3.4.0.0 For Patients Using Basal Insulin and/or Oral Agents
The evidence is insufficient regarding when to prescribe SMBG and how often testing is needed for insulin-treated patients who do not use intensive insulin regimens, such as those with type 2 diabetes using basal insulin with or without oral agents. However, for patients using basal insulin, assessing fasting glucose with SMBG to inform dose adjustments to achieve blood glucose targets results in lower A1C (47,48).
In people with type 2 diabetes not using insulin, routine glucose monitoring may be of limited additional clinical benefit. For some individuals, glucose monitoring can provide insight into the impact of diet, physical activity, and medication management on glucose levels. Glucose monitoring may also be useful in assessing hypoglycemia, glucose levels during intercurrent illness, or discrepancies between measured A1C and glucose levels when there is concern an A1C result may not be reliable in specific individuals. However, several randomized trials have called into question the clinical utility and cost-effectiveness of routine SMBG in noninsulin-treated patients (49–52). In a year-long study of insulin-naive patients with suboptimal initial glycemic control, a group trained in structured SMBG (a paper tool was used at least quarterly to collect and interpret seven-point SMBG profiles taken on 3 consecutive days) reduced their A1C by 0.3% more than the control group (53). A trial of once-daily SMBG that included enhanced patient feedback through messaging found no clinically or statistically significant change in A1C at 1 year (52). Meta-analyses have suggested that SMBG can reduce A1C by 0.25–0.3% at 6 months (54–56), but the effect was attenuated at 12 months in one analysis (54). Reductions in A1C were greater (-0.3%) in trials where structured SMBG data were used to adjust medications but not significant without such structured diabetes therapy adjustment (56). A key consideration is that performing SMBG alone does not lower blood glucose levels. To be useful, the information must be integrated into clinical and self-management plans.