relationships between serum lipoproteins and apolipoproteins A-1 nad B levels in hyperlipidemic patients in Kuwait

ABSTRACT

It has been suggested that assaying blood levels of apolipoproteins [apo] A-1 and B could constitute a better alternative to measuring HDL and LDL levels in the routine assessment of lipid disorders. We have therefore evaluated the relationships between the serum levels of apo A-1 and B and the lipoproteins HDL and LDL in 214 hyperlipidaemic subjects [46 diabetic, 168 nondiabetic] and 69 normolipidaemic healthy subjects resident in Kuwait. There were no significant differences in age between the groups. The levels of total cholesterol [TC], triglycerides [TG], HDL, LDL, and apo A-1 and B showed the expected differences between the normo- and hyper-lipidaemic groups [diabetic and nondiabetic]. In the hyperlipidaemic subjects as a whole, there were significant correlations between apo A 1 and HDL [r 0.52, p<0.001] and between apo B and TC [r 0.65] TG [r 0.38] and LDL [r 0.66] all p <0.001 These relationships were somewhat weaker than seen in the normnolipidaemic subjects [apo A-1/HDL r 0.76, apo B/LDL, r 0.81, all p<0.001]. The diabetic hyperlipidaemic subjects also had somewhat weaker correlations [apo A-1/HDL, r 0.56, apo B/LDL, r 0.60, p < 0.001] than the nondiabetic hyperlipidaemic subjects [apo A-1/HDL, r 0.60, apo B/LDL, r 0.68, p < 0.00]. Using decision limits proposed for apo B [>1 20g/L] LDL [3.4 mmol/L], apo A-1 [< 1 20gfL] and HDL [<0 9 mmol/L], the percentages of hyperlipidaemic subjects with atherogenic values did not satisfactorily correspond for apo A-1 vs. HDL, but corresponded better for apo B vs. LDL, both for the diabetic and nondiabetic subjects. These observations suggest that, while there are clearly significant relationships between plasma levels of apo A-1and B and the lipoproteins HDL and LDL, the strength of those relationships appear better in normo- as compared to hyper-lipidaemic patients. Care should therefore be taken in using measurements of apolipoproteins and lipoproteins interchangeably in the routine management of hyperlipidaemic patients. Rather, both measurements should be made simultaneously and used to complement each other in the overall assessment of need for therapy in these patients