Blood pressure and diabetes Dec 2009
This page is best viewed printed out. It is a little complex...but if you are a patient you can take this to your practice nurse so it can be used for ideas. General advice is here, this page is here http://medweb.bham.ac.uk/easdec/prevention/Diabetes and Blood Pressure.htm
- Why do you need a blood pressure of 130/80?
- Take control of your blood pressure
- the renal physician 'screening' and preventing GFR drop (separate page)
- 'Home monitored' blood pressures
- White coat hypertension: fluctuating blood pressure
- Who do you need 115 or less systolic if you have proteinuria?
- Non-steroidal anti-inflammatroy drugs and blood pressure
- How can you lower your blood pressure?
- How often does your blood pressure need checking?
- General advice & the blood pressure control cycle
- Which drug
- A treatment plan
- Side effects
- ACEI inhibitors,
- ARB (angiotensin receptor blockers),
- calcium channel blocker,
- Studies, NEJM 2009, about hypertension with sound
- professionals/more details
- NICE Guidelines for patients 2011 for professionals page 267 (but these are not specifically for people with diabetes)
Complications from diabetes develop much more quickly if blood pressure is
high. This is illustrated in the graph opposite, from the UKPDS £23
Lifestyle has a major impact on blood pressure, but usually medication is needed in addition.
Each 1 mmHg of blood pressure rise causes a 1.2% increase in the number of problems.
In practice for instance, if you have diabetic maculopathy, a serious form of retinopathy, you need a very low blood pressure to stop (or slow down) your sight getting worse.
Unfortunately some people become ill if their blood pressure is too low, so like everything else in diabetes, the blood pressure you can achieve with tablets is a balance. The balance is between keeping well and avoiding diabetic problems, versus the side effects of the tablets, too low a blood pressure and becoming dizzy, and too many trips to the doctor.
Worldwide, blood pressure is undertreated. Australia
2008 . Long term control is needed (NEJM
2008). Candesartan Lancet. In
the DIRECT study
Candersartan reduced retinopathy progression by 18-34% (BMJ
10). White coat hypertension does contribute to retinopathy and does
need treatment 2008.
Some ethnic groups such as Afro-Carribeans seem to retain more salt, and
this causes much higher blood pressures see.
Each 1mm of blood pressure increases risk 5% (NEJM 2009). Treatment is important even in the very elderly BMJ12 BMJ12. <120 is harmful 2012. BP 130 (2012). General 2012.
If you have high blood pressure, take control. Buy a machine (in Birmingham, Lloyds Chemists sell good machines for ~£15). If your blood pressure is high and you are trying to lower it, check the pressure daily, and keep it below 140. Doctors need to test, and electronic systems can be helpful. 140 is the figure we advise patients middle-age and older who are using multiple medications, as lower levels are harder to achieve (lower levels are safer...the lower the better as elswhere on this page). Doctors and patients need to achieve lower blood pressures 2011 Nurses can help 2011. A healthy diet lowers BP. Depression & anxiety increase BP.
Aim for 130/80 (clinic BP) if well, perhaps slightly higher if you have lots of medical problems. About 5-10 mmHg lower for home blood pressures. Testing at home can be helpful JHH 2012.
Blood pressure upper targets
...the lower the better
|115/.....||105/...||to prevent deterioration in renal function (ideal)|
All the blood pressure measurements in this website relate to 'clinic' or 'hospital' blood pressures.
Home monitoring blood pressures should be 10mmHg (systolic) and 5mmHg (diastolic) lower see than these 'clinic' pressures.
Targets are only achieved in 20%. Observations suggest the target blood pressure of 130/80 is only achieved in 20%. Blood pressure rises significantly in type 1 diabetes as kidney disease (nephropathy) develops (EASDec 2002). 2010 recommendations.
There is a considerable risk of stroke in this condition. Many people say their blood pressure is normal at home or at their doctor's, but high in the eye clinic. Such fluctuating blood pressures are still harmful, indeed twice as harmful as regular hypertension. Lancet 2010 Masked blood pressure.
If you can achieve low levels, then your kidney function may not get worse. If you cannot achieve these levels, and you have protein in your urine, your kidney function may slowly get worse. Even lower blood pressures help further, see here.
NSAI (non-steroidal anti-inflammatory) drugs, such as ibuprofen (eg Nurofen), are not recommended for long term use. They increase blood pressure.
No one is telling you what to do, and your lifestyle is largely under your control (unless you are disabled). But a healthy lifestyle is essential if you want to keep your sight and your kidneys. Your doctor can arrange for help for you to stop smoking, and help if you are alcoholic.
Professionals are there to help when they can, but if you have no arthritis yet decide not to walk for 30 minutes a day, inevitably your health will suffer. 2 hours a day is the ideal time spent exercising if you are overweight, 1 hour if not. You may need 4 different tablets to lower blood pressure, as below. Lifestyle factors.
|such as walking or swimming, 30 minutes a day|
|salt||not adding much to food, and reducing amounts of processed food with salt already added|
|smoking||20/day triples the likelihood of problems from diabetes|
|losing weight||exercise more and eat less. Losing 10% weight will cause a marked reduction in blood pressure|
|contributes to high blood pressure: stick to less than 2 units/day. Each unit = 2.2 mmHg blood pressure.|
|a healthy diet|
|some drugs put blood pressure up||non-steroidals put blood pressure up (see box 4) e.g ibuprofen|
keep a record of your blood pressure
Keep a record. Why not carry the details with you for all your nurses and doctors to see?
The most accurate pressure is that measured by your practice nurse. Results
are higher when taken by doctors!
Generally it is not considered necessary to test your pressure at home with your own machine, but it can be very helpful.
Do not worry if you cannot reach the ideal blood pressure of 130/80 or below. Some people, particularly if you have lots of medical problems, may not be able to reach such a blood pressure. Discuss this with your doctor or nurse.
Each 10 mmHg rise in blood pressure causes and extra ~12% deterioration in retinopathy & kidney damge.
If you have high blood pressure and you are working with your doctor and nurse
trying to lower it, a test every 2-6 weeks is helpful. Naturally tests should
be more frequent if it is very high, or you need it very low because of your
Similarly, if you are well and your pressure is low (especially children), every 3-6 months is fine. Keeping your pressure low slows down the development of other problems that you may get with diabetes such as eye, feet, kidney, nerve, and heart problems.
So the lower your blood pressure the better, and this will delay needing laser for retinopathy, or, if you are already having laser, the laser is more likely to be effective.
Some people with high blood pressure can achieve a lower blood pressure by reducing salt intake. The difference occurs because people have different metabolisms, and these may be genetically determined by the genes you have inherited from your parents. (Salt sensitivity, review). 33% salt reduction from the current average level would reduce blood pressure 4mmHg (NEJM 2009..but this is an average, it will be much more in some people).
Sources of salt in our diet
|15%||natural in fresh food|
|15%||what we add at the table|
|70%||from convenience and processed food, most of which have salt added|
Amount in processed food
|1%||in cereals, such as corn flakes|
|>2%||vegetarian canneloni (tesco's);
Special K cereal
If you eat food with a lot of salt it tastes awful without....... for about 4 weeks, after which you should get used to the new taste. Then the food you used to like will taste salty!
This is not like cigarettes, which can be very difficult to stop.
Some African-Caribbean diets are very salt rich: herbs and spices make food tastier but have no blood pressure effect.
Losalt is a substitute, but is still 30% regular salt (sodium chloride). It is not recommended if your kidneys are damaged. Sea salt is still sodium chloride and just as harmful if you have too much.
A healthy lifestyle delays the development of high blood pressure. However, even with the healthiest lifestyle, and perhaps partly because of genes you have inherited from your parents, most people with diabetes develop high blood pressure eventually. At this stage drugs are needed to lower the pressure to prevent complications (as above).
If you start a new drug, and it makes you feel very ill, stop it right away and see your doctor. If you notice an effect that is not so serious, read the drug information leaflet with the drug. Some side effects are specific to the drugs, and some of these are mentioned below. Some are more general, such as dizziness when you stand up.
Compliance improves if the drug treatment is explained. Compliance is normally about 50%. Simply prescribing the medication is not sufficient. Patients need to know a little about the drugs, how they work, and why they are needed.
A stepped approach is helpful as below. Patient educational status, belief in taking the drugs, and encouragement by the family were important. A training program for doctors helps!
- start with ACEI inhibitors or ARBs (Angiotensin Receptor Blockers). Avoid if pregnant.
- added next..calcium channel blocker (amlodipine)
- next.. thiazides
- if potassium <4.6, spironolactone
- if potassium >4.5, increase the dose of thiazide
- beta blockers
- other drugs such as monoxidine
- loop diuretics such as frusemide if renal function reduced
The ASCOT study
suggests that ACEI inhibitor and calcium channel blocker are an effective combination. See British
Heart Association Candesartan DIRECT
There are many tablets available for reducing blood pressure. The aim is to lower the pressure gradually over several weeks or even months. Don't be worried if your doctor changes your tablets several times.
Treatments usually starts with a low dose which are then increased. If this is not enough, another type of tablet may be added. Sometimes combination tablets, which contain two drugs, are used.
Your doctor may also change your tablets if they produce side effects. Five blood pressure medications may be needed.
|If ACEI not well tolerated, stop and replace ACEI with ARB||Avoid if pregnant.||here|
|add calcium channel blocker
such as amlodipine 5-10mg OD
then add Bendrofluazide 2.5mg
(or other thiazide).
|if potassium <4.6, spironolactone 25mg od (increasing to 50mg od).||'resistant hypertension' BMJ 2012||NICE 2011|
|if potassium >4.5, increase the dose of thiazide diuretic|
|add selective beta-blocker
such as atenolol 25-50mg OD
|not suitable for asthma patients||here|
|add alpha-blocker, such as doxazosin
|Replace bendrofluazide with frusemide.
Add other drugs such as monoxidine or methyldopa, possibly in combination. Loop diuretics such as frusemide if renal function reduced.
|methyldopa may cause depression|
The vast majority of people taking tablets for high blood pressure feel perfectly well and have no side effects from the tablets. Their only problem is remembering to take the tablets! After starting new treatment it is only natural to think that any new symptoms must be caused by the treatment. If you do seem to have side effects, discuss them with your doctor who will be able to tell whether or not the tablets are to blame.
Most of the tablets for treating high blood pressure can also be used for other heart conditions. So don't be surprised or worried if you know someone with a different condition who is taking the same tablets as you.
Many people with diabetes have sore or watery eyes, and blood pressure tablets may make these worse. However, it is better to have sore/watery eyes than deteriorating sight, so the lower the blood pressure (as long as you feel well) the better. Naturally medication should be stopped if you are sure it is making you ill, and discuss problems with your doctor.
|Possible reaction with other tablets, including some that are available without a prescription, including herbal remedies. Check with your doctor or pharmacist before you take them.|
|Rash||May develop soon after you start a new treatment. Report this to your doctor. You may have developed an allergy to the tablets.|
|light-headed or dizzy||If you
feel, or if you faint. These effects may be particularly noticeable when
you get up from bending or lying down, or if you are older.
If these side effects are severe, it may be that your tablets have reduced your blood pressure too much.
Tell your doctor who might reduce the dose of the drug or give you different tablets.
ACEI inhibitors and ARBs cxcan cause high potassium levels.
ACEI stands for 'angiotensin
converting enzyme inhibitors'; they work by stopping the conversion of
an inactive substance in the blood called angiotensin 1 to the very potent
angiotensin 2, which produces spasm and constriction of the blood vessels.
Angiotensin receptor antagonists (ARB, also called angiotensin II inhibitors) are likely to be just as effective as ACEI inhibitors (ACEI).
Patients using ACEI and ARBs need monitoring with U & Es
(kidney function and electrolytes) tests. They work partly by making the
walls of the arteries relax and dilate. The first dose can cause quite a
large drop in blood pressure, so this dose is best taken last thing at night.
You should not take ACEI inhibitors if you are pregnant.
ACEI & ARB are generally recommended for diabetes, even if there is no hypertension (see). They reduce progression rate 50% in some studies. This may be because there are angiotensin receptors in the retinal cells.
Unwanted effects of ACEI/ARB
ACEI/ARB are generally better tolerated by patients than most of the other drugs. However, they can cause a marked fall in blood pressure, especially when first used by people who are also taking diuretics. They may also affect the function of the kidneys if this is already abnormal. When your doctor starts the treatment, they will take care to start you on a low dose and will regularly check your blood, as above.
Some ACEI may affect your sense of taste and cause skin rashes and, very occasionally, a major allergic reaction. Some people develop a persistent, dry, irritating cough. If this happens, you should tell your doctor about it.
ARBs are generally better tolerated, although some are more expensive. Also, whilst much research has identified the benefit of ACEI, there is less evidence about ARBs. However, concerning blood pressure and diabetes, they are generally felt to be as effective.
Types of calcium channel blockers
May cause ankle swelling. These are now usually added to patients already taking ACEI/ARBs
pass water more often when started
potassium (occasional blood test needed)
These are common drugs, now usually added when patients are taking
ACEI/ARB and calcium channel blocker. They were previously first line treatment
in non-diabetics. Very low doses (such as bendrofluazide 1.25mg) may be better,
but at present these are only available as combination drugs.
The doses opposite may increase blood fat levels, sugar levels, uric acid, and lower potassium levels.
These are often known as the 'water pills'. They work on the kidneys, helping them to pass more salt and water into the urine. This triggers hormone reactions which lower the blood pressure. If passing water too much makes your life difficult or leads to incontinence, tell your doctor.
There are three types of diuretics. These are: thiazide, loop diuretics, and potassium-sparing diuretics. If you take a thiazide or loop diuretic, your doctor will arrange a blood test a few weeks after you start, to check the potassium level in your blood. If this is getting low, you will be given potassium supplements, or a potassium-sparing diuretic will be added. If you are diabetic, you may find that diuretics raise your blood sugar levels.
Loop diuretics include frusemide or bumetamide, and are especially useful in diabetic nephropathy, often combined with an ACEI inhibitor.
If potassium <4.6, spironolactone 25mg od (increasing to 50mg od). This can give breast tenderness and gynaecomastia: if this happens substitutes are available. If more than 3 drugs are needed, this is classified as 'resistant hypertension' BMJ 2012, NICE 2011.
If potassium >4.5, increase the dose of thiazide diuretic
|unwanted / not recommended|
These are also first line agents in non-diabetics. Beta-blockers as a whole are less effective in Afro-Caribbeans. They work by stopping the action of adrenaline. This reduces the pulse rate and limits the amount the pulse rate rises when you exercise.
Serious side effects are rare if beta-blockers are used with care. Beta-blockers should not be stopped suddenly without medical advice. If you also have angina, stopping beta-blockers too quickly can make it worse. If you have diabetes, you need to be aware that beta-blockers may suppress the usual warning signs of low blood sugar - such as palpitations and tremor. If you stop taking beta-blockers, you may feel as if your heart is beating abnormally fast or heavily (palpitations). Ask your doctor for advice if this continues.
Vaso-dilating beta-blockers may be preferable see.
The effect of drug treatment may take 2 months to be apparent. But if there
is severe retinopathy with significant hypertension 1-2 week follow up may
be best, to check for side effects and that the blood pressure is dropping.
Once stabilised, BP can be checked every 3-6 months. Electrolytes should be checked prior to drug treatment. If diuretics are used then potassium should be checked after 4 weeks treatment. Special monitoring is required for ACEI inhibitors.