A study of children and adolescents with type 1 diabetes showed that, after adjustment for multiple confounders, increased SMBG frequency was significantly associated with lower A1C. In the range of 0–5 tests per day, A1C decreased by 0.46% per additional test per day. Increased testing was associated with significantly less DKA and (probably due to reverse causality) significantly more hypoglycemia (55,56).
SMBG accuracy is dependent on both the instrument and the user (57), so it is important to evaluate each patient’s monitoring technique, both initially and at regular intervals thereafter. Optimal use of SMBG requires a proper review and interpretation of the data by both the patient and the provider.
CGM
Real-time CGM through the measurement of interstitial glucose (which correlates well with plasma glucose) is available. These sensors require calibration with SMBG, and CGM users still require SMBG for making acute treatment decisions. CGM devices have alarms for hypo- and hyperglycemic excursions that include absolute level and rate-of-change alerts. A 26-week randomized trial of 322 type 1 diabetic patients showed that adults aged ≥25 years using intensive insulin therapy and CGM experienced a 0.5% reduction in A1C (from ∼7.6% to 7.1%) compared with usual intensive insulin therapy with SMBG (58). Participants aged