A tertiary care hospital-based study of conventional risk factors including lipid profile in proven coronary artery disease

Abstract

Background: The prevalence and mortality rates of coronary artery disease have been known to be higher in the Indian than the Western population. Most data on lipid levels in Indians have been obtained from studies on migrant Asian Indians. There are insufficient data on lipid profile and other conventional risk factors in Indian patients living within India.

Methods and results: The study included 2656 consecutive patients who underwent coronary angiography between March 1998 and February 2002. Of these, 2399 subjects had angiographically proven coronary artery disease (group 1) while 257 had normal coronary arteries (group 2). Lipid values were measured in the fasting state on the morning the coronary angiography was done. Patients receiving lipid-lowering agents, those having renal, hepatic or thyroid disorders, patients presenting within 8 weeks after acute myocardial infarction, and patients who were taking noncardiac drugs that affect the lipid profile were excluded from the study. Other conventional risk factors were also recorded. In subjects with coronary artery disease and normal coronary arteries, the levels of mean total cholesterol recorded were 178.5+/-42.1 mg/dl v. 154.1+/-40.2 mg/dl (p<0.001), high-density lipoprotein cholesterol 30.6+/-9 mg/dl v. 27.3+/-6.8 mg/dl (p<0.001), low-density lipoprotein cholesterol 109.8+/-35.4 mg/dl v 93.6+/-33.9 mg/dl (p<0.001), and triglyceride 190.7+/-95.4 mg/dl v. 157.6+/-73.5 mg/dl (p<0.001), respectively. In subgroup analysis by age, the younger coronary artery disease group (< or = 40 years) had significantly higher total and low-density lipoprotein cholesterol levels than the older group (> 40 years), viz. 194.6+/-51.4 mg/dl v. 176.3+/-40.2 mg/dl (p<0.001), and 118.3+/-39.6 mg/dl v. 108.7+/-36.1 mg/dl (p=0.001). Triglyceride levels were not significantly different [211.7+/-105.1 mg/dl v. 187.8+/-93.6 mg/dl (p=ns)], being equally high in both subgroups and, although high-density lipoprotein cholesterol levels were different, this difference was minimal, being equally low in both [32.7+/-9.5 mg/dl v. 30.3+/-9.0 mg/dl (p=ns)]. In the subgroup analysis of those with coronary artery disease, diabetics had significantly lower total cholesterol [174+/-41.1 mg/dl v. 180.4+/-42.4 mg/dl (p<0.001)] and low-density lipoprotein cholesterol levels [105.8+/-34 mg/dl v. 111.5+/-35.8 mg/dl (p<0.001)] than non-diabetics, whereas triglyceride and high-density lipoprotein cholesterol levels were not significantly different, triglycerides being equally high in both [186.2+/-95.5 mg/dl v. 192.5+/-95.2 mg/dl (p=ns)], and high-density lipoprotein equally low in both [30.9+/-9.3 mg/dl v. 30.5+/-9 mg/dl (p=ns)]. The commonest associated conventional risk factor in diabetics was hypertension and, in the younger age group (< or = 40 years), it was smoking and a positive family history of premature coronary artery disease.

Conclusions: We conclude that in north Indians, coronary artery disease occurs at much lower levels of total cholesterol and low-density lipoprotein cholesterol than other populations, and high triglyceride and low high-density lipoprotein levels are more of a universal phenomenon in this population. Younger patients have a more atherogenic lipid profile than the older subgroup with coronary artery disease, and smoking and a family history of premature coronary artery disease are the most common associated risk factors. Total cholesterol levels seem to play a lesser role in the occurrence of coronary artery disease in diabetics, the presence of which is in itself overwhelming for the occurrence of coronary artery disease.