Low serum LDL cholesterol in patients with type 2 diabetes

Abstract

Background

Patients with type 2 diabetes (T2DM) typically exhibit a pattern of dyslipidemia with high triglycerides, low HDL cholesterol, and small LDL particles. We aimed at investigating whether also LDL cholesterol levels are altered in diabetic patients.

Methods

Lipid panels were obtained in a consecutive series of angiographied coronary patients (n = 750), and in a large sample of hypertensive outpatients (n = 5949).

Results

T2DM patients in the cohort of coronary patients (n = 164; 21.9%) had significantly higher triglycerides (203 ± 138 vs. 153 ± 91 mg/dl; p < 0.001), lower HDL cholesterol (44 ± 14 vs. 50 ± 14 mg/dl; p < 0.001), lower apolipoprotein A1 (140 ± 28 vs. 148 ± 28 mg/dl; p = 0.002), lower total cholesterol (211 ± 48 vs. 220 ± 42 mg/dl; p = 0.006) and, importantly, lower LDL cholesterol (122 ± 38 vs. 134 ± 35 mg/dl; p < 0.001) than non-diabetic subjects. Whereas apolipoprotein B was similar in T2DM patients as in non-diabetic subjects (113 ± 26 vs. 114 ± 25 mg/dl; p = 0.648), the LDL cholesterol/apolipoprotein B ratio was significantly lower (1.08 ± 0.24 vs. 1.18 ± 0.21; p < 0.001) and LDL particles were significantly smaller (257 ± 7 vs. 259 ± 6 Å; p < 0.001) in T2DM patients. Also among the hypertensive subjects, diabetic patients (n = 1632; 27.3%) besides higher triglycerides (173 ± 70 vs. 151 ± 65 mg/dl; p < 0.001) and lower HDL cholesterol (53 ± 17 vs. 57 ± 19 mg/dl; p < 0.001) exhibited lower total cholesterol (216 ± 44 vs. 222 ± 41 mg/dl; p < 0.001) and lower LDL cholesterol (127 ± 40 vs. 136 ± 37 mg/dl; p < 0.001) than non-diabetic subjects.

Conclusions

Both among angiographied coronary patients and hypertensive outpatients, LDL cholesterol is significantly lower in T2DM patients than in non-diabetic individuals.

Introduction

Patients with type 2 diabetes (T2DM) are at a two- to threefold increased risk of cardiovascular disease [1], and cardiovascular disease is the primary cause of death in these patients [2]. The identification and treatment of cardiovascular risk factors among diabetic patients therefore are of paramount importance.

Clinically, T2DM is defined through an elevation of glucose levels [3]. However, also alterations in the lipid profile are characteristic for patients with T2DM: Typically, these patients have high triglycerides, low HDL cholesterol (HDL-C), and a small LDL particle diameter [4]. This pattern of lipid abnormalities strongly increases the risk of vascular events in diabetic patients [5] and is referred to as the atherogenic lipid triad.

Also LDL cholesterol (LDL-C) is an important risk factor in patients with T2DM [6]. Statin treatment (which primarily decreases LDL) significantly reduces vascular events by about 20% in diabetic patients, in particular in the very high-risk subgroup of diabetic patients with coronary artery disease [7]. Still, the majority of vascular events are not prevented through statin treatment in patients with T2DM. Whatsoever, LDL-C is the primary target for lipid intervention in current guidelines [8].

Given the central role of LDL in current lipid management, this atherogenic lipoprotein fraction in diabetic patients deserves particular attention. However, no previous investigation has focused on whether LDL-C levels in diabetic patients from current clinical practice differ from those of non-diabetic subjects. In the present study we therefore aimed at investigating the association of diabetes with serum LDL-C in two different large patient cohorts.