Abstract
Background: Type 1 diabetes mellitus (T1DM) is a chronic autoimmune disease. Glycaemic control is fundamental to management and involves frequent glucose monitoring, often using self-monitored blood glucose (SMBG) which carries considerable day-to-day burden. The use of flash glucose monitoring (FGM) systems as an alternative to SMBG is increasing. Literature is emerging regarding FGM associated-cutaneous adverse events (AEs). However, few studies have compared cutaneous AEs between FGM and SMBG and no studies have been conducted in youth with high-risk glycaemic control. Premature sensor loss is an additional issue associated with FGM use, of which existing literature is also limited. Thus, further research is required to investigate these issues and inform potential mitigating measures to improve user experience.
Aims: There were three broad aims: 1) to evaluate frequency and characteristics of FGM associated-cutaneous AEs, with comparison to SMBG; 2) to evaluate premature FGM sensor loss; and 3) to evaluate the effectiveness of an additional adhesive patch to prolong FGM sensor life.
Methods: Study 1 took advantage of adverse event and sensor loss data from a randomised controlled trial (RCT) among youth aged 13-20 years with T1DM and high-risk glycaemic control, in which participants were randomised to six-months of FGM use (intervention) or SMBG (control). Participants who completed the RCT were offered inclusion into Study 2, a crossover trial in which all participants received FGM. For Study 2, participants were allocated to receive a supplementary adhesive patch (intervention) or no additional adhesive (control) for three-months before crossing over into the opposite study arm. For both studies, all participants self-reported any cutaneous AEs fortnightly via an electronic questionnaire. Participants receiving FGM additionally reported any premature sensor loss and, for Study 2, any patch use to determine adherence to study protocol.
Results: Sixty-four individuals participated in Study 1 with a mean HbA1c (± standard deviation) of 96 (± 18) mmol/mol. Of completed questionnaires, 11% [40/362] from FGM participants and 11% [40/366] from SMBG participants reported a cutaneous AE (P=0.96). With regards to severity, 80.0% [32/40] of FGM and 82.5% [33/40] of SMBG cutaneous AEs were rated as mild (P=1.00). Only one participant ceased using FGM due to recurring cutaneous AEs. In Study 1, 24% [87/362] of questionnaires reported premature sensor loss, predominantly due to issues with the sensor adhesion. Only 3% [3/87] were related to a cutaneous AE. Thirty-four participants enrolled in Study 2. Premature sensor loss was reported in 20% [32/162] of questionnaires from the intervention (additional adhesive patch) and 17% [26/152] from control (P=0.56). The per protocol analysis of intervention compliant questionnaires [196/314] showed similar findings (P=0.38). Additionally, there was no significant difference between cutaneous AEs among use or non-use of the adhesive patch (6% [5/78] and 3% [3/118], respectively, P=0.27).
Conclusions: Among youth with T1DM and high-risk glycaemic control, cutaneous AEs associated with FGM use were common, mostly rated mild, and occurred at a similar perceived rate and severity comparative to SMBG. Premature FGM sensor loss was also commonly experienced among this cohort, however the use of an additional adhesive patch did not appear to significantly prevent this, nor cause additional AEs. Thus, awareness and further investigation of these issues and the effectiveness of other prevention or mitigation measures are vital to T1DM care.