI) 1·14–1·44]. The increased incidence of GN in patients with psoriasis (HR 1·50, 95% CI 1·24–1·81) may contribute to the positive association between psoriasis and CKD. Patients with mild and severe psoriasis had an increased risk of CKD and GN compared with the control cohort; the risk increased with severity. Patients with psoriasis and arthritis exhibited a higher risk of CKD than patients without arthritis (HR 1·62 vs. 1·26). Among drugs, nonsteroidal anti‐inflammatory drugs (NSAIDs) have the strongest association with CKD in patients with psoriasis (adjusted odds ratio 1·69, 95% CI 1·14–2·49). Psoriasis was associated with a higher risk of developing CKD and GN. High severity, psoriatic arthritis involvement and concomitant NSAIDs use further increased the risk of CKD in patients with psoriasis.