Dyslipidaemia is a major contributor to the increased risk of heart disease found in people with diabetes. An increase of 1 mmol/L LDL-C is associated with a 1.57-fold increase in the risk of coronary heart disease (CHD) in people with type 2 diabetes. A diagnosis of diabetic dyslipidaemia requiring pharmacological treatment is determined by the person's lipid profile and level of cardiovascular risk.
Methods and outcomes
We conducted a systematic review and aimed to answer the following clinical question: What are the effects of interventions for dyslipidaemia in people with diabetes? We searched: Medline, Embase, The Cochrane Library, and other important databases up to June 2007 (BMJ Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
We found 21 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
In this systematic review we present information relating to the effectiveness and safety of the following interventions: anion exchange resins, combined treatments (for lipid modification), ezetimibe, fibrates, fish oil (for lipid modification), intensive multiple intervention treatment programmes (for lipid modification), nicotinic acid (for lipid modification), and statins.
Dyslipidaemia is characterised by decreased circulating levels of high-density lipoprotein cholesterol (HDL-C) and increased circulating levels of triglycerides and low-density lipoprotein cholesterol (LDL-C).
Dyslipidaemia is a major contributor to the increased risk of heart disease found in people with diabetes.An increase of 1 mmol/L LDL-C is associated with a 1.57-fold increase in the risk of CHD in people with type 2 diabetes.A diagnosis of diabetic dyslipidaemia requiring pharmacological treatment is determined by the person's lipid profile and level of cardiovascular risk. The classification of cardiovascular risk and lipid targets for drug treatment differ between the USA and the UK, and the rest of Europe. We used the United Kingdom Prospective Diabetes Study (UKPDS) risk calculator to estimate 10-year cardiovascular risk, and categorised a 15% or more risk as "higher risk", and 15% or less as "lower risk" according to the UK clinical guidelines. We found no RCTs of a solely lower-risk population, although some studies were excluded because of insufficient data to calculate risk. In clinical practice, most people with diabetes are increasingly considered at high cardiovascular risk, regardless of the presence or absence of other risk factors.
Statins are highly effective at improving cardiovascular outcomes in people with diabetes.
Statins reduce cardiovascular mortality in people with type 2 diabetes with and without known CVD, and regardless of baseline total and LDL-C concentrations.Different statins seem to have similar efficacy at reducing LDL-C.
Combining statins with other treatments (such as ezetimibe or a fibrate) seems to reduce LDL-C more than statin treatments alone.
Combinations could be useful in people with mixed dyslipidaemia where one drug fails to control all lipid parameters.
Fibrates seem to have a beneficial effect on cardiovascular mortality and morbidity by reducing triglyceride levels.
In people with mixed dyslipidaemia, statins may also be required.
Intensive-treatment programmes involving multiple interventions (people seen by a nurse every 4-6 weeks) seem better at reducing cholesterol than usual-care programmes.
Fish oils may reduce triglyceride levels, but also seem to increase LDL-C levels, making them of limited benefit to most diabetic patients.
Nicotinic acid seems effective at increasing HDL-C and may reduce triglycerides. However, in clinical practice, nicotinic acid alone is not the preferred treatment for hypertriglyceridaemia, but may be used in combination with a statin in people with mixed dyslipidaemia, or in those unable to tolerate fibrates.
Nicotinic acid seems to increase the incidence of flushing, particularly in female patients.
We don't know whether anion exchange resins or ezetimibe are useful in treating dyslipidaemia in people with diabetes, but they could be used in combination with a statin if the statin alone fails to achieve lipid targets.