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.

Trial registration: ClinicalTrials.gov NCT00081328.

© 2019 by the American Diabetes Association.

Figures

Figure 1

Adherence (≥80%) to SMBG and study medications (metformin ± rosiglitazone) over the first 2 years of TODAY.

Figure 2

Median SMBG% 24 months before and after insulin initiation for participants performing SMBG at least once daily and at least twice daily. Month 0 is the time the participant reached PO and initiated insulin therapy.

Figure 3

HbA1c (mean ± SE) 24 months before and after insulin initiation among SMBG% ≥80% vs. <80% for participants performing SMBG at least once daily (A) and at least twice daily (B). Month 0 is the time the participant reached PO and initiated insulin therapy.