Reverse Epidemiology for Lipid Disorders in Hemodialysis-Dependent Patients: Role of Dilutional Hypolipidemia

INTRODUCTION: Atherosclerotic cardiovascular disease is a major cause of mortality and morbidity in dialysis patients. Compared to general population, dialysis patients have lower lipid levels and higher vascular events. This paradox is popularly known as reverse epidemiology. Present study is an attempt to understand reasons for low lipids in dialysis patients. SUBJECTS AND METHODS: This was a prospective observational multicentric study involving three stages across six dialysis units with Care Hospitals, Hyderabad. Maintenance hemodialysis patients were studied with fasting lipid profiles [TC, LDL-c, HDL-c, and TG], pre- and post-dialysis blood lipids and effluent water lipid profiles. Other parameters studied were use of statins, interdialytic weight gain, and ultrafiltration. All patients had uniform dialysis protocols regarding filter used and dialysis duration. RESULTS: Of the 91 patients studied, we observed significant rise in post-dialysis TC, LDL, and HDL [P < 0.01] and lower lipids [P < 0.01] just before the next dialysis. Lipids were least filtered across the membrane except HDL, which was found in effluent water for more than 60% of patients. Single use of dialyser was associated with higher rise in post dialysis lipids as well as HDL getting filtered in effluent [P = 0.24]. Rosuvastatin was associated with lower lipid values [P = 0.08] and BMI [P = 0.19]. CONCLUSIONS: Low lipid levels in dialysis patients are due to dilutional hypolipidemia and needs correction with an equation proposed in present study. Corrected lipids should be used for risk stratification and deploying treatment.