www.diabeticretinopathy.org.uk

General

Cholesterol & lipids

David Kinshuck

 

Types of blood fat/lipid

'Lipid' is the medical word for 'fat in the blood'. Too much fat in the blood is harmful. With or without diabetes, high fat levels will make many diseases more likely, such as age related macular degeneration and heart disease. But in addition, in diabetes, high blood fat levels increase complications greatly.

Generally we do need a little fat in our diet. Lipids make up the outer membranes of cells in the body, so it is essential we have do have some healthy fats in our diet.

There are two main types of fat in the blood, triglycerides and cholesterol. There are two types of cholesterol, high density lipoprotein (HDL), and low density (LDL). Triglycerides and LDL cholesterol are harmful. Many laboratories measure the 'total' cholesterol, and generally this is equivalent to the LDL level, and the lower the better.

 

Cholesterol

Triglceride

Low cholesterol and triglyceride levels reduce diabetic complications. Average levels in the UK are 5.2 mmol/l, and these are too high. Most authorities would like lower levels...the lower the better as long as you feel well. A healthy level is <3.5mmol/l. NICE target <4.0 mmol/l. see HPS

 

Causes of a high cholesterol

A high cholesterol may be caused by such problems as

 

A healthy diet

This is most important, summarised here, in detail here.

 

statins reduce heart problems 25%, graph

The benefit from statin treatment protecting the heart. Retinopathy patients will probably benefit in a similar way... progression will be halved enlarge

Statins

The main drugs to lower cholesterol are statins. Statins work on the liver so it makes less cholesterol. The target total cholesterol is <4.0 mmol/l. NICE  recommend statins where tolerated for all patients >40y, and at risk patients at a younger age. Statins reduce total morbidity and mortality.

The most common side effects of the statins are abdominal pain, flatulence, diarrhoea, nausea, vomiting, headache, myalgias, rash, angioedema (allergic swelling of parts of the body). Some give insomnia, pins and needles, numbness of the fingers and toes, and other problems.

 

Common regimes

  1. atorvastatin Lipitor start 20mg/day 80mg common dose
  2. simvastatin  Zocor First choice NICE. Zocor 40mg common dose increasing to 80mg if not reaching target.
  3. rosuvastatin Crestor for a greater drop in cholesterol start 10mg/day 5mg Asian patients

Side effects mean than about one person in 5 has to stop (my estimate). 1.5% of patients treated with statins are found to have elevated liver enzymes (chemicals), with more problems occasionally. Liver enzyme levels may rise (and the rare case of hepatitis) but get better after the statin is stopped. Liver function blood tests should be tested before starting treatment and repeated now and again. Sometimes other medications may lead to liver and muscle problems if given together with a statin.

Statins are now recommended for most adults with diabetes, and should be used if there are no side effects. If one statin causes side effects, that drug should be stopped. Generally one of the others should be tried, and often the alternative will have no side effects. If all of the statins cause side effects, naturally none can be used. Some people have a specific genetic pattern that makes them susceptible to muscle problems. Statin  myopathy (BMJ 2008). 

 

Warnings ..statins

  1. Simvastatin...you MUST avoid grapefruit juice see
  2. Simvastatin...avoid certain anti-fungal/HIV treatment.
  3. Any person using a statin should report muscle pain, weakness, or cramps. Muscle enzymes will need to be tested with a blood test and you may need to stop treatment if they are above a certain level.
  4. Avoid excess alcohol
  5. rosuvastatin (Crestor) 5-10mg/day... must be started at this dose, no higher
  6.  nhlbi/guidelines/l/statins.pdf
  7. if myalgia develops, see BMJ 2012

Patients who are taking statins should avoid or minimise alcohol, and should not use a statin if the liver is very abnormal.

Anyone using statins who thinks they have side effects from then should ask their doctor or nurse. Concerning milder side effects, one option is to stop the statin and see if you feel better after 1-2 weeks. Then restart them and see if you feel bad again. This helps to confirm the statin is causing the side effect. You should discuss the situation with your doctor if you get side effects.

Many people using statins notice dry sore eyes. This may be a coincidence, and is not harmful. If your eyes are dry, ask for lubricants.

Rosuvastatin (Crestor) is is more powerful than others. It must be started at the lowest 5mg dose in certain patients (Asians, reduced kidney function, thyroids problems, muscle disorders..personal/in family, alcohol abuse, >70y, fibrate use). When used at this dose it occasionally causes problems, more often that the manufacturer states. However, if used with care local opinion advises it is safe to be prescribed in general practice....it is useful when the cholesterol drop with the other drugs (at their lower dose) is insufficient, and you need the cholesterol lower still.

It causes similar problems to the other statins as described on this page. At higher dose it is more likely to cause rhabdomyolysis (a serious muscle problem which can begin quickly). Myopathy BMJ  

Statins do increase the risk of diabetes 9%, (20%) and the risk of cataract, but the benefits usually exceed this risk. 

 

Ezetrol

Ezetrol together with a statin lowers the cholesterol further. There are normally no side effects. Adding to a statin lowers the cholesterol 25% extra. Ezetrol works by reducing cholesterol absorption from the gut, whereas statins reduce the production of cholesterol by the liver. Details here at netdoctor .

 

Fibrates

Triglycerides levels drop if you

But fibrates lower triglycerides

Fibrates are recommeded for nearly everyone with retinopathy, with benefit shown in the FIELD study. (If GFR >15 & no pancreatititis.) See Eye 2011 and the FIELD study. But such studies suggest they will be just as useful for patients with a normal triglyeride, and should probably be used in most patients (except younger patients): fenofibrate 200 mg/day. Nice recommend fibrates if triglyceride >4.5mmol/l, but we believe thisis outdated advice...they benefit nealy everyone with retinopathy. The FIELD study  identifies a 30%-40% reduction in retinopathy development when given early before complications. This is a very important study, and clearly many patients with highish triglycerides should be prescribed a fibrate such as Supralip. It may be that fenofibrate should be used in every person with exudative maculopathy. Some local experts suggest that fenofibrate 200 mg/day should be recommended to all adult patients unless there are contra-indications: