Objective: To evaluate once- and twice-daily self-monitored blood glucose testing strategies in assessing glycemic control and detecting hypoglycemia or hyperglycemia in patients with stable insulin-treated type 2 diabetes.
Research design and methods: Subjects with stable insulin-treated type 2 diabetes monitored blood glucose four times daily (prebreakfast, prelunch, predinner, and bedtime) for 8 weeks. We correlated mean blood glucose values with HbA(1c) measured after 8 weeks and determined the number of hypoglycemic (< or =3.33 mmol/l) and hyperglycemic (> or =22.20 mmol/l) readings captured at the various testing times.
Results: A total of 150 subjects completed the monitoring period; their average age was 67 years, 90% were men, and the mean HbA(1c) at baseline was 8.0 +/- 1.8%. The overall correlation of glucose testing and HbA(1c) was 0.79 (P < 0.0001). Mean blood glucose values for each of the four once-daily testing strategies were significantly correlated with HbA(1c) (r = 0.65-0.70, P < 0.0001), as were mean blood glucose values for each of the six twice-daily testing strategies (r = 0.73-0.75, P < 0.0001). The prebreakfast/prelunch measurements captured the largest proportion (63.6%) of the hypoglycemic readings, the predinner/bedtime measurements captured the largest proportion (66.2%) of hyperglycemic readings, and the prelunch/predinner measurements captured the largest proportion (57.7%) of all out-of-range readings.
Conclusions: Twice-daily testing strategies, particularly prelunch/predinner, effectively assess glycemic control and capture a substantial proportion of out-of-range readings. However, personal testing strategies will vary depending on an individual's risk for hypoglycemia and hyperglycemia.