Type 2 diabetes patients, especially those with poor metabolic control or treated with oral hypoglycemic agents (OHA) only are often regarded as being at lower risk of hypoglycemia than type 1 diabetes subjects. We used continuous glucose monitoring system (CGMS) in 69 type 2 diabetes individuals (mean [±SD] age 63±9 years, duration of diabetes 12±7 years, BMI 31.8±5.2 kg/m2, HbA1c 8.4±0.7%, 74% treated with insulin ± OHA, 26% - treated with OHA only, including sulfonylureas) to assess the hypoglycemia prevalence. Each patient underwent blinded CGMS (iPro2, Medtronic) for 5.8±0.8 days, duration of the time spent at blood glucose (BG) <70 mg/dl was determined and expressed as a percentage of total CGMS use time (T hypo). Clinically statistical hypoglycemia (CSH) episodes defined as BG <54 mg/dl lasting >15 minutes were also recorded. Overall, hypoglycemia was detected in 28 (40.6%) patients, including five treated with OHA only. T hypo ranged from 1 to 15% (6.1±4.7%), and was twice as long in insulin treated individuals than in those on OHA only (8.8±5.1 vs. 4.2±3.6; p<0.05). 57% of all patients experiencing hypoglycemia (including two treated with OHA only) had at least one episode of nocturnal CSH, with BG as low as 40 mg/dl, and none was symptomatic. To assess the relationship between hypoglycemia risk and degree of metabolic control the study subjects were divided into two subgroups: with good (n=29; HbA1c 7.2±0.6, range 6-8%) and poor (n=40; HbA1c 9.6±0.8, range 9-12%) metabolic control. Hypoglycemia was recorded in 37.9 and 42.5%, nocturnal hypoglycemia - in 54.5 and 58.8% of subjects from each group, and T hypo was 6.7±4.9 and 5.7±4.6%, respectively (p>0.05).
In conclusion, 40% of type 2 diabetes individuals experience hypoglycemia when assessed with CGMS for 5-6 days, with majority having asymptomatic nighttime events. Importantly, the high prevalence of CGMS detected hypoglycemia was not related to the degree of metabolic control of diabetes.
E. Szymanska-Garbacz: None. A. Borkowska: None. L. Czupryniak: None.