Effectiveness of continuous glucose monitoring in maintaining glycaemic control among people with type 1 diabetes mellitus: a systematic review of randomised controlled trials and meta-analysis

Abstract

Aims/hypothesis The aim of this work was to assess the effectiveness of continuous glucose monitoring (CGM) vs selfmonitoring of blood glucose (SMBG) in maintaining glycaemic control among people with type 1 diabetes mellitus. Methods Cochrane Library, PubMed, Embase, CINAHL, Scopus, trial registries and grey literature were searched from 9 June 2011 until 22 December 2020 for RCTs comparing CGM intervention against SMBG control among the non-pregnant individuals with type 1 diabetes mellitus of all ages and both sexes on multiple daily injections or continuous subcutaneous insulin infusion with HbA 1c levels, severe hypoglycaemia and diabetic ketoacidosis (DKA) as outcomes. Studies also included any individual or caregiver-led CGM systems. Studies involving GlucoWatch were excluded. Risk of bias was appraised with Cochrane risk of bias tool. Metaanalysis and meta-regression were performed using Review Manager software and R software, respectively. Heterogeneity was evaluated using χ 2 and I 2 statistics. Overall effects and certainty of evidence were evaluated using Z statistic and GRADE (Grading of Recommendations, Assessment, Development and Evaluation) software. Results Twenty-two studies, involving 2188 individuals with type 1 diabetes, were identified. Most studies had low risk of bias. Meta-analysis of 21 studies involving 2149 individuals revealed that CGM significantly decreased HbA 1c levels compared with SMBG (mean difference −2.46 mmol/mol [−0.23%] [95% CI −3.83, −1.08], Z = 3.50, p=0.0005), with larger effects experienced among higher baseline HbA 1c >64 mmol/mol (>8%) individuals (mean difference −4.67 mmol/mol [−0.43%] [95% CI −6.04, −3.30], Z = 6.69, p<0.00001). However, CGM had no influence on the number of severe hypoglycaemia (p=0.13) and DKA events (p=0.88). Certainty of evidence was moderate. Conclusions/interpretation CGM is superior to SMBG in improving glycaemic control among individuals with type 1 diabetes in the community, especially in those with uncontrolled glycaemia. Individuals with type 1 diabetes with HbA 1c >64 mmol/mol (>8%) are most likely to benefit from CGM. Current findings could not confer a concrete conclusion on the effectiveness of CGM on DKA outcome as DKA incidences were rare. Current evidence is also limited to outpatient settings. Future research should evaluate the accuracy of CGM and the effectiveness of CGM across different age groups and insulin regimens as these remain unclear in this paper. PROSPERO registration Registration no. CRD42020207042.

Effect of Different Glucose Monitoring Methods on Bold Glucose Control: A Systematic Review and Meta-Analysis

“…Reducing HbA1c levels can effectively reduce the incidence of cardiovascular disease and death [ 26 ]. Compared with the SMBG group, the risk of severe hypoglycemic events in the CGM group was reduced by 48%, which is inconsistent with the results of other meta-analyses [ 6 , 27 ]. This difference may be related to inconsistent criteria for determining adverse events.…”

“…Insulin treatment can effectively decrease blood sugar. Monitoring blood glucose levels is also very important to keep the blood glucose level at a normal level [ 5 , 6 ].…”

Continuous glucose monitoring and hypoglycaemia events: unmet needs. Reply to Papaioannou TG, Snoudou D and Tsiofis C [letter]

“…As mentioned in our study, subgroup analyses stratified according to the various CGM systems were conducted and the analyses reported no significant subgroup difference (p=0.88) (ESM Fig. 4 in our original paper [2]). In other words, the difference in CGM systems is not a significant covariate to the effectiveness of CGM in maintaining glycaemic control compared with selfmonitoring of blood glucose (SMBG).…”

“…To the Editor: I would like to thank Papaioannou et al [1] for highlighting some technological and clinical issues that could help with the interpretation of the results from our study [2]. They mention that the technological differences between the continuous glucose monitoring (CGM) systems (i.e.…”

“…Papaioannou et al also mention the self-monitoring frequency of flash glucose monitoring in relation to glycaemic control [1]. As the subgroup analysis revealed no significant subgroup difference, we prioritised explaining the rationale behind the significant results instead [2]. Notably, self-monitoring frequency itself is a valuable factor that future studies could investigate.…”