Information on the Glucose Tolerance Test

I have only been exposed to the glucose tolerance test one time. That was back in the early 1990s. All I know was that I passed the test for what the level for diabetes during that time. Then, I did not know what the level was for being a person with diabetes. I knew what diabetes was and what it could do for people that did not manage their diabetes.

I was lucky because both my mother's parents had type 2 diabetes and my grandfather took some time when I was young to try to explain what type 2 diabetes did to people's body if they did not take care of their diabetes. He and my grandmother did not have any problems that they showed me even though my grandfather used a cane when he went out side of the house.

I know that during holidays when the family gathered there, there was plenty of food for everyone, but grandpa told me he ate sparingly and did not eat bread and I remember him doing this.

Back to the Glucose Tolerance Test or GTT or OGTT (oral) and there are other variations. This is not used as frequently by doctors today and some will not use it. They prefer the HbA1c test and rely almost exclusively on this. Yes, they use a fasting blood glucose test or a plasma glucose test to confirm diabetes, but they seldom use the GTT.

Before taking the test, the patient is asked not to eat for 8-12 hours. A sample of blood will be taken before the test begins. This fasting sample will be used to provide a comparison for the test results.

The individual will then be asked to drink a sugary drink containing a known amount of glucose (most are 75 grams of glucose) and water. The exact timing may vary, but another blood sample may be taken every 30 to 60 minutes for a total of 2 hours.

Here is what the different blood glucose levels may indicate under today's rules:

• Below 140 milligrams per deciliter - normal
• 140 to 199 milligrams per deciliter - impaired glucose tolerance or prediabetes
• Above 199 milligrams per deciliter - diabetes

If the test results do show diabetes, the doctor may choose to repeat the test on another day or use another test to confirm the diagnosis.

Various factors can affect the accuracy of the glucose tolerance test. For the test to give reliable results, the person must be in good health and not have any other illnesses. The person should be relatively active and not be taking any medicines that could affect their blood glucose.

Diabetes is a dangerous disease. According to the Diabetes Research Institute, it affects more than 380 million people worldwide and takes more lives than AIDS and breast cancer combined. It claims the life of 1 American every 3 minutes. It is also the leading cause of blindness, kidney failure, amputations, heart failure, and stroke.

There is currently no cure for diabetes. Early detection and immediate treatment is key to controlling the disease.

Doctors Underestimate Patient Goals

This article in Diatribe really confirmed the attitude of doctors about people with type 2 diabetes for me. I am not surprised, as most doctors believe diabetes is progressive and seem to care nothing about the patients and their well being.

The American Association of Clinical Endocrinologists (AACE) recently conducted an online survey called “Perspectives in Diabetes Care.” The upsetting, but not altogether surprising result was that people with type 2 diabetes claim they are willing to take action to achieve their A1c goals faster than their doctors perceive.

This AACE survey, sponsored by Sanofi, provides evidence to back up patient frustrations, which often escalate as people progress through treatment for chronic conditions. On the face of these results, there appears to be a disconnect in communication.

Of the 1,000 adults with type 2 diabetes surveyed, 55% said they were willing to do more to accelerate progress toward their A1c goal, including more frequent doctor visits and changing medications. Meanwhile, of 1,004 endocrinologists, primary care physicians, and other medical professionals surveyed, only 18% thought people with type 2 diabetes would be willing to make such efforts. That’s an alarming three-fold discrepancy!

Breaking down the data further, 57% of adults with type 2 said they would visit their doctor more often; only 19% of medical professionals believed this to be the case. And, while 52% of people with type 2 diabetes said they’d be willing to make multiple medication changes, only 16% of medical professionals perceived this willingness.

The healthcare system as it stands is based on short (most are 12 to 15 minutes in length), infrequent appointments and doesn’t allow for in-depth, ongoing conversations. Assuming there won’t be a major change in the near future, there are still ways to enhance communication. The following six questions (from the diaTribe guide to individualizing therapy) may be a useful starting point:

• What was your last A1c? How does it compare to the goal you and your healthcare provider are targeting? How has your A1c changed over the last year?
• If you are not at your A1c target, what actions could you take to improve it? Would you benefit by more closely analyzing your blood glucose readings to identify patterns? Do you focus on A1c, daily glucose patterns and glycemic variability, or both?
• Do you frequently experience hypoglycemia? If so, why do you believe these episodes are occurring? What tools or techniques have you considered to reduce this risk, and to monitor it? Does your hypoglycemia limit your daily activities, sense of control, or independence?
• How does your current weight compare to your goal? Has your weight changed recently or over the past year?
• Do you have insurance? How much are you willing to pay out-of-pocket for diabetes therapy?
• What are some of the things that are making it tough to manage your diabetes? Do stress, lack of motivation, or feelings of burnout play a role in your experience with diabetes? If yes, how often?

Problems When Patients Hide Supplements – Part 7

Part 7 of 7 parts.

The clinician should use the clinical encounter to inquire about supplement use and take the opportunity to discuss the benefits and risks of supplements, when/whether they should be taken, and how they compare with prescription and over-the-counter medications. On the basis of the medical history, the clinician should determine whether supplement use is an important issue for a certain patient's health. For example, appropriate supplement use should be discussed with patients for whom the following situations apply:

1. Consuming fewer than 1600 calories per day;
2. Vegans, vegetarians, and anyone eliminating an entire food group from their diet;
3. Pregnant and breast-feeding women;
4. Postmenopausal women and those with heavy menstruation;
5. Chronic diarrhea;
6. Food allergies and food intolerances; and
7. Surgical removal of portions of the digestive tract or bariatric bypass surgery.

Additionally, oncology patients should be warned about the possibility that antioxidative supplements, such as vitamins C and E, can interfere with anticancer medications.

One way to become aware of potential issues with supplement use is through health information technology. Not only can numerous educational programs on supplements be found online, but many search engines also can cross reference different types of medicines, and many of them can easily check for interactions between supplements and other medications. Most office electronic medical record (EMR) systems have software that flags interactions between active ingredients in drugs and supplements. However, given the variability of dietary supplements in the marketplace, EMRs are not foolproof.

For more information about dietary supplements, and herbal medications, look to this for vitamins and minerals under articles. Then look to this for Complementary and Alternative Medicine Guide. Both are good resources for reading about natural medicines that conflict with prescription drugs. Most of the time, these are found near the bottom of the article.

For the first one above I have selected the mineral magnesium and you will need to be down about two thirds of the article under drug interactions to see the problems that it can cause.

For the second one above I have selected the herb Cranberry and about two fifths of the way down at Possible Interactions you will discover problems with Warfarin, Aspirin, and other medications.

This is the reason for the seven parts of this blog series and why we need to be aware of them and not ignore them just because they are natural. Your doctor does need to be aware of these natural drugs.

Problems When Patients Hide Supplements – Part 6

Part 6 of 7 parts.

Doctors and patients can report adverse events, product use errors, and product quality problems associated with dietary supplements through an FDA voluntary online reporting system known as MedWatch. MedWatch is the FDA Safety Information and Adverse Event Reporting Program for reporting serious reactions, product quality problems, therapeutic inequivalence/failure, and product use errors with human medical products, including drugs, biologic products, medical devices, dietary supplements, infant formula, and cosmetics.

If a doctor has a patient that suffered a serious harmful effect or illness after taking a dietary supplement, a healthcare provider can report this by calling FDA's MedWatch hotline at 1-800-FDA-1088 or online at the Medwatch Website. The identity of the patient is kept confidential.

Consumers also can report an adverse event or illness they believe to be related to the use of a dietary supplement. Health professionals and consumers also can check for dietary supplement alerts and safety information at http://www.fda.gov/Food/DietarySupplements/Alerts/default.htm or by contacting the FDA Center for Food Safety and Applied Nutrition Outreach and Information Center at 1-888-SAFEFOOD. Clinician resources can be found online or in software packages for computers and mobile devices, usually as part of an electronic health records package.

With an estimated 50% of the US population using dietary supplements, it is imperative that the clinician always ask about dietary supplements during the clinical encounter. This is particularly important during early encounters when the patient care dyad is being established. The clinician should clearly ask about vitamins, minerals, and botanicals and encourage patients to bring their dietary supplements to clinic visits. The US Preventive Services Task Force recommends including questions about supplement use in the patient education and counseling for prevention section of the clinical encounter.

Clinicians who have regular interaction with patients need to be up to date on current dietary supplement usage patterns in the clinician's patient pool and in the United States in general. NHANES collects the most comprehensive data on supplement use, and studies using NHANES data are likely to provide the most accurate, representative information. A search on PubMed or Google will produce several articles and journals on dietary supplement use patterns among various populations and subgroups in the United States and elsewhere.

The FDA regulates dietary supplements far less stringently than it regulates pharmaceutical drugs. Because of this disparity in regulation, patients could be taking supplements that have unreliable amounts of the active ingredient or those that are adulterated with impurities. Certain geographic areas of the world may be associated with specific patterns of contamination. It is essential, therefore, to understand not only the epidemiology of supplement use patterns but also the sources of the supplements used by the population in order to identify possible side effects or contaminants.

Problems When Patients Hide Supplements – Part 5

Part 5 of 7 parts.

Up to 60,000 cases of ingestion of toxic levels of vitamins occur annually, primarily in children who ingest the vitamins thinking they are candy. Cases are rarely fatal. Table 2 lists the known toxicities of vitamins.

Table 2. Vitamin Toxicity

Vitamin	Symptoms
A (Retinol)	Blurred vision in early stages of toxicity; acute toxicity can cause headache, photophobia, anorexia, nausea, vomiting, abdominal pain, drowsiness, irritability, seizures, and skin desquamation; chronic toxicity can cause erythema, eczema, pruritus, dry and cracked skin, cheilitis, conjunctivitis, palmar and plantar peeling, alopecia, and pain and tenderness in the bones of the extremities
B1 (Thiamine)	Tachycardia, hypotension, cardiac dysrhythmias, headache, anaphylaxis, vasodilation, weakness, and convulsions
B3 (Niacin)	Acute toxicity can cause prostaglandin-mediated symptoms (eg, flushing, wheezing, diarrhea); chronic toxicity can cause jaundice, abnormal liver function tests, and acanthosis
B6 (Pyridoxine)	Signs of sensory neuropathy (eg, paresthesias, ataxia, perioral numbness, impairment of position and vibration senses)
B2 (Riboflavin)	Yellow-orange urine
B5 (Pantothenic Acid)	Diarrhea
B9 (Folic Acid)	Gastrointestinal disorders, sleep problems, seizures; may interfere with some chemotherapy agents
C (Ascorbic Acid)	Renal colic, diarrhea, rebound scurvy in children of women taking high doses, glucose-6-phosphate dehydrogenase (G6PD)-associated hemolysis, dental decalcification, occult rectal bleeding, increased estrogen levels
D (Calciferol)	Acute toxicity can cause muscle weakness, apathy, headache, anorexia, irritability, nausea, vomiting, and bone pain; chronic toxicity can cause acute symptoms and constipation, anorexia, abdominal cramps, polydipsia, polyuria, backache, hyperlipidemia, and hypercalcemia
E (Tocopherol)	Acute toxicity can cause nausea, abdominal cramps, diarrhea, headache, fatigue, easy bruising and bleeding, diplopia, muscle weakness, creatinuria, and poor platelet agglutination
K (Phylloquinone)	Inhibits the effect of oral anticoagulants

Data from US Preventive Services Task Force.

Problems When Patients Hide Supplements – Part 4

Part 4 of 7 parts

Table 1 lists herbal supplements commonly used in the United States, their typical uses and known toxicities, as well as drug interactions of these herbals with prescribed and over-the-counter medications. Table 1 can be used by the clinician as a handy guide to the clinical signs and symptoms of supplement toxicity, including acute and chronic effects of use as well as idiosyncratic effects and interaction with prescription drugs.

Table 1. Uses, Toxicities, and Drug Interactions of Commonly Used Dietary Supplements

Herb	Common Use	Known Toxicities	Drug	Known Drug Interactions
Echinacea	Upper respiratory tract infection		Warfarin	Reduced plasma levels of warfarin
Garlic	Hypercholesterolemia	Chopped garlic at room temperature can result in botulism	Chlorpropamide	Bleeding, increase in international normalized ratio (INR)
Ginkgo biloba	Dementia, cognitive impairment; remedy for impotence and vertigo	Gastric disturbance, headache, dizziness, and bleeding	Warfarin	Bleeding
Saw palmetto	Benign prostatic hyperplasia
Ginseng	Physical performance	Can increase blood pressure	Warfarin	Decrease in INR
Grape seed extract	Venous insufficiency
Green tea	Cancer
St. John's wort	Depression	Can increase blood pressure, causes severe headache	Amitryptyline	Reduced plasma concentrations of amitryptyline
Bilberry	Vision impairment
Aloe	Dermatitis/wound healing (topical)	Excessive amounts may cause a laxative effect
Ma Huang (ephedra)	Weight loss	Hypertension and cardiovascular events
Goldenseal	Cough, upset stomach, and menstrual problems	Can increase blood pressure and cause gastrointestinal distress and nervous system effects
Feverfew	Migraine	Can increase blood pressure
Kava	Anxiolytic, analgesic, muscle-relaxing and anticonvulsant effects	Can potentiate CNS acting substances	Alprazolam	Increased sedation
Prickly chaff powder	Hypercholesterolemia	Bone marrow toxicity, abnormal electrolyte homeostasis
Evening primrose	Premenstrual syndrome, attention-deficit/hyperactivity disorder, diabetic neuropathy	Lowers seizure threshold of various anticonvulsants
Shankhpushpi	Dementia, cognitive impairment		Phenytoin	May have adverse effect on blood levels of phenytoin

Data from Pharmacy Times.

Problems When Patients Hide Supplements – Part 3

Part 3 of 7 parts.

When you read the label of dietary supplements, there is not much to tell you if the quality is good, if there is small amounts of prescription drugs included, or even if the ingredients are correct. The amount of quality control depends on the manufacturer, the supplier of the ingredients, and the workers on the production line.

It is important to know that in 2007, the Food and Drug Administration (FDA) issued the Good Manufacturing Practices (GMPs) for dietary supplements. The GMP is a set of requirements and expectations by which dietary supplements must be manufactured, prepared, and stored to ensure quality. All manufacturers are expected to guarantee the identity, purity, strength, and composition of their dietary supplements.

The goal of the GMP is to prevent the inclusion of the wrong ingredients, the addition of too much or too little of a dietary ingredient, the possibility of contamination (by pesticides, bacteria, heavy metals such as lead, etc.), and the improper packaging and labeling of a product.

The widely inclusive definition of dietary supplements makes assessment of user prevalence difficult. Whereas some authors limit their description of supplement use to multivitamins and minerals, others include herbals and botanicals as well. It is recommended that providers consider all dietary supplements, minerals, vitamins, and herbals that patients might be taking.

The most often quoted rates of supplement use in the United States are from the National Health and Nutrition Examination Survey (NHANES) data. Estimates of supplement use by adults range from 50%-80%. Supplement use is higher in white and Asian populations, in those with high household incomes, and in college-educated persons. Women and older individuals tend to use supplements more often. Other factors related to supplement use include lean or normal body mass index, moderate to vigorous recreational physical activity, no use of tobacco products, and moderate ingestion of distilled spirits and wine.

More than 40% of the population report taking multivitamins, the most common vitamin product used. More than 20% of the population also report use of vitamins C and E, and 10% report use of vitamin B. Vitamin D use has increased in recent years because evidence suggests that it may be essential to health beyond calcium homeostasis.

Calcium is the most commonly used mineral, with up to 50% of the population reporting use when antacid/calcium combinations are considered. The next most commonly used mineral is iron. Herbals used by more than 5% of the population include echinacea, garlic, ginkgo, ginseng, glucosamine, fish oil, flax seed oil, and St. John's wort. Use of all food supplements is increasing in most age groups in the United States.