Evaluating once- and twice-daily self-monitored blood glucose testing strategies for stable insulin-treated patients with type 2 diabetes: The diabetes outcomes in veterans study

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 (≤3.33 mmol/l) and hyperglycemic (≥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.