Patients with diabetes mellitus are advised to self-monitor their blood glucose levels; however, checking blood glucose daily is costly, and no evidence supports this practice in patients with type 2 diabetes. The American Diabetes Association says, “Optimal frequency of self-monitoring of blood glucose for patients with type 2 diabetes is not known, but should be sufficient to facilitate reaching glucose goals.” Karter and associates conducted a cohort study to determine the effectiveness of self-monitored blood glucose levels in improving glycemic control, even in patients with type 2 diabetes.

Patients who were enrolled at the Kaiser Permanente Medical Care Program of northern California were included in the study if they had a diagnosis of diabetes mellitus, at least one glycosylated hemoglobin (HbA_1c) measurement greater than 6.7 percent, and full pharmacy benefits (to enable complete strip utilization). Patients were categorized according to type of diabetes (if unclear, they were excluded) and the number of times theyself-monitored their blood glucose and HbA_1c levels.

There were 23,412 patients included in the study. Patients with type 1 diabetes (34 percent [395 of 1,159]) or insulin-treated type 2 diabetes (54 percent [3,011 of 5,552]) were more likely to self-monitor their blood sugar levels at the recommended frequency than patients with non–insulin-treated type 2 diabetes (20 percent [2,543 of 12,786]). Patients who were adherent to the recommended monitoring schedule were more likely to have healthy lifestyle behaviors, to use self-care practices other than self-monitoring, to obtain appropriate annual screenings, and to have significantly lower HbA_1c levels. Patients who observed the recommended monitoring frequency (at least three times daily in patients with type 1 diabetes and at least once daily in patients with type 2 diabetes) had better glycemic control.

The authors conclude that following recommendations for glucose monitoring is associated with better control of diabetes. Since this was a cohort study, causality cannot be determined, but the study provides some support for recommending self-monitoring of blood glucose levels in patients with type 1 and type 2 diabetes.