The association of lipid-modifying medications with mortality in patients on long-term peritoneal dialysis

Background: The effect of lipid-lowering therapy on clinical outcomes in peritoneal dialysis patients has not been carefully addressed. Study Design: Secondary analysis of a retrospective cohort study. Setting & Participants: Data from 1,053 incident peritoneal dialysis patients from the US Renal Data System prospective Dialysis Morbidity and Mortality Wave 2 study. Predictor: Use of lipid-modifying medications (93% statins, 7% other medications). Outcomes & Measurements: Cox regression with propensity score adjustment was used to evaluate time to cardiovascular or all-cause mortality during a 2-year follow-up period. Subgroups based on predefined cutoff values for serum total cholesterol or triglycerides, presence of diabetes, and comorbidity index were analyzed separately. Results: Use of lipid-modifying medications was associated with decreased all-cause (hazard ratio [HR], 0.74; 95% confidence interval, 0.56 to 0.98) and cardiovascular (HR, 0.67; 95% confidence interval, 0.47 to 0.95) mortality compared with no use of lipid-modifying medications. In subgroup analyses, use of lipid-modifying medications was associated with decreased all-cause mortality (HR, 0.46; 95% confidence interval, 0.22 to 0.95) in the subgroups with cholesterol levels of 226 to 275 mg/dL (HR, 0.27; 95% confidence interval, 0.09 to 0.80) and cholesterol levels greater than 275 mg/dL and cardiovascular mortality (HR, 0.31; 95% confidence interval, 0.11 to 0.85) in the subgroup with cholesterol levels of 226 to 275 mg/dL. Use of lipid-modifying medications also was associated with decreased cardiovascular mortality (HR, 0.64; 95% confidence interval, 0.41 to 0.99) in patients with diabetes and decreased all-cause (HR, 0.65; 95% confidence interval, 0.45 to 0.94) and cardiovascular mortality (HR, 0.55; 95% confidence interval, 0.35 to 0.87) in those with Charlson Comorbidity Index score higher than 2. Limitations: Observational study with retrospective design. Considerable amount of missing data and limited amount of information for the extreme values of cholesterol and triglycerides. Conclusions: These observational data suggest that lipid-modifying medication therapy may be associated with improved clinical outcomes in peritoneal dialysis patients.