Table 5.
Suggested comments for reports on various lipid abnormalities.
| Category | Lipid Abnormality | Comment |
|---|---|---|
| Abnormalities involving HDL-C | ||
| A1 | Isolated increase in HDL-C >2.5 mmol/L | Increased HDL is considered protective for CVD, but must be considered in context of all other risk factors. Increased HDL can be seen in pregnancy, oestrogen treatment, high alcohol intake, following prolonged intensive physical exercise, during anticonvulsant therapy, as a consequence of exposure to microsomal enzyme inducers such as pesticides, and as an inherited condition. Increased HDL-C does not exclude risk from increased LDL-C. |
| A2 | Normal HDL-C (1.0 – 2.5 mmol/L) and TG 1.6 – 4.4 mmol/L | This pattern may be seen in non-fasting specimens, pregnancy, with oestrogen (HRT) or bile-acid sequesterant usage and in association with high alcohol intake. |
| A3 | Decreased HDL-C and TG 1.6–4.4 mmol/L | Decreased HDL with increased VLDL. This pattern may be seen in the metabolic syndrome, type 2 diabetes, obesity, renal impairment, hepatic impairment, intercurrent illness, drugs, and familial forms of hypertriglyceridaemia. Decreased HDL is a risk factor for CVD. Suggest assessment of overall risk for CVD with the proviso that small dense LDL may be present, in which case LDL-C may underestimate CVD risk. |
| A4 | Decreased HDL-C <1.0 mmol/L | Decreased HDL may accompany intercurrent illness. It is also seen in hypoalpha-lipoproteinaemia (various forms including Tangier disease) and in association with defects in the ABCA1 transporter protein. In most of these circumstances it is a risk factor for CVD. |
| Abnormalities of LDL-C | ||
| B1 (a) | LDL-C >2.0 mmol/L to 4.0 mmol/L (HDL-C and TG normal) | LDL exceeds target for high risk patients and may be excessive in some individuals |
| B1 (b) | LDL-C >4.0 mmol/L (HDL-C and TG normal) | Increased LDL can be seen in hypothyroidism and nephrotic syndrome. Primary causes include polygenic hypercholesterolaemia, Familial Hypercholesterolaemia, Familial Defective ApoB-100 and Familial Combined Hyperlipoproteinaemia. Increased LDL is a risk factor for CVD. Assess overall risk and consider treatment. LDL-C <2.0 mmol/L is the treatment target for very high risk patients (NHFA 2005). |
| B2 | LDL-C <1.0 mmol/L | Decreased LDL can be seen with lipid-lowering therapy, severe illness or in rare inherited conditions (e.g. abnormalities in Apolipoprotein B or lipoprotein assembly). |
| B3 | LDL-C >4.0 mmol/L and markedly abnormal LFTs | Lipoprotein X may be seen in patients with cholestatic liver disease and lecithin-cholesterol acyl transferase deficiency. In some cases an abnormal band, which is consistent with Lipoprotein X, is present on lipoprotein electrophoresis. Additional tests may confirm the presence of disk-like Lipoprotein X. |
| Abnormalities in TG | ||
| C1 | TG 1.6 – 4.4 mmol/L and TC usually< 5.0 mmol/L | Mild hypertriglyceridaemia due to increases in chylomicrons and/or VLDL. This pattern can be seen in non-fasting or post-prandial states. Ensure patient has fasted 9 to 12 hours prior to performing lipid studies. Also consider pregnancy, exposure to alcohol, estrogens, bile acid sequesterants, intercurrent illness, other drugs, obesity, metabolic syndrome, type 2 diabetes, renal impairment, hepatic impairment, and familial forms of hypertriglyceridaemia. Assess HDL-C, which may be reduced. |
| C2 | TG >4.4 mmol/L and TC <5.0 mmol/L | Chylomicrons increased. If patient has fasted 9 to 12 hours prior to performing lipid studies, increased chylomicrons may be due to a defect in lipoprotein lipase activity. This can be due to mutations in the gene for lipoprotein lipase or secondary to some autoimmune conditions. This condition poses a risk of pancreatitis. Plasma TG <10 mmol/L is recommended to minimise this risk. LDL-C and HDL-C are usually substantially reduced, but if chylomicronaemia is severe, TC may exceed 5 mmol/L. |
| C3 * | TG >4.4 mmol/L and TC >4.9 mmol/L (To determine which comment is appropriate in these categories additional tests may be necessary to determine the lipoprotein abnormality) | IDL (intermediate density lipoproteins) are also known as “remnant” lipoproteins because they are formed as the residual from the action of lipoprotein lipase on triglyceride-rich lipoproteins (VLDL and chylomicrons). Alternative names for this condition are remnant dyslipidaemia, broad – beta disease and Type 3 hyperlipidaemia. Increased IDL can be seen in individuals with obesity, diabetes mellitus, some autoimmune conditions and treatment with steroids, on a background of polymorphisms in the gene for Apolipoprotein E. |
| C4 | Increased VLDL ± increased LDL can be seen in diabetes mellitus, obesity, oestrogen treatment, excess alcohol intake, hypothyroidism, renal impairment, other drugs, metabolic syndrome, hepatic impairment, Familial Combined Hyperlipoproteinaemia and familial forms of hypertriglyceridaemia. This pattern is usually associated with decreased HDL. Decreased HDL and increased LDL are risk factors for CVD. Suggest assessment of overall risk for CVD and consider treatment where appropriate. Targets for high risk patients are TG <1.5 mmol/L and LDL-C< 2.0 mmol/L (NHFA 2005). | |
| C5# | Increased VLDL (LDL-C may vary) and increased chylomicrons can be seen in individuals with high dietary fat intake, obesity, estrogens, bile acid sequesterants, intercurrent illness, other drugs, metabolic syndrome, type 2 diabetes, renal impairment, hepatic impairment, high alcohol intake, or familial forms of hypertriglyceridaemia, There is a background of reduced lipoprotein lipase activity which may be hereditary or due to the saturation of enzyme activity by the excess VLDL and chylomicrons. This pattern is usually associated with decreased HDL. Decreased HDL-C is a risk factor for CVD. Suggest assessment of overall risk for CVD and consider treatment where appropriate. Targets for high risk patients are TG <1.5 mmol/L (which may be difficult to achieve under these circumstances) and HDL-C >1.0 mmol/L (NHFA 2005). This condition is associated with a risk of pancreatitis. Plasma TG <10 mmol/l is recommended to minimise this risk. | |
*
Moderate to severe hypertriglyceridaemia and hypercholesterolaemia may be seen in this category. Often the TC and TG concentrations may be similar.
#
Gross hypertriglyceridaemia and severe hypercholesterolaemia may be seen in this category resulting from reduced clearance of chylomicrons and VLDL. Typically, TG may be 3 − 4 x TC concentration.