Self-Monitoring of Blood Glucose in Youth-Onset Type 2 Diabetes: Results From the TODAY Study

Abstract

OBJECTIVE To determine whether self-monitoring of blood glucose (SMBG) is associated with lower HbA1c in youth with type 2 diabetes taking oral medications only or after starting insulin for persistently elevated HbA1c. RESEARCH DESIGN AND METHODS Treatment Options for Type 2 Diabetes in Adolescents and Youth (TODAY) study participants (n = 699) taking oral medications were asked to perform SMBG twice daily. After reaching primary outcome (PO) (HbA1c ≥8% [64 mmol/mol]) over 6 months or an inability to wean from temporary insulin because of metabolic decompensation), insulin glargine was started. HbA1c and percent of SMBG (SMBG%) (percent days when the meter was used one or more times) before and after PO were analyzed. RESULTS SMBG declined over time and was inversely related to HbA1c (P < 0.0001). Of 298 youth who reached PO and started insulin, 282 had SMBG data. At PO, mean ± SD age was 15.8 ± 2.3 years, BMI 35.5 ± 7.9 kg/m2, and HbA1c 9.6 ± 2.0% (81 ± 21.9 mmol/mol); 65.3% were female. Median SMBG% was 40% at PO, which increased to 49% after 6 months and fell to 41% after 1 year on insulin. At PO, 22% of youth checked ≥80% of days, which increased to 25% and fell to 19% after 6 and 12 months using insulin, respectively. At PO, compared with those who checked <80%, youth who checked ≥80% were younger and with a lower BMI, HbA1c, and blood pressure. SMBG ≥80% was associated with ≥1% reduction in HbA1c at 6 and 12 months after insulin initiation. CONCLUSIONS Low SMBG adherence was common and associated with higher HbA1c. Optimal SMBG frequency in youth using or not using insulin, and whether less frequent SMBG is a marker for overall worse self-care, require further study.