The relationship between long-term use of nonsteroidal anti-inflammatory drugs and kidney function in patients with ankylosing spondylitis.

Objective: Although nonsteroidal anti-inflammatory drugs (NSAIDs) are the first-line treatment for ankylosing spondylitis (AS), their effect on kidney function remains unclear. This longitudinal study investigated the correlation between long-term NSAID use and kidney function in patients with AS using electronic medical records. Methods: The electronic medical records of 1,280 patients with AS collected from a single center between January 2001 and December 2018 were reviewed. The Assessment of Spondyloarthritis International Society (ASAS) NSAID Intake Score was used to determine the cumulative dose of all NSAIDs prescribed for a different time intervals. Each ASAS NSAID Intake Score was obtained for intervals of 6 months, 1 year, 2 years, 3 years, 5 years, and 10 years. The correlation between the ASAS NSAID Intake Score and final estimated glomerular filtration rate (eGFR) for each interval was investigated. Results: The mean ASAS Intake Scores for 6-month, 1-year, 2-year, 3-year, 5-year, and 10-year intervals were 55.30, 49.28, 44.84, 44.14, 44.61, and 41.17, respectively. At each interval, the pearson correlation coefficients were -0.018 (95% CI -0.031 to -0.006, p=0.004), -0.021 (95% CI -0.039 to -0.004, p=0.018), -0.045 (95% CI -0.071 to -0.019, p=0.001), -0.069 (95% CI -0.102 to -0.037, p<0.001), -0.070 (95% CI -0.114 to -0.026, p=0.002), -0.019 (95% CI -0.099 to 0.062, p=0.645), respectively. There was a very weak negative relationship between ASAS Intake Score and eGFR at each interval. Conclusion: Long-term NSAID use did not correlate with kidney function based on real-world data in patients with AS.