Diabetic Home Care and Monitoring

The main goal of diabetes care is to control blood glucose levels in order to prevent the serious complications of diabetes.

Diabetes mellitus is a condition in which the body produces no insulin (type 1 diabetes) or insufficient insulin (type 2 diabetes).

• Insulin is a chemical (hormone) produced and secreted by the pancreas. Insulin is essential for all parts of the body to properly store and use nutrients (glucose, proteins, and fat).
• Insulin helps the nutrients to enter the cells of the body. Insulin allows cells to transfer sugar (glucose) from the blood into cells, and this glucose is used to generate the energy necessary to fuel cellular activities.

When insulin is absent or ineffective, cells import inadequate amounts of glucose, a starvation process that causes the liver to release more glucose into the blood in an attempt to feed other tissues. Since this additional glucose still cannot enter the cells, glucose levels in the blood rise. As this glucose-rich blood is filtered by the kidneys, excess sugar enters the urine, accompanied by extra water. High levels of sugar in the blood and urine cause the symptoms and signs of diabetes, such as frequent urination and excessive thirst.

The appropriate treatment for an individual depends on the type of diabetes and its severity. The goal of therapy is to control blood glucose levels, in order to prevent the immediate signs and symptoms of high blood glucose levels (hyperglycemia), as well as prevent the long-term complications of type 2 diabetes.

Type 2 diabetes is managed with a combination of exercise, diet and medication. It is first treated with weight reduction, diabetic diet, and exercise. When these measures fail to control the elevated blood sugars, oral medications are used. If oral medications are still insufficient, insulin therapy, or other newer injectable therapies are considered.

What is the most effective management for a type 1 diabetic? Type 1 diabetes mellitus requires insulin in addition to exercise, and a diabetic diet.

Regular aerobic exercise improves blood circulation and lowers blood glucose levels. Exercise also strengthens the heart and helps maintain an ideal body weight. The chosen aerobic exercise should use large muscle groups. Running, walking, biking, and swimming are excellent activities for most people. The frequency, type, and duration of exercise depend on the individual's age, treatment goals, and physical ability. An exercise program should be designed with the guidance of a health care professional.

Exercise usually decreases the blood glucose levels. If blood glucose is low or normal, exercise may cause hypoglycemia (low blood glucose) due to the utilization of glucose by the active muscles. Therefore, food intake and insulin doses should be adjusted based on the intensity and duration of the anticipated exercise.

Proper nutrition is critical to the management of all forms of diabetes. Some people with type 2 diabetes can control their disease with diet and exercise alone. The right nutrition can help control blood glucose levels, reduce blood cholesterol, maintain optimal body weight, and delay the complications of diabetes. Like exercise, diet therapy is tailored for each person. A successful diet should ideally consider the person’s ethnic background, financial situation, and lifestyle. It also should be simple, since it may be more difficult to follow diet plans with complex rules or food exchanges.

People with diabetes are often advised to use alternative (artificial) sweeteners. Sweeteners are either nutritive or non - nutritive. Nutritive sweeteners, such as sorbitol and fructose, provide calories but may not raise blood glucose levels as much as regular sugar. Non-nutritive sweeteners - such as sucralose, saccharin, and aspartame - do not contain significant calories. Both types of sweeteners are acceptable, but the caloric content of the nutritive sweeteners should be considered when calculating the daily intake of calories. In addition, large quantities of sorbitol can cause diarrhea, and fructose contributes to some diabetic complications.

Medications to treat diabetes are available only by prescription. Insulin must be given by injection or infusion beneath the skin. Oral medications are available that increase the release of insulin from the pancreas and/or increase the responsiveness of the body's cells to the insulin naturally produced by patients with type 2 diabetes.

It can't. Patients with type 1 diabetes have stopped making insulin and thus must take insulin.

The goal of diabetic therapy is to control blood glucose levels and prevent diabetic complications. Glucose levels are lowered into a normal range, if possible, but it is important not to reduce the levels to abnormally low levels that can cause symptoms of hypoglycemia such as sweating, increased heart rate, and even loss of consciousness. Therefore, it is necessary not only to treat the diabetes, but also to monitor the effects of treatment on blood glucose levels to avoid overtreatment or undertreatment of diabetes.

There are two types of tests for blood glucose monitoring in the home. The first type uses a reagent strip, and the second type uses a reagent strip and a glucose meter.

Glucose and ketones also can be measured in the urine. Ketoacidosis is a serious but preventable complication caused by inadequate treatment of diabetes. This condition can be identified by testing urine for ketones.

Self-monitoring of blood glucose is the most important tool available to a patient for determining their glycemic control. This test is simple to perform. It involves taking a small lancet to poke a finger. Usually, this testing is performed just off to the side of the finger's tip, although some meters do allow testing at other sites, such as the forearm. Then, a small quantity of blood is placed on a testing strip that has been inserted into a meter that reports the glucose value.

The meter determines the blood glucose level by measuring the chemical reaction on the reagent strip. Results obtained using a glucose meter are more accurate than those obtained without the meter (that is, with reagent strips alone). However, the results using a home meter vary as much as 20% from the more accurate measurements in a hospital or clinical laboratory. Fortunately, portable meters are accurate enough for home monitoring and self-adjustment of insulin doses at home.

It is important to know that reagent strips are calibrated for specific meters. Many meters need to be calibrated each time a new box of test strips is used. Inappropriate calibration will lead to errors in glucose readings. Using incompatible strips and meters will give unreliable glucose readings.

Errors can also be caused for the following reasons:

• Meters are improperly calibrated
• The meter is dirty
• The battery in the meter is dead
• Reagent strips are stored improperly
• The reagent strips have expired
• Not enough blood is applied to the reagent strip
• Blood is not left on the reagent strip long enough, or is left too long, before reading
• The test is performed under the wrong conditions of temperature and humidity
• Patients are dehydrated

The main advantage of self-monitoring blood glucose is its immediate feedback. The immediacy of the result allows the individual to make decisions in terms of insulin, diet, and exercise that immediately improve glucose control. This, in turn, gives people more control over their diabetes and allows them to adapt their diabetes treatment plan to their lifestyle. Providing regular results to a health care professional allows for more frequent and therapeutic adjustments of medications. This improves symptoms and diabetic control, especially in the outpatient setting.

The main disadvantages of the self-monitoring of blood glucose are cost, discomfort, and inconvenience (such as interrupting one's usual activities to do it). In addition, some patients experience a feeling of frustration at seeing high blood glucose results when they expected lower readings. One could say, "The thing about blood testing is that I know what my sugar is, and the bad thing about glucose testing is that I know what my sugar is."

The information obtained from self-monitoring blood glucose is valuable to all people with diabetes, even those controlled with diet and exercise, and those who require oral medication. Many physicians routinely give all their patients with diabetes a glucose meter, along with an individualized testing schedule. This schedule ranges from once daily up to six times each day, depending on patient needs. Introducing the self-monitoring of blood glucose is effective, in conjunction with diet education.

Many meters are available on the market and differ in attributes. They vary in the amount of blood used, speed to display results, font size of the display, ability to store readings in memory, and capability to download data. Some meters no longer require calibration. Newer meters function as a portable digital assistant (PDA) for health, allowing patients to enter other laboratory values, dates, and results of health visits. Newer meters may also store the strips right in the meter, thereby allowing the patient to avoid handling the strips. They may also allow for a patient to flag readings taken after eating vs. before a meal. Examples of glucose meters available over-the-counter are Accu-Chek III®, Glucometer Elite XL®®, and One Touch Ultra.

Software programs and mobile applications are also available that can help people with diabetes manage their glycemic control. Depending upon the program, users can store and chart glucose levels, lab values, doctor visits, or other health parameters.

The American Diabetes Association has the set the recommendations for health care professionals on what they should be doing, and what should be available for the optimal care of patients with diabetes. Among these recommendations are occasional monitoring of blood glucose either by fingerstick or through a venipuncture (for clinical laboratory testing). Such assessment can be used to supplement the information obtained from the patient's home glucose monitoring, or to verify portable meter testing in the office. Office testing allows the health care professional to see if the patient's results at home are accurate.

Reagent strips are saturated with glucose oxidase, an enzyme that interacts with glucose. When a drop of blood is placed on the strip, the glucose oxidase chemically reacts with the blood glucose. The resultant reaction changes the color of the strip. The higher the glucose level, the greater the reaction, so the more dramatic the color change. The blood glucose level can be determined by comparing the color of the strip with a color chart. For accurate results, test strips should be stored at room temperature and away from moisture. To protect the strips from moisture, bottles should be closed after use.

The disadvantage of reagent strips alone is that they do not give an exact glucose measurement. They are accurate enough, however, to alert patients to seriously high or low levels of glucose. Examples of reagent strips available over–the–counter (OTC) are Chemstrip bG® and Glucostix®. To determine a more accurate blood glucose level, the reagent strip must be combined with a blood glucose meter. (See below.)

The role for testing urinary glucose at home has faded with universal blood glucose monitoring by fingerstick. Those few patients who choose to test urinary glucose must realize its limitations. Urinary glucose only estimates blood glucose values roughly, and it provides no information at all unless there is glucose in the urine. Glucose appears in the urine when the blood glucose level is over 180 mg/dL, well above the target for most patients. Below that level, urinary glucose is usually negative.

Urinary glucose levels should not be confused with checking urinary microalbumin and related protein levels. Urinary glucose levels should not be confused with checking urinary microalbumin and related protein levels. Performed in the doctor's office at least annually, these tests provide necessary information about kidney function the basis for determining whether certain medications should be added to the treatment plan to protect kidney function.

Urinary glucose tests also do not indicate the current blood glucose level, but rather the glucose level during the period of time between the collection of the urine and the previous urination. In many patients, the level of blood glucose must be very high in order for glucose to appear in the urine. Therefore, the urine may be free of glucose, despite unacceptably high blood levels of glucose. Thus, results from urine glucose tests should not be used to adjust insulin doses.

There are two types of urine glucose tests. Both types rely on a chemical reaction that produces a color change. These tests use either tablets or strips. Generally, the test strip or tablet is placed in urine. The resulting color change is matched against a color chart provided by the manufacturer, which shows the different colors produced by different levels of glucose.

The first type, called the copper reduction test, uses cupric sulfate (for example, Clinitest). In the presence of glucose, cupric sulfate (which is blue) changes to cuprous oxide (green to orange). The reaction should be observed closely and the manufacturer's instructions closely followed. The copper reduction tests can react with substances other than glucose in the urine, leading to false positive results. This means the test erroneously shows glucose when it is not present. Examples of these other substances include aspirin, penicillin, isoniazid (Nydrazid, Laniazid), vitamin C, and cephalosporin-type antibiotics. Tablets and solutions utilizing copper reduction may damage the skin and are poisonous if ingested. They should be handled carefully and kept out of the reach of children.

The second type of urine glucose test, called the glucose oxidase test, uses the chemical toluidine and the enzyme glucose oxidase (for example, Clinistix). Glucose oxidase converts the glucose in urine to gluconic acid and hydrogen peroxide. The interaction of the hydrogen peroxide with the toluidine causes a change in color. False negative results (meaning the test shows no glucose when glucose really is present) may occur in patients taking vitamin C, aspirin, iron supplements, levodopa (Sinemet), and tetracycline-type antibiotics. Glucose oxidase tests are more convenient to use and less expensive than copper reduction tests. The strips should be kept away from moisture.

Ketone testing is an important part of monitoring type 1 diabetes. It is a tool that is often also used in pregnancies that are complicated by diabetes (called gestational diabetes).

Ketones form when one fasts (for example, while sleeping overnight) or when there is a profound lack of insulin. When the body produces insufficient insulin, its cells cannot adequately remove glucose from the blood, and the level of glucose in the blood rises. Responding to what appears to be a lack of glucose, cells release hormones to stimulate the body to produce larger amounts of glucose. Rising blood glucose level causes more urination and dehydration. Due to low insulin action, the liver produces ketones, which are acids released into the blood. The presence of ketones signals a condition in diabetic patients called diabetic ketoacidosis (or DKA). Ketoacidosis always signifies that the cells are not receiving enough insulin.

Severe DKA is a medical emergency, since it can result in loss of consciousness and even death. About 0.1% of those with DKA die as a result of it. There is a correlation between high blood glucose levels, dehydration, and ketones. The higher the glucose level, the more likely that ketones will be made. Therefore, diabetic patients with any blood glucose level over 240 mg/dL should test promptly for urinary ketones. Patients with type 1 diabetes should also test for ketones during any acute illness and during severe stress. Also, urinary ketones should be checked if any symptoms of DKA occur (such as nausea, vomiting, abdominal pain, or increased thirst).

Ketones can normally be found in the urine. For example, after an overnight fast, ketones can be seen in up to 30% of people without diabetes. However, these levels of ketone production are usually below the threshold of measurement by the ketone test strips. The strips can give falsely positive results when patients are on drugs such as captopril (Capoten). Falsely negative readings may be seen when test strips are old, exposed to air, or if the urine is very acidic (for example, after drinking a lot of orange juice, which is also high in vitamin C).

These tests are based on the color change that occurs when ketones react with sodium nitroprusside or similar compounds. The tests are performed in a manner similar to that of urinary glucose testing. Different tests detect the three types of ketones (named acetoacetic acid, acetone, and ß-hydroxybutyric acid). For example, Acetest only detects acetoacetic acid and acetone, but not ß-hydroxybutyric acid. Ketostix detects only acetoacetic acid, which can produce false-negative results if only acetone and ß-hydroxybutyric acid are present in the urine. Ketone tests are supplied as strips or tablets.

The American Diabetes Association advises that ketone testing materials be available in the office setting and that physicians should prefer using blood ketone measurements over urine ketone measurements if possible. Home testing for blood ketones is also available, though not often used due to higher cost of the test strips.

The Food and Drug Administration has approved clinical use of Continuous Glucose Monitoring Sensors (CGMS). The first generation of these devices functioned like a Holter monitor of the heart. Now, a small cannula is inserted into the superficial tissue of the abdomen (the subcutaneous tissue). The introducing needle is removed, leaving the sensor to be taped in place then connected to an external device about the size of a digital pager. This records glucose values at an interval of roughly 5 minutes over a 72-hour period. At the end of that period, the recorded glucose values are downloaded, and information is reviewed with a health care professional. Patients usually keep a log over the 72-hour period of how they feel, what they eat, and what their fingerstick readings are for comparison with the sensor data. These data are especially helpful for athletes, patients with unpredictably high or low blood sugar levels, and those who cannot find a pattern to their fingerstick glucose readings. The drawback to the original sensors was that the data were not available in a "real time" format. As a result, the patient would have to bring the device into the health care professional's office to download and review the data in conjunction with the logs they were keeping.

CGM systems have improved dramatically in the last few years. They represent useful tools for diabetic patients to gain insight into their patterns of glucose response and to tailor more individual treatment regimens. The newest generation sensors provide a real time glucose value to the patient. The implantable sensor communicates wirelessly with a pager-sized device that has a screen. The device is kept near the sensor to allow for transfer of data; however, it can be a few feet away and still receive transmitted information. Depending on the model, the screen displays the blood glucose reading, a thread of the readings over time, and a potential rate of change in the glucose values. These sensors can be programmed to "beep" if blood sugars are in a range that is selected as too high or too low. Some can provide a warning alert if the drop in blood sugar is occurring too quickly.

Recent developments have produced one new sensor designed to communicate directly with the insulin pump. While the pump does not yet respond directly to information from the sensor, it does "request" a response from the person wearing the sensor if there is a need to adjust insulin, according to the sugar patterns which the sensor has been programmed to detect. The ultimate goal of this technology is to "close the loop" by continuously sensing what the body needs, then responding by providing the appropriate dose of insulin. While this technology needs further development, strides in this direction continue to be significant and encouraging. There is now one sensor that communicates with a pump to have it suspend insulin infusion for 2 hours, if there is a downward trend in blood glucose that could lead to hypoglycemia.

The hemoglobin A1c test (HbA1c) is crucial to monitor blood glucose control in patients with diabetes. In brief, hemoglobin A1c is the final product of several chemical reactions that occur in the bloodstream as red blood cells are exposed to glucose. A red blood cell typically lives for about three months, so the HbA1c reading provides a report card averaging blood sugar levels over the prior three months. Many different methods are available to determine the HbA1c level. Regardless, HbA1c level has been shown to predict the risk for developing complications of diabetes, much in the same way that cholesterol levels are predictive of heart disease. The HbA1c test should be performed routinely at three-month intervals in patients with established diabetes. HbA1c can be tested when a new case of adult diabetes is suspected, although its use to diagnose borderline pediatric diabetes is still controversial.

To measure HbA1c, blood obtained in the usual way (from a vein) can be sent to a laboratory. Alternatively, many clinics specialized in diabetes care now have desktop HbA1c machines, which will read a simpler fingerstick blood sample within minutes. Several conditions can affect HbA1c measurements, and most relate to disorders of the red blood cells. For example, results may be falsely low if too few red cells are present (anemia). Falsely low readings can occur when red blood cells lose their proper shape (due to conditions like thalassemias, sickle cell disease, or spherocytosis). HbA1c is invaluable as a tool to individualize patient care plans so that glycemic goals can be achieved.