Studies on the nature and causes of hyperlipidaemia in uraemia, maintenance dialysis and renal transplantation.

Fasting serum triglyceride and cholesterol measurements, and lipoprotein characterization by ultracentrifugation, were performed in four groups of patients with chronic renal disease (uraemic, short- and long-term haemodialysis and renal transplant recipients) and the results compared with those obtained from age- and sex-matched control subjects. Basal insulin and growth hormone levels, and serum creatinine and albumin concentrations were measured in, and detailed dietary histories taken from patients in each group. The predominant lipid abnormalities were hypertriglyceridaemia and increased very low density lipoproteins (type IV hyperlipoproteinaemia) in both uraemic and haemodialysis patients. Following renal transplantation, a different pattern of hyperlipidaemia was found. Hypercholesterolaemia was more common and hypertriglyceridaemia less common than in the uraemic and haemodialysis group. The lipoprotein abnormalities were increased low density and/or very low density lipoproteins, with types IIa IIb and IV hyperlipoproteinaemia occurring equally frequently. In uraemic and haemodialysis patients, the proportion of carbohydrate in the diet was high, and may have played a role in the genesis of hypertriglyceridaemia. There was a positive correlation between relative body weight and serum triglyceride in the long-term dialysis group. In renal allograft recipients hypertriglyceridaemia could be attributed, at least in part, to obesity, prednisone dosage and the degree of impairment of graft function. The aetiology of hypercholesterolaemia in the transplant recipients was unclear. Neither basal insulin nor growth hormone levels were elevated in any patient group. Uraemic hypertriglyceridaemia is a clearly defined and well documented metabolic abnormality which is not corrected by dialysis. Post-transplantation hyperlipidaemia however, is a condition of variable presentation and multifactorial aetiology.