Sunday, September 25, 2011

Coffee, Caffeine and Blood Pressure

Does coffee or caffeine increase blood pressure? Patients often wonder if their blood pressure measured in the office is higher because of the coffee they drank just before the visit. Could that be true? Should you cut down on coffee or caffeine if your blood pressure is up?

A detailed review of the effect of caffeine on blood pressure was just published. Although coffee contains many chemical substances, caffeine is the component with the main effect on blood pressure. So decaf coffee was not addressed in this paper.

Most of the studies in this publication used 200-300 milligrams of caffeine in their tests. This amount of caffeine is roughly equivalent to 1 and ½ to 2 cups of coffee.

So what did this review of coffee, caffeine and blood pressure show?

If you are not regularly drinking coffee every day, then blood pressure can definitely increase starting at 1 hour after drinking and lasting 3 hours or more.
And the increase in blood pressure is not trivial.

8 mm in the systolic (upper number) and 6 in the diastolic (lower number) have been seen on average. So this is a significant increase in blood pressure that happens when caffeine is given to those who were not using caffeine for 1-2 days or more. And the increase in blood pressure with caffeine was seen in both those taking and not taking medication for high blood pressure.

But what happens if you drink coffee every day? Does regular caffeine or regular coffee drinking increase blood pressure and turn someone who has normal blood pressure into someone with high blood pressure?

The best evidence indicates that it probably does not. Maybe the other chemical components of coffee help or maybe you just adapt to the effects of the caffeine.

And other questions still remain.
For example is heavy consumption of coffee harmful in those with uncontrolled high blood pressure?

The good news is that there is no evidence that long term regular coffee use increases the risk of cardiovascular disease such as heart attacks.

More studies are needed but it appears that if you enjoy your coffee, you should do so every day. And if you drink it every day, the coffee is not likely causing increased blood pressure.

And keep in mind, you can always consider lowering your caffeine intake.
How about green tea or decaf coffee?

And when blood pressure control is in doubt, testing your blood pressure at home or, even better, 24 hour ambulatory blood pressure monitoring can be very informative. 
More about blood pressure monitoring in an upcoming post.

Your Diabetes Endocrine Nutrition Group 

Sunday, September 18, 2011

Stop the Metformin?

For many reasons, metformin is often the first drug prescribed for Type 2 Diabetes.
But if your kidney function is reduced, the doctor usually tells you to stop the metformin.
And, if you stop the metformin your blood sugars will usually go up a lot. You will then need something else for blood glucose control. Often insulin will be needed.

Metformin does not hurt the kidneys. But it is removed from the body via the kidneys. Since metformin came to market in the U.S. in 1995, there has been concern that if the levels of metformin build up in the blood you might get a serious condition called lactic acidosis. A related drug for diabetes called phenformin was removed from the market because it really did cause lactic acidosis.

It is now clear that the concern about metformin causing lactic acidosis is way overblown. A recent article in Diabetes Care reviews this topic.

It is not clear if metformin even increases the risk of lactic acidosis. If metformin does increase the risk of lactic acidosis, that risk appears to be very low. There were about 3-4 cases of lactic acidosis in 100,000 metformin users over 1 year. That rate is similar to the rate occurring in persons not on metformin.

And those few cases in metformin users occurred when there were other causes of lactic acidosis present. Lactic acidosis generally happens in very sick people in the intensive care unit with severely low blood oxygen (hypoxemia) and or severely low blood pressure (hypotension).

The authors of this recent article argue for continuing metformin in patients with Type 2 Diabetes and chronic kidney disease with an eGFR as low as 30 . This approach to prescribing metformin is used in the United Kingdom, Canada and Australia. Many endocrinologists and diabetes experts in the U.S., including our group, will continue metformin in most patients with an eGFR as low as 30.

Too often, metformin is stopped when patients are doing fine on it.
I hope more patients will benefit with wider implementation of these recommendations in the U.S..

Saturday, September 17, 2011

Diabetes Drug Allergies

Diabetes drugs, like many medications, can cause a variety of unwanted effects but diabetes drug allergies are quite rare. If you are allergic to a drug, your immune system is turned on in a harmful way. Skin rash is the most common sign when you take a drug to which you are allergic.

Drug side effects are different from drug allergies. For example, diarrhea is a common side effect of metformin but having this side effect does not mean you are allergic to metformin.

If you are allergic to a drug, it is often dangerous to give you that drug. That’s not the case with what we call side effects. We can often deal safely with side effects.

If you had the side effect of diarrhea from metformin that went away when you stopped it, you could still safely take metformin again. By taking a slow release form of metformin, or a lower dose, or by  taking metformin with food you might be able to prevent the side effect of diarrhea. Allergy to metformin is extremely rare, if it  occurs at all.

Allergies to some drugs, like penicillin and sulfa antibiotics are fairly common. If you are truly allergic to those antibiotics, you should not take them.

One question that comes up in our practice is if you are allergic to sulfa antibiotics can you safely take a sulfonylurea diabetes drug? Sulfonylureas  include glimepiride, glipizide, glyburide and others. Sulfonylureas are cheap and are still used often for diabetes. But sulfonylureas have their drawbacks.

Although sulfa antibiotics have some chemical similarity to sulfonylureas, virtually all people who are allergic to sulfa antibiotics have no problems with sulfonylureas.

Allergies to sulfonylureas are quite rare. In over 27 years of practice in diabetes and endocrinology, I believe I have seen maybe one person allergic to an sulfonylurea.

So all those with sulfa allergies, if you recently were given a prescription for a sulfonylurea don't worry about being allergic to it. There are better and more important things to worry about. 
I’ll discuss some of those in an upcoming post on the sulfonylureas.

Sunday, September 11, 2011

B12 Pills Instead of Shots and Metformin

People who are unable to absorb vitamin B12 in their diet can usually do fine with B12 pills instead of shots. I am amazed to see so many still getting the inconvenient costly intramuscular injections of vitamin B12 when they would do fine with B12 pills instead of shots. 
And vitamin B12 pills are available over the counter without a prescription.

A dose of 250 micrograms of vitamin B12 a day should be fine in most people. Those diagnosed with pernicious anemia or gastrointestinal problems may need 1000 micrograms daily. These findings on the use of B12 pills instead of shots are not new.

What is relatively new is the finding that people taking metformin for Type 2 Diabetes are about 5 times more likely to get vitamin B12 deficiency. 11 percent more of the metformin users in a recent randomized controlled trial had low vitamin B12 levels compared to the non-users of metformin. It is likely that metformin reduces absorption of vitamin B12 from the intestine.

I recommend a yearly blood test measurement of vitamin B12 levels in my patients on metformin. Methylmalonic acid (MMA) increases in the blood when there is vitamin B12 deficiency so an elevated level of MMA confirms vitamin B12 deficiency. But other conditions such as reduced kidney function can increase the MMA. And a low or borderline vitamin B12 level even without an elevated MMA may still be appropriate to supplement with vitamin B12.

Absorption of vitamin B12 is very complicated. Animal products, mostly meat and fish, are dietary sources of vitamin B12. Vitamin fortified breakfast cereals and multivitamin supplements also contain vitamin B12. 

6 micrograms is the Recommended Daily Intake (RDI) of vitamin B12.
So most of those vitamin B12 pills contain a lot more than the RDI. The high doses allow for most people needing a supplement to get adequate levels with B12 pills instead of shots.

Many people as they get older have problems absorbing vitamin B12 even if they don't take metformin. And a multivitamin supplement may not be adequate.

Vitamin B12 is important for brain and nerve function and blood cell formation.
It seems reasonable to supplement vitamin B12 when the level is low even before symptoms occur. There is no evidence of problems by doing so. And symptoms from low B12 can be confused with other conditions, like diabetic neuropathy.

A high level of vitamin B12 does not appear to be harmful. But it’s appropriate to monitor vitamin B12 levels in people taking supplements.

By the way, there is no benefit shown from sublingual vitamin B12 over vitamin B12 pills.

Vitamin B12 pills instead of shots can be used by most people and metformin users should have B12 levels checked. Are you on a vitamin B12 supplement?

Monday, September 5, 2011

Calcium Heart Controversy

A recent publication created a calcium heart controversy. Many people have little calcium in their diet and so they take a calcium supplement to help their bones.  An analysis published in the British Medical Journal suggested an increased risk of cardiovascular events, mostly heart attacks, with calcium supplements.

A huge controversy followed. Many experts have challenged the conclusion of heart risk from calcium supplements.
Have you heard about this? Has your doctor told you to reduce your calcium intake?

Now the American Society for Bone and Mineral Research has published a thoughtful response to that BMJ paper.

Many questions remain and the calcium heart controversy has not ended.
My take on this is to review each person’s dietary intake of calcium. When that intake is not adequate I recommend a calcium supplement aiming for about 800-1000 milligrams of total calcium per day. The amount I recommend depends on the individual.

Dietary calcium mostly comes from milk, cheese, yogurt, or calcium fortified juices or sardines. Other foods like broccoli are not good sources of calcium. They do not get absorbed well.

And the diet is the best way to get your calcium. But if you don't enjoy those high calcium foods or don’t eat them often, you ought to take a calcium supplement.

The lowest cost calcium supplements are in the form of calcium carbonate. There are many available calcium carbonate supplements. Most provide at least 500- 600 milligrams of elemental calcium per pill. Some people choose chewable preparations like Tums or Viactiv.
In some cases, I recommend other forms of calcium but for most people calcium carbonate works best. And you’ll need less pills or chews with calcium carbonate than the other forms of calcium.

I try to ensure that all my patients are getting enough vitamin D. Vitamin D is not just important for your bones. Once I get each person’s vitamin D level up to goal, I advise them to take 2000 units of vitamin D each day to maintain a  level of about 40 ng/ml. . Vitamin D is easily available as a supplement without a prescription.

I recommend taking the vitamin D supplement year round. Yes, even in the summer. Almost everyone I see drops down to too low a level if they stop the vitamin D supplement. Most people don't get that much sun exposure, especially in northern latitudes like Cleveland Ohio.

The calcium heart controversy has not been resolved. But the overwhelming evidence does not show a heart risk from calcium supplements. And vitamin D remains important. I encourage each of you to discuss this with you doctor. 

Saturday, September 3, 2011

Clinical Trials?

Have you been asked to participate in clinical trials? 
Has a clinical trial been offered for you to consider?

Chances are the answer is no! That’s because very few physicians offer this option to their patients. It is difficult to get numbers on this but in my estimate probably less than 1 in 100 doctors have served as principal investigators in clinical trials.

And there are only 12 Certified Physician Investigators in the State of Ohio.
I am one of those.

You might say so what about clinical trials? I don't want to be a guinea pig to test out a drug before it gets approved! Well just think for a moment. What if everyone felt that way about clinical trials? We would not have any drugs or medical devices for treatment. Drugs that you are taking right now would not be available if no one participated in clinical trials. And all drugs have been tested in animals, sometimes guinea pigs, before they are tested in humans.

Before any new drug or medical device comes on the market, it must be extensively tested and then approved in the U.S. by the Food and Drug Administration (FDA). In Europe, the European Medicine Agency (EMA) has authority.

So why might you consider taking part in a clinical study? Maybe because you want to simply help advance medical knowledge and help others suffering with your condition.

Maybe you are suffering with a disease for which there is no truly effective treatment. Or maybe you’ve tried all approved treatments without much success.

Most trials will give money to cover the cost of your time and transportation. And the treatment being tested is offered at no charge to you. Sometimes you receive other medication or supplies at no cost. And no health insurance is required to participate in clinical trials. But most people do not participate in clinical trials for financial reasons.

I have found that many people choose to participate in clinical trials because they value the extra special and detailed attention they get when they are in a clinical trial as compared to usual care. We follow participants really closely in most clinical trials.

Of course, clinical trials are not the same as regular medical treatment. They are experiments, designed to test new medicines, devices, or other therapies. And in most clinical trials, there is no guarantee that you’ll actually receive the experimental treatment being tested.

There are very strict rules for conducting clinical trials. Each clinical trial has a protocol that the clinical research team has to follow. Many people are unable to participate simply because they may not qualify based upon the clinical trial protocol.

Our site has been involved in many important clinical trials sponsored by the National Institutes of Health and by pharmaceutical companies. We have a dedicated research team with nurses who are certified in clinical research. They have many years of experience in clinical trials.

The physician and principal investigator supervises the clinical trial. At our site, that’s me.

Our practice values the opportunity to offer clinical trials to a select few of our patients.

We hope that each clinical trial will yield important results.

We hope to reduce the burden of human suffering from disease.
These are some thoughts to keep in mind if you are ever offered to participate in a clinical trial.
Feel free to contact our clinical research department  if you want to know what studies we are currently conducting.