US Pharm. 2008;33(5)(Diabetes suppl):10-16.

According to the Centers for Disease Control and Prevention, approximately 20.8 million people in the United States--7% of the population--have diabetes mellitus.¹ Worldwide, the World Health Organization estimates 180 million people have diabetes, and this statistic will double by the year 2030.² Diabetes mellitus is a group of metabolic disorders characterized by hyperglycemia, resulting from deficiencies in insulin production and/or action. Type 1 diabetes mellitus (T1DM) results from absolute insulin deficiency and individuals require insulin via injection or pump; this classification accounts for 5% to 10% of cases. Type 2 diabetes mellitus (T2DM) accounts for 90% to 95% of diagnosed diabetes cases and results from insulin resistance in which insulin is not properly utilized by the body's cells. For most patients diagnosed with T2DM, treatment options will include weight reduction, exercise programs, nutrition plans, and medications (i.e., oral medications and/or insulin therapy).³

Glycemic Control and Clinical Evidence
Chronic hyperglycemia can result in microvascular and macrovascular complications. Microvascular refers to the small blood vessels and can damage the eyes, kidneys, and nerves; whereas macrovascular refers to the larger vessels, resulting in heart attack and/or stroke. The Diabetes Control and Complication Trial (DCCT) and United Kingdom Prospective Diabetes Study (UKPDS) concluded the benefits of attaining normal glucose concentrations in patients with T1DM and T2DM, respectively.^4-7 The DCCT demonstrated a reduction in the development and progression of microvascular complications by 50% to 75% among patients with T1DM.^4,5 The UKPDS demonstrated a reduction in the development of microvascular complications by 25% among patients with T2DM.^6,7

Based on the DCCT and UKPDS trials, for every 1% decrease in glycated hemoglobin (A1C), there is a 21% reduction in death related to diabetes and 25% to 37% reduction in microvascular complications.^4-7 In addition to long-term complications, hyperglycemia can result in acute complications, poor wound healing, infections, and symptoms. In order to achieve desired glycemic goals, lifestyle modifications (i.e., weight reduction, exercise programs, nutrition plans) and pharmacological therapy will be required. It is important for patients to take an active role in their diabetes management by monitoring glucose concentrations.

Self-Monitoring and Glycemic Goals
The cornerstone of an individual's diabetes management is glycemic control, including prevention of hypoglycemic and hyperglycemic reactions. The two primary techniques available for assessing glycemic control are self-monitoring of blood glucose (SMBG) and A1C measurement. Overall, SMBG allows the patient to monitor glycemic control on a "day-by-day" basis, while an A1C measurement is a blood test determining the average blood glucose concentration over a two- to three-month period.

SMBG has become the gold standard for outpatient diabetes management and short-term assessment of glycemic control. For most patients, it is important to obtain as many points as possible to determine an individual's constant glycemic control, depending upon glycemic goals and medication regimen. Self-monitoring allows for immediate feedback to the patient and is essential to achieving glycemic goals (Table 1).^3,8 In addition, self-monitoring allows the individual to play an integral role in his/her diabetes management. Health care professionals can assess SMBG to determine if medication adjustments or additional glycemic monitoring is necessary.

SMBG can determine if preprandial (before a meal) or postprandial (after a meal) goals are met, detect and prevent hypoglycemic reactions, and evaluate glycemic response to food, physical activity, and medication changes. It is important to discuss SMBG with all patients with either T1DM or T2DM. As a pharmacist, it is essential to inform patients about the proper technique, interpretation of data, and appropriate times to test glycemic response.

According to the ADA, the following recommendations about SMBG are encouraged: 1) at least three or more times per day among patients with T1DM, pregnant women, patients using multiple insulin injections or insulin pump therapy; and 2) less frequently among those on noninsulin therapy or medical nutrition therapy.³ The frequency of monitoring is determined by the needs and goals of the patients; therefore, every patient is unique and will have a different regimen for self-monitoring. For patients with T2DM not on insulin therapy, the optimal frequency of SMBG is not known but should be sufficient to facilitate reaching glucose goals.³ Certain situations may permit a patient to monitor glycemic levels more frequently; these circumstances include sensitivity to hypoglycemia, illness, medication changes, physical activity, or dietary changes

Glucometers
The first blood glucose meters (also known as glucometers) were marketed in 1971, but newer, more sophisticated monitors have been developed. For example, the Accu-Chek Voicemate has 20 audio features for patients with diabetes who are blind or have visual impairment.⁹

There are many factors to consider when assisting a patient in the selection of the right glucometer (Table 2 ). Depending on the retail pharmacy or store, the meter could range in price from $50 to $80.^9,10 However, many manufacturers offer rebates and/or coupons. Table 3 lists some of the meters that are available in community pharmacies.^9,11

Calibration : Each glucometer has specific manufacturer's instructions for calibration and using control solutions. For calibration, glucometers may require insertion of a strip or chip when the monitor is purchased; other glucometers may require proper entry of codes based on the vial of strips. If a patient suspects erroneous readings, then a control test should be performed to verify the glucometer and test strips. In addition, the individual should clean the glucometer periodically. When glucometers are used properly and calibrated corrected, glycemic results may vary by 20% in accuracy; pharmacists should inform patients how to interpret the results.^9,10 Some newer models (e.g., Accu-Chek Compact Plus, Ascensia Breeze 2, Ascensia Contour) do not require calibration.

Test Strips: Test strips should be stored at room temperature in their original vial or container. The vial should not be exposed to extreme temperatures, humidity, or light since this improper storage may affect the accuracy. If a patient orders the strips via a mail-order pharmacy, then the order should not be left in the mailbox for days. The individual should check the expiration date on the vial of strips each time a new vial is opened. In addition, it is crucial to code the glucometer for each new vial of strips in order to get accurate readings.

Obtaining a Blood Sample: Obtaining a blood sample via fingerstick may be the most difficult task for some individuals. The patient should clean the hand with warm soapy water to increase blood circulation. An alcohol swap can be used, but the fingertip should dry for approximately one minute to ensure the alcohol has completely evaporated. The lancet device is used to ensure adequate sample size and can be adjusted for puncture depth. The lancet device should be pointed to the side of the "tested" fingertip. Finger pads should not be punctured since this particular area has more nerve endings and would be more painful. To increase blood flow, the "tested" finger can be hung below the heart or massaged from the wrist up to the tested site. Once an adequate sample is obtained, the blood should be quickly placed on the strip.

Plasma Versus Whole Blood: Certain glucometer may report either plasma or whole blood (capillary) glucose concentrations. A majority of glucometers report the glucose values as plasma concentrations, except for the OneTouch Basic and OneTouch SureStep. Plasma concentrations are 10% to 15% higher than whole blood glucose concentrations. ^9,10

Alternate Site Testing: Depending on the individual's frequency of monitoring glycemic response, some patients may complain of soreness in their fingertips and inquire about alternate site testing. Alternate site testing (AST) is allowed at certain times and with certain glucometers. As glucometers have become more advanced and sophisticated, the amount of blood required has lessened. AST is less painful due to fewer nerve endings and common sites include the palm, forearm, upper arm, thigh, and calf (Figure 1).^9,10,12 AST is reliable in a fasting state, two hours after exercise, or two hours after meals. However, AST locations have less capillary blood flow; therefore, these samples may not be reflective of rapidly rising or declining glucose levels.^9,10 At any other time, the glucose levels may be rapidly fluctuating, in which fingerstick readings would be more appropriate and reliable. When a patient has selected a particular glucometer, it is essential to determine if the monitor allows AST. For example, a patient can draw blood from the arm with a OneTouch Ultra glucometer, but can check from the forearm, upper arm, thigh, and calf with the Accu-Chek Active.⁹ Pharmacists have a significant role in patient education regarding SMBG and AST.

Patient Education About Glucometers
Pharmacists have an integral role in educating patients about glucometers beyond calibration, test strips, and AST. It is essential to discuss the sample size required, the time to obtain results, memory manipulation, and replacement batteries. For example, there are several Accu-Chek models, but each meter is not created equal. All Accu-Chek glucometers allow AST except Accu-Chek Complete; however, it has the largest memory capacity (i.e., holds 1,000 glucose readings) among this manufacturer's products.⁹ There are many glucometers available in community pharmacies; it is important for pharmacists in any practice setting to remain knowledgeable about these diabetic devices.

Proper education is very important for SMBG, especially since there are a variety of glucometers. It is important for the patient to understand the importance of self-monitoring. Recall demonstration by the patient would ensure understanding and allow the pharmacist to correct any errors during this observation. Patients should be instructed to record glucose concentrations in a logbook, with time of medications, meals, physical activity, and any hypoglycemic reactions. This information is valuable to the pharmacist and other health care professionals in assessing current diabetes management and determining if a change is necessary.

Continuous Glucose Monitoring Systems
Over the past few years, continuous glucose monitoring has become available as a new technology for assessing glycemic control. The FDA has approved several continuous glucose monitoring systems (CGMS) manufactured by Abbott Diabetes Care, DexCom, and MiniMed; these devices continuously check interstitial glucose concentrations throughout the day and night. CGMS does not replace the glycemic information obtained from a standard glucometer. The CGMS has five main components: 1) monitor, 2) glucose sensor, 3) connecting cable linking the sensor and monitor, 4) docking station, and 5) test plug.^13,14

The monitor resembles a pager and collects the glucose information from the sensor. This component can be attached to the patient's belt or waistline. The patient must calibrate the monitor three to four times a day by performing fingersticks with a standard glucometer taken at different times of the day. Special events (i.e., medication taken, exercise performed, or meals consumed) should be noted. For showering, the patient may place a ShowerPak (a specially designed plastic bag) over the monitor to prevent water damage as it is not waterproof. The sensor consists of glucose-sensing electrodes on a polyurethane tube and rigid introducer needle.¹⁴ The needle is inserted approximately 5 millimeters underneath the skin of the abdomen.¹⁴ The insertion of the glucose sensor is quick and relatively painless. It is important to keep the site of insertion sterile and the adhesive patch firmly placed to prevent the sensor from moving. Depending on the manufacturer, measurements are averaged every five minutes; this glucose information will be transmitted to the monitor wirelessly.

After the glucose information is collected (usually every three days), the sensor will be removed and the information from the monitor will be downloaded into a computer. The monitor is placed on a docking stand and downloaded on a standard computer using the programmed software. A variety of graphs and charts can be printed, revealing patterns of glucose fluctuations.

The main advantage of using CGMS is to identify fluctuations and trends; for example, it can capture unnoticed hypoglycemic reactions or episodes or elevated postprandial readings in an individual. In addition, the pharmacist and other health care professionals would be able to assess glucose concentrations in response to dietary habits, exercise, and medications and make any necessary adjustments.

One study demonstrated the advantage of using CGMS among patients with T1DM in detecting unrecognized hypoglycemia.¹⁵ According to the ADA, CGMS serves as a supplemental tool for detecting hypoglycemia unawareness, but there are no controlled trials demonstrating improved long-term glycemic control.³ Poor reimbursement has been the greatest barrier of the CGMS. Payers are reluctant to provide reimbursement for patients while covering providers' time for device application and education.¹³ Some insurance companies may provide coverage or reimbursement, but certain criteria have to be met such as unrecognized hypoglycemic reactions or suspected postprandial concentrations with elevated A1C and normal fasting glucose concentrations.¹³ Continuous glucose monitoring can be reimbursed by Medicare and may be covered by private insurance plans; inform patients to check with their insurance carrier.

Conclusion
The prevalence of diabetes mellitus continues to rise and is projected to increase over the next several decades. There are a variety of agents available to health care professional for diabetes management; it poses a challenge to pharmacists in selecting and adjusting an individual's therapy in order to achieve short and long-term glycemic levels. The cornerstone to diabetes management is glycemic control. Pharmacists play an integral role in patient education regarding glucometers. Returning to the basics by providing education about glycemic goals, glucometers, self-monitoring techniques, and  CGMS is very important.

REFERENCES
1. Centers for Disease Control and Prevention (CDC). National diabetes fact sheet: general information and national estimates on diabetes in the United States, 2005. Atlanta, GA: U.S. Department of Health and Human Services, CDC; 2005.

2. World Health Organization. Diabetes fact sheet. www.who.int/mediacentre/factsheets/fs312/en/index.html. Accessed February 21, 2008.

3. American Diabetes Association. Standards of medical care in diabetes. Diabetes Care. 2008;30(suppl 1):S12-S54.

4. The Diabetes Control and Complications Trial Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med. 1993;329:977-986.

5. The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Research Group. Retinopathy and nephropathy in patients with type 1 diabetes four years after a trial of intensive therapy. N Engl J Med. 2000;342:381-389.

6. UK Prospective Diabetes Study (UKPDS) Group. Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34). Lancet. 1998;352:854-865.

7. UKPDS 33. Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes. Lancet. 1998;352:837-853.

8. American College of Endocrinologists. Medical guidelines for clinical practice for management of diabetes mellitus. Endocr Pract. 2007;13(suppl 1):1-66.

9. Assemi M, Morello CM. Chapter 47: Diabetes mellitus. In: Berardi RR, McDermott JH, Newton GD, et al, eds. Handbook of Nonprescription Drugs: An Interactive Approach to Self-Care. 15th ed. Washington, DC: APhA; 2006.

10. O'Mara NM. Blood glucose meters. Pharmacist's/Prescriber's Letter. 2005;21:211208.

11. 2008 resource guide. Blood glucose monitoring and data management systems. Diabetes Forecast. 2008;61:RG31-RG48. www.diabetes.org/uedocuments/df-rg-monitors-0108.pdf. Accessed April 16, 2008.

12. Alternate site testing. www.abbottdiabetescare.com/static/content/image/asta_figure.gif. Accessed February 7, 2008.

13. Klonoff DC. A review of continuous glucose monitoring technology. Diabetes Technol Thera. 2005;7:770-775.

14. FDA. Continuous glucose monitoring system. www.fda.gov. Accessed February 20, 2008.

15. Chico A, Rio-Vidal P, Subira M, Novials A. The continuous glucose monitoring system is useful for detecting unrecognized hypoglycemias in patients with type 1 and type 2 diabetes but is not better than frequent capillary glucose measurements for improving metabolic control. Diabetes Care. 2003;26:1153-1157.

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