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. flash glucose monitoring and real-time CGM) could explain the reason behind the conflicting evidence. 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 self-monitoring of blood glucose (SMBG). 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. However, among the 22 studies included in our manuscript, only two studies used flash glucose monitoring; the majority of studies did not report/measure participants’ self-monitoring frequency of CGM [2]. This prevented any meaningful comparison from being made and therefore, aligns with the suggestion by Papaioannou et al: for future research to shed light on participants’ compliance with CGM.

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The author declares that there are no relationships or activities that might bias, or be perceived to bias, their work.

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The author is the sole contributor to this paper.