Apo-B/apo-AI ratio: a better discriminator of coronary artery disease risk than other conventional lipid ratios in Indian patients with acute myocardial infarction.
BACKGROUND
Coronary artery disease (CAD) is a leading cause of morbidity and mortality in the developed world and is rapidly assuming epidemic proportions in developing countries including India. This has led to extensive research to determine the risk factors unique to this group which may predispose to the elevated risk of this disease. Important amongst them are lipoproteins, homocysteine, lipoprotein (a), pro-inflammatory cytokines etc. The following study was undertaken to evaluate the role of the apolipoprotein-B100 (apo-B)/apolipoprotein-AI (apo-AI) ratio as a predictor of CAD risk in the atherosclerosis-prone Indian population, as compared to other conventional lipid ratios.


METHODS
The study group comprised 100 clinically assessed patients with acute myocardial infarction (AMI) diagnosed on electrocardiographic and biochemical criteria and 100 age-matched healthy control subjects. Apo-B and apo-AI levels were estimated by the immunoturbidimetric method, using kits from Randox, UK. Lipid profile was determined using standard enzymatic methods. The exponential regression coefficient beta was calculated for total cholesterol/high-density lipoprotein cholesterol (TC/HDL), TC-HDL/HDL, low-density lipoprotein ( LDL) cholesterol/HDL and apo-B/apo-AI ratios.


RESULTS
The TC/HDL ratio was 5.15 +/- 1.7 and 3.45 +/- 0.87 in patients with AMI and control subjects, respectively (P< 0.001). The TC-HDL/HDL ratio was 4.61 +/- 2.6 and 2.22 +/- 1.14 in the patients with AMI and the control subjects (P <0.001). The LDL/HDL ratio was 3.32 +/- 1.5 in the AMI patients and 1.84 +/- 0.78 in the control subjects (P < 0.001); whilst the apo-B/apo-AI ratio in the patients with AMI was 0.96 +/- 0.30 and 0.71 +/- 0.20 in the control subjects (P <0.001). The exponential value of the regression coefficient beta (Exp [beta]) for apo-B/apo-AI ratio was 111.9, as compared to 4.4 for the LDL/HDL ratio, 3.5 for the TC/HDL ratio and 2.2 for the TC-HDL/HDL ratio, though all the lipid ratios were significantly higher in cases than in control subjects.


CONCLUSIONS
Our findings suggest that the apo-B/apo-AI ratio is a better discriminator of CAD risk in the atherosclerosis-prone Indian population, than any of the conventional lipid ratios. The reduction of value of the apo-B/apo-AI ratio may drastically decrease the risk for CAD. Hence, the apo-B/apo-AI ratio may be suggested as an alternative to other lipid ratios fo risk assessment in patients with CAD.
Goswami
Binita
B
Department of Biochemistry, Maulana Azad Medical College, New Delhi, India. binitadr@yahoo.co.in
Rajappa
Medha
M
Mallika
Venkatesan
V
Kumar
Suresh
S
Shukla
Deepak Kumar
DK
D000328:Adult; D016632:Apolipoprotein A-I / Q000097:blood*; D001055:Apolipoproteins B / Q000097:blood*; D015897:Comorbidity; D003324:Coronary Artery Disease / Q000097:blood* / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007194:India; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood* / Q000453:epidemiology; D018570:Risk Assessment; D044465:White People
D016632:Apolipoprotein A-I; D001055:Apolipoproteins B