Renal dysfunction causes dyslipidemia, and the progression of kidney disease is associated with treatment-requiring lipid disorders. However, there is little data on the association between the severity of dyslipidemia and various treatment modalities with renal function. A total of n = 214 prevalent patients from a lipidology and nephrology practice were investigated in an unicentric cross-sectional study and divided into 4 groups based on the severity and therapeutic regimen of an existing lipid metabolism disorder: a lipid apheresis-treated group (LA), a drug-treated group (MG), a control group (CG) that included patients with lipid disorder not needing any treatment, and a diabetes group that comprised all diabetes patients. We examined fat metabolism parameters, renal parameters and urinary protein excretion, and compared these between study groups. Lipid apheresis therapy leads to the effective lowering of low density lipoprotein-concentration and to a reduction in the presumably protective high density lipoprotein-concentration. We found that S-crea was significantly higher in the LA, MG, and diabetes group than in the CG, while electronic glomerular filtration rate (eGFR) was correspondingly lower. On the other hand, proteinuria was not elevated in the LA- and MG-groups compared to CG. Multiple regression analysis revealed lipoprotein (a) values as a predictor for eGFR decline and increased proteinuria. Elevated lipoprotein (a) levels are associated with decreased eGFR and worse proteinuria, highlighting that regular monitoring and effective treatment, to date especially lipid apheresis, are of utmost importance to mitigate detrimental effects on renal function.