Increased Risk of Renal Malignancy in Patients with Moderate to Severe Atopic Dermatitis

Background: Evidence for an association between atopic dermatitis (AD) and cancer is still insufficient. In particular, the association between the risk of renal malignancy and the severity of AD has not been thoroughly investigated. Objective: To investigate the risk of renal malignancy and determine the association between AD severity and cancer risk using data from the Korean National Health Insurance Service (KNHIS) database. Methods: We performed a population-based cohort study using the National Health Claims database from the NHIS in Korea. Results: We found a statistically significant association between AD and overall malignancy (for mild AD, hazard ratio (HR): 1.061, 95% confidence interval (CI): 1.006–1.118; for moderate to severe AD, HR: 1.061, 95% CI: 1.014–1.11) compared with the no AD group. The moderate to severe AD group showed a significantly increased risk for renal malignancy (adjusted HR: 1.533, 95% CI: 1.209–1.944) compared with the no AD group. Limitations: Patient inclusion is solely based on diagnostic codes. We had no data about drug use, genetic factors, or other medical history that could affect the cancer risk. Conclusion: In our large population-based cohort study, moderate to severe AD was associated with increased risk of renal malignancy. Regular check-ups for renal malignancy are recommended in this population.