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 De-cember 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.