Incidence rate and risk factors for interstitial nephritis in patients with ankylosing spondylitis: a nationwide population-based study
10.4078/jrd.2025.0096
- Author:
Subin HWANG
;
Ye-Jee KIM
;
Soo Min AHN
;
Bon San KOO
- Publication Type:Original Article
- From:Journal of Rheumatic Diseases
2026;33(2):102-110
- CountryRepublic of Korea
- Language:English
-
Abstract:
Objective:In this study, we aimed to investigate the incidence and risk factors for interstitial nephritis in patients with ankylosing spondylitis (AS).
Methods:We retrospectively analyzed the claims records of patients diagnosed with AS in Korea’s Health Insurance Review and Assessment Service Database between 2016 and 2019. The Assessment of Spondyloarthritis International Society nonsteroidal anti-inflammatory drugs (NSAIDs) intake score was used to calculate the NSAID dosage over 1 year after AS diagnosis. The incidence rate of interstitial kidney disease was calculated as the number of events per 1,000 person-years. The risks associated with sex, age, Charlson Comorbidity Index, comorbidities, and concomitant medications were assessed using the Cox proportional hazards model, with results presented as hazard ratios (HRs) and 95% confidence intervals (CIs).
Results:In total, 11,749 patients with AS were included in this study. Of these, 79 patients had interstitial nephritis, with an incidence rate of 2.50 per 1,000 person-years. In multivariable analysis, female sex (HR, 2.44; 95% CI, 1.56~3.83), hypertension (HR, 2.08; 95% CI, 1.15~3.76), and renal failure (HR, 3.70; 95% CI, 1.30~10.55) showed significant associations. However, NSAID use in the first year after AS diagnosis was not associated with interstitial nephritis occurrence.
Conclusion:The incidence of interstitial nephritis in patients with AS was 2.50 per 1,000 person-years, with female sex and comorbidities identified as significant risk factors. However, NSAID use during the first year after AS diagnosis was not associated with interstitial nephritis development.
