Saturday, July 28, 2012

Blood glucose testing tutorial and key points

Blood glucose testing tutorial and key points

Blood glucose testing is very helpful if you have diabetes.
But many patients and doctors fail to understand how to make sense out of blood glucose testing.

Here I present a brief tutorial on blood glucose testing and share some key points with you.
I have worked in diabetes care since blood glucose meters became available in the early 1980s.

First, not everyone with diabetes needs to do blood glucose testing.
Some people can test just occasionally, maybe one to four times a week.
So who does fine testing just occasionally?
Those with Type 2 Diabetes who:
·      are not on a drug, like insulin or sulfonylurea, that could cause low blood sugars and
·      are under good control based upon previous glucose measurements and A1c and
·      are feeling okay

Frequent blood glucose testing for those with Type 2 Diabetes who are under good control and not on insulin or sulfonylurea is simply a painful waste of time and money. A recent analysis of studies confirmed that frequent blood glucose testing testing was not helpful for these persons.

But a study published in 2011 suggests that if you are not using insulin and are not under good control,  blood glucose testing can be helpful in getting under better control but only if your doctor knows what to do with the numbers.

Now, if you take insulin for control of your diabetes you should definitely be doing blood glucose testing.

For any of the following reasons:
·      to help achieve and maintain good glucose control to stay healthy and prevent the “complications” of diabetes
·      to detect hypoglycemia; that’s a too low glucose of below 70 mg/dl.
·      to find out if  your sugar is far too high or low when you are feeling unwell

        So  now you know who should test and why?
        But what should you be aiming for in terms of target glucose levels?

In general, in adults who are not pregnant, we aim for before meal sugars of 80-120 and perhaps a bit higher at bedtime, 90-140.

Some people need to do blood glucose testing about 2 hours after meals. 
The goal 2 hours after meals is 90-180 mg/dl. 
Ideally, we would like those after meal sugars between 90 and 140.

Keep in mind that these are general targets.  Your doctor should discuss your individual glucose goals with you.

Another way to tell whether you are at glucose goal is to measure your Hemoglobin A1c or A1c for short. This test gives an idea of your average sugar over the past 2-3 months.
We do an A1c  quickly in our office. It takes 3 minutes and needs a drop of blood from a finger stick. The A1c is not affected by eating.

To tell whether your glucose control is good we need to examine and review both your glucoses from your monitor and the A1c.

The A1c does not tell the whole picture. The A1c is like the forest and the glucoses are like the trees. And sometimes the A1c can be very misleading. More on that in a future post.

A few general points:  Be sure to use blood glucose strips that are not expired. Check the date. Some meters still give a reading if the strips are expired. But you’ll get screwy numbers with expired strips.

And some meters still need to have the code change when you use a new batch of strips. And keep strips in the airtight container they come in.

Be sure you do not have sugar on the skin of your fingers. Fingers contaminated with sugar on the skin will give a falsely high reading

I hope you know that you don't have to use your fingers all the time. Most meters allow for alternate site testing, for example on your forearm or palm of hand. Those areas hurt less. 

A visit with a certified diabetes educator (CDE) is  a must if you have diabetes. The CDE can help you with all these details and more about blood glucose testing.

So okay, you know the target blood sugars and you are aware of these general points,  how about specifics?

First remember that those who use insulin and who are not on a pump, do best if they are using a rapid-acting insulin before meals and a dose of long acting insulin daily. See my previous post on how to use insulin.

There are far less reasons to do blood glucose testing if you are taking NPH insulin (Humulin N or Novolin N) or premixed insulin like a 70/30 or 75/25 insulin. For several reasons, NPH and premixed insulins are simply inferior to the newer insulin analogs.

Although your meter records your blood sugars, it is very helpful to keep a written log or record of your blood glucose readings. Bring in your log to your doctor visits.
On the log it helps to include factors that affect your sugar including:
·      the insulin dose you took at that meal,
·      if you ate more or less than usual or the grams of carb in that meal
·      if you were physically active around that time
·      if you forgot to take your insulin
·      if you were sick or were on a medicine that might affect your sugars
·      if you felt strange at the time

That’s a lot to consider. A really neat, new, small meter, the iBGStar, works with the iPhone  and allows you to record all these factors.  The iBGStar app is free.

Most meter companies will provide software to allow you to download your blood glucoses and print those readings out. 

An app called Glooko allows you to manage a logbook for most meters on the iPhone but you need a cable to download your sugars from your meter to the iPhone.

You can and should review your logbook, probably every week or so. Once you understand what to look for, you can  detect patterns and trends so you can get your sugar under better control. The new One Touch Verio IQ meter can be helpful in showing trends or patterns.

Too often patients never examine their readings. They just wait until they see the doctor in 2 or 3 months?

And far too often even the doctor does not know how to make appropriate changes in insulin. Many just never learned.

But how to do you make appropriate changes in insulin?
Look for patterns and trends. And understand how insulin works.

The rapid acting insulins are Apidra, Humalog and Novolog. They all work for about 4 hours and start working in about 15 minutes. They have peak action, that's when they work the most, around 110-120 minutes after the meal. If you took enough rapid acting insulin before the meal then your blood glucose should be good before the next meal, about 4 hours later. If you did not take enough, you’ll be high. If you took too much, you’ll be low over the next 4 hours after that injection.

For example, Joe is taking 25 units of Lantus at dinner and takes 5 units of Apidra or Humalog or Novolog before dinner. These are his sugars before dinner and bedtime:

Before Breakfast                               Before Dinner            Bedtime
145                                                         128                                   212
137                                                         152                                   233
112                                                         117                                   199

He is not testing at lunchtime but you can see that his glucoses are not too bad at dinner or before breakfast. But they go up after dinner. That means his dose of rapid acting insulin is not enough for what he is eating at dinner. He needs more. You could not tell this unless he tests toward bedtime or about 4 hours after his mealtime insulin. 

The Lantus insulin takes 2-3 hours to work. Lantus works over 24 hours. Lantus has no significant impact on his sugar 4 hours later.

Joe’s blood glucose testing is an example of how you can use pattern recognition to improve glucose control.

Here’s another: Lucretia is taking rapid acting insulin before dinner and Lantus at bedtime. This is her blood glucose record:

Before Breakfast               Before Lunch         Before Dinner        Bedtime
122                                            199                         128                           145
117                                            176                         153                          158
99                                               203                        133                           127
108                                            189                         111                          139

Most of these sugars are not too bad. But you may see that Lucretia has a blood glucose rise from breakfast to lunch. In fact, her lunchtime sugars are her highest. She assures you that she does not eat or drink any caloric beverages between those two meals.

So how should Lucretia improve her sugars?  Well she might try eating a lower carb breakfast but she enjoys her 2 slices of toast each morning. Okay, so that means she needs rapid acting insulin -Apidra, Novolog or Humalog- before breakfast.

And now, one last example of pattern recognition in blood glucose testing: Dave is taking Humalog before each meal and Lantus after dinner.

Before Breakfast              Before Lunch           Before Dinner         Bedtime
183                                           89                             114                             136
199                                           123                          118                             119
172                                           63                             191                             127

The pattern you can see here is that Dave tends to have his sugar go up overnight. If he eats after his bedtime reading, that could be the reason. But he tells you no, that's not the case. So that means his glucose rise overnight is from his liver making too much glucose. 
See a previous post on this topic. He needs more Lantus to fix that.

Now how about that high reading, the 191, before dinner? That probably can be explained away by his low sugar before lunch that day. He got low because he mowed the lawn that morning and forgot to reduce his insulin dose for breakfast. The physical activity drove his sugar down. For several reasons, high sugars tend to occur after an episode of hypoglycemia. That happened to Dave; his low at lunch caused a high reading at dinner.

Two important last points about blood glucose testing:

Once you are under good control you will likely be able to test less frequently. This is often the case for those with Type 2 Diabetes whose sugars vary less than persons with Type 1 Diabetes. But many with Type 1 Diabetes do not have to test, day after day, 4 or more times a day. They may be able to stay under good control with less frequent testing.

Last point: Don't make up your glucose readings in your logbook or written record. You’d be surprised to learn how many people fabricate their readings!
We figure it out sooner or later and it wastes our time and energy. The meter does not lie and when we review your meter readings we’ll see that they don't match your logbook or record. 
Be honest. We won't yell at you. 

And now I hope you know more about blood glucose testing.

As endocrinologists, we strive to help improve glucose control and keep our patients well.
And we have better and better tools to help people, such as continuous glucose monitoring systems like the Dexcom Seven Plus

We can all thank the hard work and good minds of many scientists and entrepreneurs.
Be well.

Sunday, July 22, 2012

Does Super Beta Prostate work?

Does Super Beta Prostate work?
What is in Super Beta Prostate?
Is Super Beta Prostate one of those supplements like saw palmetto that has been proven in randomized controlled clinical trials not to help?
Or is it like raspberry ketones, a supplement promoted by a prominent physician on TV even though there is no scientific evidence for benefit in humans?

Well it turns out that Super Beta Prostate contains a substance from plants called beta-sitosterol. Beta-sitosterol has a chemical structure very similar to cholesterol.

Beta sitosterol (from Chemblink)

Cholesterol (from Chemblink)

Beta-sitosterol is found in our diet in small amounts.   Plants do not contain cholesterol but they do contain other sterols such as beta-sitosterol. Typically when sold as a dietary supplement, beta-sitosterol comes from soybeans.

Beta-sitosterol is one of many plant sterols that have been added to margarines like Smart Balance. When taken in sufficient amounts, at least 800 milligrams per day, such plant sterols can lower serum cholesterol up to 10%. Plant sterols work to lower cholesterol by making it more difficult for dietary cholesterol to get absorbed.
The effect of plant sterols on serum cholesterol has been known for over 50 years.

Okay, but how about Beta-sitosterol and the prostate?
Beta-sitosterol has been studied as treatment for symptoms from benign prostate enlargement. Most studies were fairly short but were randomized and placebo controlled. The two largest studies treated men for 6 months. One included 200 men; the other 177 men. 38 men continued treatment for up to 18 months

Overall a significant improvement in symptoms related to enlarged prostate were seen. There was reduced urinary frequency and improved flow and an expected decrease in the International Prostate Symptom Score, a standard measure of symptoms related to prostate enlargement.
Beta-sitosterol appears safe unless, of course, you have the disorder called sitosterolemia. Sitosterolemia also called phytosterolemia is probably not as rare as was previously thought but it sure is not common. One of my physician attendings during endocrinology fellowship has it.

So, if beta-sitosterol helps, how does it work?
It may work like finasteride (Proscar) but thus far studies are inconclusive.

The doses used appear to be around 60-130 milligrams a day.
And it is not clear if higher doses are more helpful for prostate symptoms.

Beta-sitosterol is the only active ingredient in Super Beta Prostate.
The rest of those ingredients do nothing for the prostate and you are better off without them.

If you decide to take beta-sitosterol, you can find a lot lower cost supplement than Super Beta Prostate. The product CholestOff contains beta-sitosterol. One pill a day of CholestOff is plenty if you are using for its prostate benefit.

 Keep in mind that you never know for sure exactly what you are getting in dietary supplements since they are not regulated like prescription drugs.

Be well. 

Sunday, July 15, 2012

Weight loss drug lorcaserin coming soon

Weight loss drug lorcaserin coming soon

The new weight loss drug, lorcaserin will be available in the ensuing months.
But just how safe and effective is lorcaserin?

And what is lorcaserin and how does it work?

The body chemical called serotonin serves many functions. Serotonin has an important role in appetite.  Serotonin like most body chemicals acts by sticking to a receptor on the surface of a cell.
After that binding to the receptor, a whole setting of changes or signals will occur. 

chemical structure of lorcaserin

Lorcaserin reduces appetite but does not increase metabolism or burning up of calories.

Previous drugs fenfluramine and dexfenfluramine also worked through serotonin and were quite effective with weight loss. Those drugs acted on different serotonin receptors, 5-HT2B , and in doing so, caused heart valve abnormalities in a significant percentage of people.

A small percentage of patients on fenfluramine and dexfenfluramine also developed increases in blood pressure in their lungs. This is called pulmonary hypertension.
Fenfluramine and dexfenfluramine were removed from the U.S. market in 1997 because of these adverse effects.

Lorcaserin binds to a different serotonin receptor, the 5-HT2c receptor.
Lorcaserin does not appear to have effects on heart valves or pulmonary artery pressure after 2 years of use.

Lorcaserin side effects include headache, dizziness and nausea. You would expect nausea in any drug that reduces appetite. 
Only about 7 % stopped participation in the studies because of side effects. No liver or kidney problems have been seen with lorcaserin. Quality of life reports were significantly better in those on lorcaserin.

But how effective is lorcaserin for weight loss?

In the 1 year BLOSSOM trial of 4008 adults, on the dose of 10 milligrams twice a day, 35% of participants lost 10% of their weight as compared to only 16% on placebo. The average weight loss in this trial on lorcaserin 10 milligrams twice a day was 8% of body weight as compared to 4% with placebo.

When lorcaserin is stopped weight regain is more likely to occur.
That is as expected.
Drugs don't work when you don't take them and obesity is not curable with a drug like pneumonia is with antibiotics.

But weight regain can occur even if lorcaserin is continued. In the earlier BLOOM trial of 3182 adults, of those who lost 5% of their weight at 1 year, 68% maintained that loss at 2 years if they stayed on lorcaserin while 50% maintained that weight loss at 2 years if they were switched to placebo after 1 year of lorcaserin.

In the BLOSSOM trial, those taking lorcaserin had small improvements in blood pressure (3%), triglycerides (9%) and HDL cholesterol (6%). And high sensitivity CRP and heart rate dropped slightly, both good signs.

How about diabetes? About 90% of people with Type 2 Diabetes are overweight. 
Even modest weight loss can be very helpful in improving blood sugars.
In the just published BLOOM-DM trial, 604 adults with Type 2 Diabetes were randomized to placebo or lorcaserin and followed for 1 year.

In BLOOM-DM, at the beginning of the study, all were taking either metformin or sulfonylurea or both for treatment of their diabetes. The average HgbA1c was 8.1% at baseline.
An average of 5.5% weight loss was seen on lorcaserin as compared to 1.7% on placebo.  Of those completing this 1 year trial, 45% on lorcaserin versus 18% on placebo achieved 5% weight loss. And 20% on lorcaserin vs. 6% on placebo achieved 10% weight loss at 1 year.

Many more patients on lorcaserin got to a HgbA1c of 7% or less than those on placebo: 50% versus 26%.

So lorcaserin looks like it could be helpful for overweight or obese adults. But there is no predicting how a person might do with lorcaserin. Some persons may have a great response while others may find it unhelpful. Lorcaserin would seem most appropriate when the excess weight is contributing to other significant medical problems like sleep apnea or diabetes.

And everyone working on weight loss needs to consciously take steps to increase activity and reduce calories.

Lorcaserin will be marketed in the U.S. as Belviq.
Belviq is no miracle drug but it's a step in the right direction for all those suffering with obesity.
It will be good to have this option available.

Saturday, July 7, 2012

Junk Science

Most of what catches your attention on the news amounts to junk science. Junk science is often observational studies. When flawed observational studies show up in the news they worry patients and doctors and cause unnecessary harm. 

Too often, even doctors cannot tell a good study from a flawed one. And sometimes patients, without contacting their doctor, will stop their medicine because of these scary junk science reports.

From Lantus insulin causing cancer to calcium channel blockers causing heart attacks , to alar on apples causing cancer, all these junk science scares have been proven wrong. 
Some of the problems with these studies related to confounders. I discussed confounders in a previous post on diet beverages.

An excellent recent article in the Wall Street Journal nicely states the problems with the every increasing number of these, often junky, observational studies. Observational studies do not provide the high quality data like that from randomized controlled clinical trials. But they are observational studies are easier and cheaper to do.

Of course, not all observational studies are the same. Some are better than others.

Some flawed observational studies had suggested Actos might increase the risk of bladder cancer. We now have updated findings of a good quality cohort study, 
This is the best study on the question of Actos and bladder cancer.

In this study, over 84,000 patients were followed over 8 years. And happily, no statistically significant difference in bladder cancer was seen in the Actos users as compared to those who had diabetes but had not been on Actos.  

Too often the desire to attract readers or viewers takes the place of thoughtful responsible reporting. And some health or science reporters appear severely deficient in the ability to critically think.

My advice is: to remain skeptical, think again and talk to your doctor before believing the medical reports you read or hear.