Significance of the decreased risk of dialysis-related amyloidosis now proven by results from Japanese nationwide surveys in 1998 and 2010

Abstract

Background Although dialysis technology greatly improved in recent years, it remained unclear whether those improvements helped decrease the incidence of dialysis-related amyloidosis (DRA). Accordingly, we retrospectively compared the incidence of first-time carpal tunnel surgery (CTS) - as proxy for DRA onset - in two cohorts of chronic hemodialysis patients, with the second cohort studied after dialysis methods (especially dialyzate quality control) had greatly improved. Methods We used the 1998 and 2010 Japan Renal Data Registries to compare crude risk of first-time CTS the following year. After adjusting for patient background and laboratory data, odds ratios (ORs) for CTS in the whole cohorts and the populations matched by propensity score (PS) for hemodialysis and hemodiafiltration were calculated at a 95% confidence interval. Results Of note, 2 02 726 patients were analyzed. In the 1998 cohort, 1.77% experienced first-time CTS compared with 1.30% of the 2010 cohort (P < 0.001); with 2010 as referent, the adjusted 1998 OR was 2.22 (1.68-2.95). Both crude risks and adjusted ORs were analyzed by dialysis vintage, age, pre-dialysis β2-microglobulin (β2m) and β2m clearance, risk of CTS trending 1.5-2.0 higher in 1998 than 2010. The reduction was most prominent in patients with longer dialysis vintage, patients who were younger, and those with lower pre-dialysis β2m levels. Similar results were obtained by PS-matched analysis. We also found that β2m clearance >80% may reduce risk of CTS. Conclusions The incidence of first-time CTS as proxy for DRA decreased significantly from 1998 to 2010. Several factors may have contributed to this decrease, including improved dialysis methods.