Incidence Rate of Chronic Kidney Disease and Its Association with Long-Term Nonsteroidal Anti-Inflammatory Drug Use in Ankylosing Spondylitis: A Nationwide Population-Based Study.

Aim: Ankylosing spondylitis (AS) predominantly affects the spine and sacroiliac joints, with rare renal involvement. We investigated the incidence rate and risk factors for chronic kidney disease (CKD) in patients with AS and its relationship with long-term nonsteroidal anti-inflammatory drug (NSAID) use. Methods: We retrospectively analyzed data of patients diagnosed with AS from the Korean National Health Insurance service. The 3-month, 6-month, and 1-year Assessment of SpondyloArthritis International Society (ASAS) NSAID Intake Scores were categorized into four groups, as follows: =0, >0 and <= 33.3, 33.3-66.6, and >66.6. Results: Of the 12 000 patients with AS, 150 were identified with CKD, and the incidence rate was 4.64 per 10 000 patient-years. Factors significantly associated with CKD included age >= 60 years, Charlson Comorbidity Index, hypertension, and diabetes mellitus. In the nested case-control analysis, among the ASAS NSAIDs Intake Scores for 0-365 days from diagnosis, the >= 66.6 group had a significantly lower odds ratio than those of the =0 group. Conclusion: The present study established the incidence rate of CKD in Korean patients with AS. Though older age and comorbidities were found to be associated with a higher CKD risk, long-term NSAID use was associated with a lower risk. Therefore, the optimal use of NSAIDs in inflammatory diseases requires extensive research.