Blood lead levels association with 18-month all-cause mortality in patients with chronic peritoneal dialysis

Background. The clinical significance of blood lead levels (BLLs) in chronic peritoneal dialysis (CPD) patients was undetermined prior to this study.Methods. A total of 315 patients on CPD were included in this 18-month prospective study. BLLs measured at baseline were categorized according to a BLL tertile of high (>8.66g/dL), middle (5.62-8.66g/dL) and low (<5.62g/dL) for cross-sectional analyses. Mortality and cause of death were recorded for longitudinal analyses.Results. At baseline, patients with high BLLs had a trend of higher parathyroid hormone and lower residual renal function than patients in other groups. Stepwise multiple regression analysis found that parathyroid hormone positively correlated and residual renal function negatively correlated with logarithmic-transformed BLLs in CPD patients after other confounders were adjusted. At the end of follow-up, 37 (11.7%) patients had died. Kaplan-Meier analysis showed that patients with high BLLs had greater mortality than those with middle and low BLLs (P=0.008). Cox multivariate analysis showed that, using the low BLL group as the reference, basal high BLLs (hazard ratio [HR]=3.745, 95% confidence interval [95% CI]=1.218-11.494, P=0.001) and middle BLLs (HR=1.867, 95% CI=1.618-2.567, P=0.001) were associated with increased HR for all-cause mortality for CPD patients. There is a significant trend (P<0.001) of HR for mortality trend tests among the three study groups.Conclusions. BLLs are associated with residual renal function and hyperparathyroidism and are related to increased HR for all-cause 18-month mortality in CPD patients.