Home monitoring of blood glucose and blood pressure levels can provide patients and physicians with valuable information in the management of diabetes mellitus and hypertension. Home monitoring allows patients to play an active role in their care and may improve treatment adherence and clinical outcomes. Glucose meters currently on the market produce results within 15 percent of serum blood glucose readings and offer a variety of features.

Although the data are somewhat conflicting, home glucose monitoring has been associated with improved glycemic control and reduced long-term complications from diabetes. These effects are more pronounced in patients who take insulin. Home blood pressure values predict target organ damage and cardiovascular outcomes better than values obtained in the office.

Home blood pressure measurements are also effective at detecting borderline hypertension and monitoring the effectiveness of antihypertensive drugs. Validated arm cuffs are the preferred blood pressure devices for home use. Information from home monitoring should always be used in conjunction with that from regular office visits and other data to make appropriate therapeutic decisions. (Am Fam Physician 2007;76:255-60, 261, 262. Copyright © 2007 American Academy of Family Physicians.)

Home monitoring of blood glucose and blood pressure levels can provide the patient and physician with valuable information for disease management. Because a variety of home monitoring devices are available, appropriate selection and use can be a daunting task. This article reviews devices for home monitoring of glucose and blood pressure and discusses their clinical utility.

Glucose Monitoring

Although there is no universal standard for accuracy of glucose meters, several groups have defined acceptable ranges.1-4 The U.S. Food and Drug Administration (FDA) requires glucose meters to produce self-monitoring results within 20 percent of a reference measurement but recommends results within 15 percent4; the FDA has stated that future meters should achieve results within 10 percent of reference at serum glucose concentrations of 30 to 400 mg per dL (1.7 to 22.2 mmol per L). The American Diabetes Association (ADA) recommends that meters produce readings within 5 percent of laboratory values.1 All meters currently on the market are considered to be clinically accurate in that they at least meet the FDA standard, although it is important to remember that they are not as accurate as a standard laboratory test.5,6 Given this broad range of possible error, making treatment decisions based solely on self-monitoring of blood glucose (SMBG) is not advised.

Glucose meters are most accurate when used properly.7 Thus, educating patients on proper use and what to do with the results is vital. Although the exact procedure for using a meter varies by product, potential pitfalls are similar. Common errors include poor maintenance (e.g., soiled meter), using expired test strips, obtaining an inadequate sample size, and failing to calibrate the meter.

Clinical utility

Uses of SMBG data include identifying and treating hyper- and hypoglycemia; making decisions about food intake or medication adjustment when exercising; determining the effect of ingested food on blood glucose; and managing glucose fluctuations resulting from illness. Although the data are somewhat conflicting, larger, better-designed trials have shown that SMBG improves glycemic control when the results are used to adjust therapy. However, the data for reducing long-term complications are more conclusive for patients on insulin therapy.

Although the optimal frequency of monitoring is unknown, the ADA recommends SMBG three or more times a day for patients with type 1 diabetes. Patients with type 2 diabetes still benefit from at least periodic monitoring. Ultimately, the frequency and timing of SMBG should be determined by how the data will be used. SMBG can assist the patient and physician with adjusting diet and medications and maintaining appropriate glucose control. More frequent monitoring is beneficial during insulin dose adjustments. Postprandial monitoring is important to identify the effect of various foods on glucose levels and to monitor the effects of preprandial medications. Other factors, such as desire for tight control and current degree of control, will influence frequency of monitoring.
_{JAMES R. TAYLOR, PharmD, CDE, and KENDALL M. CAMPBELL, MD, University of Florida, Gainesville, Florida}

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