THU0692 Risk of end-stage renal disease requiring dialysis in ankylosing spondylitis patients starting medical therapy: a nationwide, population-based, cohort study
Authors: H.-H. Chen, D.-Y. Chen, T.-Y. Hsieh, K.-L. Lai, Y.-M. Chen, C.-W. Tseng, C.-T. Lin
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> From the year 2000 Taiwan has had the highest incidence and prevalence of end-stage renal disease (ESRD) among the regions investigated by the US Renal Data System. Also, previous studies had suggested a possible association between IgA nephropathy and ankylosing spondylitis (AS) because an increased prevalence of microscopic hematuria and a higher proportion of elevated serum IgA levels were found in AS patients. However, whether the risk of ESRD was increased in treated AS patients or not is still unknown. <h3>Objectives</h3> To examine the risk of ESRD requiring dialysis in patients with AS who started medical therapy. <h3>Methods</h3> Using 2003–2012 claims data from the Taiwanese National Health Insurance Research Database, we identified 38,259 AS patients who received at least 3 courses of AS-related medical therapy (i.e., non-steroidal anti-inflammatory drugs, methotrexate, salazopyrine or corticosteroid) and started therapy from 2005 to 2012. The first date of medical therapy was defined as the index date. After excluding those who had a history of chronic renal disease (ICD9-CM 585, 586) or receiving dialysis before the index date, we identified 37 070 newly-treated AS cases. We randomly selected 3 70 700 non-AS individuals matching (1:10) AS cases for age, sex and the year of the index date without a history of chronic renal failure or dialysis before the index date. After adjusting for age, sex, moderate to severe renal disease, diabetes mellitus, hypertension, and annual cumulative defined daily dose (cDDDs) of traditional non-steroidal anti-inflammatory drugs (NSAIDs), selective cyclooxygenase-2 inhibitors (COX2i), and preferential COX2i, we calculated the adjusted hazard ratios (aHRs) with 95% confidence intervals (CIs) using the Cox proportional hazard model to quantify the risk of ESRD in AS patients compared with non-AS controls. We re-selected 6,621 AS patients and 6621 non-AS subjects by further matching (1:1) for cDDDs of three groups of NSAIDs to re-estimate the aHRs for ESRD. <h3>Results</h3> 51 (0.14%) of 37,070 AS patients and 1,17 (0.38%) of non-AS individuals developed ESRD after a follow-up of 1 58 846 and 1,707,757 person-years respectively. The aHR for ESRD was 0.4 (0.30–0.54) in AS patients compared with non-AS individuals. However, after further matching for cDDDs of NSAIDs, the aHR of ESRD was 0.80 (0.34–1.86). Significant risk factors included diabetes mellitus, hypertension, renal disease, and use of COX2i. <h3>Conclusions</h3> The risk of ESRD was not significantly different between treated AS patients and age, sex, index date, and NSAIDs use matched non-AS individuals. <h3>References</h3> [1] Basthesda MD. U.S. Renal Data System USRDS 2007 Annual Data Report: Atlas of Chronic Kidney Disease and End-Stage Renal Disease in the United States. National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases2007. [2] Lai KN, Li PK, Hawkins B, et al. IgA nephropathy associated with ankylosing spondylitis: occurrence in women as well as in men. Ann Rheum Dis1989;48:435–7. <h3>Acknowledgements</h3> The authors would like to thank the Biostatistics Task Force of Taichung Veterans General Hospital, Taichung, Taiwan, ROC for statistical support. <h3>Disclosure of Interest</h3> None declared