Endocrine Abstracts

Objective: Nation-wide reimbursement of intermittently scanned continuous glucose monitoring (isCGM) for people with type 1 diabetes was introduced in Belgium in 2016. We investigated whether diabetes knowledge and health literacy would impact glycemic control after one year of isCGM use.

Research design and methods: In this substudy of the FUTURE trial, a prospective observational real-world cohort study in individuals with type 1 diabetes ≥16 years old, we assessed diabetes knowledge using a new 10-item questionnaire (Patient Education And Knowledge [PEAK]) and health literacy using the validated 6-item Newest-Vital Sign-D (NVS-D) questionnaire. Primary outcome measure was the association between PEAK score and change in HbA1c. Secondary outcome measures were the association between the NVS-D score and change in HbA1c, the link between time spent in/above/below range and scores on the PEAK/NVS-D questionnaires.

Results: 851 subjects were consecutively recruited between July 2016 and July 2018. Median PEAK score was 8 (range: 0–10) and median NVS-D score was 6 (range 0–6). HbA1c improved from 7.9 [7.8; 8.0]%, 63 [62; 64] mmol/mol at start to 7.7 [7.6; 7.7]%, 61 [60; 61] mmol/mol (P < 0.001) at 6 months and to 7.8 [7.7; 7.9]%, 62 [61, 63] at 12 months (P < 0.001). Time spent < 70 mg/dl and < 54 mg/dl were reduced by respectively 15% (from 9.6 [9.1; 10.1]% to 8.2 [7.8; 8.7]%, P < 0.001) and 14% (from 4.2 [3.9; 4.5]% to 3.6 [3.4; 3.9]%, P < 0.001) after 12 months. Time spent > 180 mg/dl was increased during the study period by 6% after 12 months (from 37.7 [36.6; 38.9]% to 39.9 [38.7; 41.1]%, P < 0.001). HbA1c only improved in those with higher scores on PEAK score (PEAK score 7–8: from 8.0 [7.8; 8.2]%, 64 [62, 66] mmol/mol to 7.7 [7.5; 7.8]%, 61 [58, 62] mmol/mol at 12 months, P = 0.005; PEAK score 9–10: 7.9 [7.7; 8.1]%, 63 [61, 65] mmol/mol) to 7.7 [7.6; 7.8]%, 61 [60, 62] mmol/mol) at 12 months, P < 0.001) and NVS-D questionnaires (NVS-D score 4–6: 7.9 [7.8; 8.0]%, 63 [62, 64] mmol/mol) to 7.7 [7.6; 7.8]%, 61 [60, 62] mmol/mol) at 12 months, P < 0.001). Time spent > 180 mg/dl increased in those with the lowest score on the NVS-D questionnaire (from 38.4 [35.3; 41.5]% to 41.8 [38.4: 45.3]%, P = 0.042).

Conclusions: In this large cohort of well-educated adults with type 1 diabetes, use of isCGM resulted in an improvement in HbA1c and a reduction of time in hypoglycemia. However, HbA1c only improved in those with higher scores on the PEAK/NVS-D questionnaires, pointing towards the importance of diabetes knowledge and health literacy.