New insights from continuous glucose monitoring into the route to diabetes.
AIM
Type 2 diabetes mellitus (T2DM) is preceded by a period of impaired glucoregulation. We investigated if continuous glucose monitoring system (CGMS) (1) could improve our capacity to predict the development of T2DM in subjects at risk. (2) Find out if impaired fasting glucose/impaired glucose tolerance differentiation through CGMS would also elucidate differences in clinical phenotypes.


MATERIAL AND METHODS
Observational study of 209 hypertensive patients, aged 18 to 85 years who wore at entry a CGMS. Two CGMS metrics, percent of time under the 100 mg/dL glycaemic threshold (TU100) (impaired fasting glucose surrogate phenotype) and area above the 140 mg/dL glycemic threshold (AO140) (impaired glucose tolerance surrogate phenotype) were measured. The median follow-up was 32 months (6-72 mo), and there were 17 new cases of T2DM.


RESULTS
In a multivariate Cox proportional hazard survival analysis including the conventional prediabetes-defining criteria and the 2 CGMS-derived variables, only TU100 and HbA1c were significant and independent variables in predicting T2DM development. An increase in 0.1 in TU100 resulted in a 0.69 (95% CI, 0.54-0.88; P < .01) odds ratio of developing T2DM. With cut-off points of 0.5 for TU100 and 5.7% for HbA1c , the test "TU < 0.5 and HbA1c  > 5.7%" had a sensitivity of 0.81 (SD, 0.10), a specificity of 0.83 (SD, 0.03), and a likelihood ratio of 4.82 (SD, 1.03) for T2DM development.


CONCLUSIONS
Continuous glucose monitoring system allows for a better T2DM risk-development categorization than fasting glucose and HbA1c in a high-risk population. Continuous glucose monitoring system-derived phenotyping reveals clinical differences, not disclosed by conventional fasting plasma glucose/HbA1c categorization. These differences may correlate with distinct pathophysiological mechanisms.
['Colas|Ana|A|', 'Vigil|Luis|L|0000-0001-7484-2911', 'Rodríguez de Castro|Carmen|C|', 'Vargas|Borja|B|', 'Varela|Manuel|M|']
D000293:Adolescent D000328:Adult D000368:Aged D000369:Aged, 80 and over D015415:Biomarkers D001786:Blood Glucose D015190:Blood Glucose Self-Monitoring D003924:Diabetes Mellitus, Type 2 D005260:Female D005500:Follow-Up Studies D018149:Glucose Intolerance D006801:Humans D006973:Hypertension D008297:Male D008875:Middle Aged D011236:Prediabetic State D011379:Prognosis D015996:Survival Rate D055815:Young Adult
continuous glucose monitoring system impaired fasting glucose impaired glucose tolerance diabetes risk development