Glucose tolerance test can clear up confusing A1c results
Q: I’m confused by the relationship between my blood glucose level and A1c. My blood glucose has crept up from 100 to 112 in one year after I started taking 40 mg of atorvastatin. My A1c level is 5.1 percent, apparently “normal,” so my doctor is unconcerned about the blood glucose reading.
When is it time to become concerned? When my blood glucose goes up another 15 points and brands me as diabetic? Does A1c “trump” blood glucose results to the degree that the blood glucose test can be disregarded? If so, why even bother to test blood glucose?
A: Diabetes can be diagnosed by blood sugars, which are a “snapshot” of blood sugar in time; by an A1c test, which looks at blood sugar averages over the last few months; or by a glucose tolerance test, which is a stress test on your pancreas’ ability to make insulin in response to a sugar load.
The A1c is most commonly used and is also used to monitor blood sugar in people with diabetes. A level of 5.1 percent is normal, between 5.7 percent and 6.4 percent is considered prediabetes, and 6.5 percent and higher is considered diabetes.
People can have diabetes with a normal A1c, and even with normal fasting blood sugars. The glucose tolerance test is the most sensitive test for most people, since high blood sugar after eating usually happens long before high fasting sugars.
Blood sugar may be high for only a short period, so the A1c can be near normal. However, it would be very unusual to see an A1c of 5.1 percent in a person newly diagnosed with diabetes. It could happen if the change in blood sugar is very recent.
I hope your doctor really is concerned, even if they aren’t showing it. Atorvastatin can increase blood sugar, although not usually enough to make someone cross over into diabetes territory. The few times I order a glucose tolerance test are in cases like yours, where the blood sugars are at odds with the A1c level.
Q: My husband was prescribed Singulair by his allergist and took it for two years. At the end of that time, he was diagnosed with depression and memory loss. His neurologist advised that he shouldn’t take it, but his pulmonologist recommends it. Do you take the FDA warnings about the drug seriously? Most doctors don’t know about them.
A: Montelukast (Singulair) is commonly used for asthma and allergic rhinitis. I agree with you that many physicians are not aware of the boxed warning, which reads:
“Serious neuropsychiatric (NP) events have been reported with the use of montelukast. The types of events reported were highly variable and included, but were not limited to, agitation, aggression, depression, sleep disturbances, and suicidal thoughts and behavior (including suicide). The mechanisms underlying NP events associated with montelukast use are currently not well understood.”
Physicians should take boxed warnings very seriously. That’s not to say this beneficial drug should not be used, but the FDA says, and I agree, that a person should be monitored for events like your husband’s. New depression while on this medicine should prompt discontinuation. Any type of depression, especially in older people, can be associated with memory changes.
I can’t say for sure whether your husband’s issues are caused by Singulair, but I would consider the neurologist’s advice to discontinue it to see whether he improves. The best estimate I could find for depression was that less than 1 percent of people on this medicine were diagnosed with depression severe enough to warrant prescription drug treatment in the first year of taking it.
Q: My 30-year-old and otherwise healthy grandson has been suffering from and treating hemorrhoids for two years. He is anemic due to his loss of blood. He’s had several bandings; they couldn’t complete the last one because he was in too much pain. They said they couldn’t anesthetize the area because his lack of feeling would prevent them from knowing if they were near a nerve. So, now they say he should have surgery, although it is said to be quite painful and difficult.
Do you agree that they can’t anesthetize the area for banding, and is the surgery as horrible to deal with as they say? Under what conditions would you say it is advisable to have the surgery?
A: Most people with a banding procedure do not need anesthesia, and nerve blocks are not used in hemorrhoidal banding because a feeling of pain is a useful indication that the band is not in the best position. When home treatments and office procedures (like banding, scleral therapy or infrared coagulation) are ineffective or can’t be used, it is time to consider surgical treatment.
The surgery’s reputation of being “horrific” is undeserved. I have had several patients in the last few years undergo this surgical procedure, and although they have certainly had a few days of pain after the procedure, all have been happy with the outcomes. Surgeons often use long-acting local anesthetics, and the pain is greatly reduced when they are combined with better surgical procedures, compared to older surgical techniques and anesthesia.
Q: My sister’s dog ran through a swampy area while we were on a walk and ended up with a lot of ticks. We picked off about 10 that day.
The interesting part was that the dog had just gotten his flea and tick medication. So, aside from the first couple of ticks we picked off, the rest were dead, showing the effectiveness of the medicine!
Is there a reason that people, especially those who work or live in areas prone to ticks, cannot be treated in a similar way in order to ward off Lyme and other tick-borne diseases? (I am not suggesting using veterinary medicine on people; I’m just asking why there isn’t a similar medical treatment for people when there’s such an apparently effective preventative for dogs.)
A:
I’m, of course, not a veterinarian, but I did look up the toxicity for three of the most frequently prescribed oral flea and tick medicines for dogs. All of them have the potential for toxicity in humans, and none have been studied extensively. I hypothesize that the cost of conducting studies on humans is so great — and the expected demand for such a product is so low — that drug companies have not thought it worth the costs to proceed.
In the meantime, there are topical treatments humans can spray on the skin to repel ticks, which — in combination with protective clothing and daily tick checks — is a moderately effective way of preventing tick-borne diseases such as Lyme disease, ehrlichiosis and babesiosis. There currently isn’t an available vaccine for Lyme disease, but at least one is undergoing clinical trials now.
Dr. Roach regrets that he is unable to answer individual letters, but will incorporate them in the column whenever possible. Readers may email questions to ToYourGoodHealth@med.cornell.edu or send mail to 628 Virginia Drive, Orlando, FL 32803.