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Recommendations Summary

DM: Glucose Monitoring 2008

Click here to see the explanation of recommendation ratings (Strong, Fair, Weak, Consensus, Insufficient Evidence) and labels (Imperative or Conditional). To see more detail on the evidence from which the following recommendations were drawn, use the hyperlinks in the Supporting Evidence Section below.


  • Recommendation(s)

    DM: Blood Glucose Monitoring

    For individuals on nutrition therapy alone or nutrition therapy in combination with glucose-lowering medications, self-monitoring of blood glucose (SMBG) is recommended. Frequency and timing is dependent on diabetes management goals and therapies (i.e. MNT, diabetes medications and physical activity). When SMBG is incorporated into diabetes education programs and the information from SMBG is used to make changes in diabetes management, SMBG is associated with improved glycemic control.

    Rating: Fair
    Conditional

    DM: Frequency of Blood Glucose Monitoring

    For persons with type 1 or type 2 diabetes on insulin therapy, at least three to eight blood glucose tests per day are recommended to determine the adequacy of the insulin dose(s) and guide adjustments in insulin dose(s), food intake and physical activity. Some insulin regimens require more testing to establish the best integrated therapy (insulin, food, and activity). Once established, some insulin regimens will require less frequent self-monitoring of blood glucose (SMBG). Intervention studies that include self-management training and adjustment of insulin doses based on SMBG result in improved glycemic control.

    Rating: Strong
    Conditional

    DM: Possible Need for Continuous Glucose Monitoring or More Frequent SMBG

    Persons experiencing unexplained elevations in A1C or unexplained hypoglycemia and hyperglycemia may benefit from use of continuous glucose monitoring (CGM) or more frequent SMBG.  It is essential that persons with diabetes receive education as to how to calibrate CGM and how to interpret CGM results. Studies have proven the accuracy of CGM and most show that using the trend/pattern data from CGM can result in less glucose variability and improved glucose control.

    Rating: Fair
    Conditional

    • Risks/Harms of Implementing This Recommendation

      SMBG: 

      • Frequent glucose self-monitoring may cause pain and discomfort
      • Individuals should know of proper disposal of hazardous waste

    • Conditions of Application

      SMBG:

      • Persons must receive education and training in order to use the SMBG devices and data correctly.

      CGM:

      • Persons must receive more comprehensive education and training in order to use the CGM devices and data correctly.
      • In order to have accurate glucose readings, individuals using CGM must be able to correctly calibrate the monitors as indicated by the specific device. Calibration must be done when glucose levels are stable (e.g., it should not be done when a person is eating or exercising). Users must also understand the difference in interstitial fluid tests compared to single point measurement of blood tests and lag time. This is especially critical when glucose levels are dropping. To accurately detect and treat hypoglycemia, capillary blood tests should be used.
      • Currently, the Food and Drug Administration has approved CGM for diagnostic use (e.g., tracking trends in glucose levels), not for making treatment decisions. Treatment decisions should be confirmed using a capillary blood glucose test.
      • CGM devices have alarms to alert the user of hypoglycemia. The intent of the alarm is to enable the user to detect when blood glucose levels are dropping and must be verified by single point measurements of blood glucose to confirm hypoglycemia. If hypoglycemia is verified, treatment must be provided. False negative alarms and alarm delays due to lag time are a concern.
      • Reimbursement for medical supplies may be a barrier. 
      • The scope of practice of the RD and the standards of professional performance defines the role of the RD in glucose self-monitoring education. 

    • Potential Costs Associated with Application

      • There are costs involved in the purchasing of blood glucose monitors and supplies. Insurance reimbursement varies from state-to-state. Medicare provides some reimbursement.
      • Although costs vary, educational sessions on how to use the data from self-monitoring of blood glucose are essential.
      • Elevated blood glucose levels (sub-optimal control) or hypoglycemic episodes can lead to costly health complications. The cost of education and supplies is less than that of treating complications.

      • Both the initial and ongoing costs for CGM are high. Limited coverage is available and reimbursement decisions are usually made case-by-case.

    • Recommendation Narrative

      • In subjects with diabetes,  studies have shown that self-monitoring of blood glucose (SMBG) values correlate with A1C values (Brewer et al, 1998; Bonora et al, 2001; Hoffman et al, 2002; Fiallo-Scharer et al, 2005). 
      • Prospective intervention studies in subjects with type 1 diabetes that included self-management training and adjustment of insulin doses based on SMBG showed significant improvement in glycemic control compared to study control group (DAFNE Study Group, 2002; DCCT, 1993).  
      • More frequent SMBG (3 to 8 times daily) was also associated with better glycemic control regardless of diabetes type or therapy (Karter et al, 2001).
      • SMBG, compared to non-SMBG, is associated with greater improvement in A1C when it is a part of a structured education program where subjects use the information to make changes in their management program (Allen et al, 1990; Franciosi et al, 2001; Schwedes et al, 2002; Davidson et al, 2005; Sarol et al 2005). 
      • Evidence on frequency and duration of SMBG is inconclusive (Coster et al, 2000; Harris, 2001; Karter et al, 2001; Meier et al, 2002; Murata et al, 2003; Jaworska et al, 2004; Wen et al, 2004; Franciosi et al, 2005; Martin et al, 2006).
      • Six studies (3 RCTs, 3 time series) using continuous glucose monitoring (CGM) in subjects with diabetes report improvements in glycemic control (Kaufman et al, 2001; Chico et al, 2003; Ludvigsson et al, 2003; Schaepelynck-Belicar et al, 2003; Deiss et al, 2004; Tanenberg et al, 2004).
      • Seven studies (4 RCTs, 2 time series, 1 nonrandomized trial) report improvements in hyper- and hypoglycemic ranges (Schiaffini et al, 2002; Schaepelynck-Belicar et al, 2003; Bode et al, 2004; Garg et al, 2004; Tanenberg et al, 2004; Weintrob et al, 2004; Garg et al, 2006).
      • Data derived from CGM can be used to modify food or insulin therapy that will improve metabolic outcomes; however, it is currently unclear if use of information from CGM will improve metabolic outcomes significantly more than use of information derived from SMBG: two RCTs (Chico et al, 2003; Tanenberg et al, 2004) found that both methods significantly improved A1C; one RCT (Ludvigsson et al, 2003) found that only CGM significantly improved A1C; and one RCT (Garg et al, 2006) found that only CGM significantly reduced hyperglycemia.
      • In a data-gathering study (Fiallo-Scharer et al, 2005), both methods gave similar mean glucose profiles and associations with A1C.
      • Two RCTs (Chico et al, 2003; Ludvigsson et al, 2003) found no significant differences between methods in improving hypoglycemia; however two other RCTs (Tanenberg et al, 2004; Garg et al, 2006) found that CGM reduced duration of hypoglycemia vs. SMBG.
      • Five studies (1 observational, 2 cross-sectional, and 2 case series) present pattern information from the wearing of CGM devices (Boland et al, 2001; Alemzadeh et al, 2003; Manuel-y-Keenoy et al, 2004; Bode et al, 2005; Streja et al, 2005).

    • Recommendation Strength Rationale

      • Conclusion Statements given Grades I and II

    • Minority Opinions

      Consensus reached.