[High-density-lipoprotein and renal insufficiency (author's transl)]

Disturbances in lipid metabolism and accelerated atherosclerosis are well-known phenomena of chronic renal insufficiency. The disturbance in lipid metabolism has been repeatedly described as secondary type IV hyperlipoproteinemia according to the classification of Fredrickson. The classification of Fredrickson, however, does not take into account the role of the alpha-lipoproteins (the HDL lipoproteins and HDL cholesterol). Hence, HDL cholesterol was determined and correlated to other routine parameters of lipid metabolism in 66 patients with different degrees of renal insufficiency. Furthermore, an intravenous fat tolerance test was performed in 14 patients with terminal renal insufficiency. Beside the well-known hypertriglyceridemia with cholesterol values near the upper limits of normal, a significant reduction in HDL cholesterol was found, showing a significant inverse correlation to plasma creatinine values. Patients with advanced or terminal renal insufficiency additionally showed a significant inverse correlation between HDL cholesterol and plasma triglycerides. The disappearance rate of intravenously administered fat emulsion (which corresponds to the clearance rate of chylomicrons and VLDL) was diminished in azotaemic patients, showing a significant inverse correlation between HDL cholesterol and disappearance rate in the intravenous FTT. Beside hypertriglyceridemia, the diminished HDL cholesterol values represent an additional risk factor for the genesis of accelerated atherosclerosis. The diminished k value demonstrates a diminished activity of lipoprotein lipase as cause of hypertriglyceridemia, whereby the positive correlation between the k value and HDL cholesterol and the inverse correlation between HDL cholesterol and triglycerides suggest a causal relationship between the decreased activity of lipoprotein lipase and diminished HDL cholesterol levels.