Continuous glucose monitors

02 May 2024
Volume 6 · Issue 5

Abstract

In this month's article, George Winter discusses the application of continuous glucose monitors – mobile telephony systems that facilitate recording of physiological measurements

The Department of Health and Social Care (DHSC, 2023) explains that under the NHS Constitution ‘you can make a significant contribution to your own, and your family's, good health and wellbeing, and take personal responsibility for it.’ And in a survey of Swedish GPs, Björk et al (2021) reported that being responsible for your health ‘may further mean that you own your health problem, take active measures to keep and improve your health, accept help in health and/or that you do not offload all responsibility onto your GP.’

A recent innovation enabling individuals to exercise responsibility for their own health is the application of mobile telephony systems that facilitate certain physiological measurements to be recorded and shared. For example, the British Heart Foundation (BHF, 2024) considers smartphone and wearable data to have ‘huge potential to contribute to cardiovascular research and healthcare’ and the BHF's Data Science Centre aims to establish a prospective, large-scale smartphone and wearable dataset linked with participants' NHS data. A survey of 194 health professionals and members of the public revealed a range of parameters they would be happy to share, with some suggestions from the public ‘for active data, including diet, alcohol use, blood glucose, free text comments and timing of medications’ (BHF, 2024).

‘The technological advances offered by continuous glucose monitors must be tested, evaluated, and demonstrated to be robust before being used outside clinical settings’

Especially interesting is the reference to blood glucose, given a recent BBC News report quoting NHS national diabetes advisor Professor Partha Kar, who asserts that while continuous glucose monitors (CGMs) are valuable aids for those with diabetes, using CGMs ‘when there's no health reason to do so can drive an obsessive focus on numbers’ (Schaer, 2024).

However, some might argue that an obsessive focus on numbers occurs when considering other physiological parameters like blood cholesterol concentrations. For example, both the NHS (2022) and Heart UK (2024) provide detailed advice on what they deem to be optimal concentrations of blood cholesterol. Yet substantial peer-reviewed evidence questions the dogma that implicates cholesterol as a cause of cardiovascular disease – see, for example, Mente et al (2017); Ravnskov et al (2018); and Schersten et al (2011).

Another aspect that deserves consideration in the context of making CGMs available beyond those patients with diabetes is that provided by Cucuzzella et al (2021). These authors note that since we are now ‘witnessing remission of type 2 diabetes (T2D) through nutritional interventions specifically low carbohydrate diets (LCDs), we must apply the same effort and thought to de-prescribing as the underlying metabolic condition improves’ (Cucuzzella et al, 2021).

One might infer that the growing evidence base on the effectiveness of LCDs in driving T2D remission means that the evolution of a primarily nutritional – as opposed to a medication-focused – approach would be strengthened if apparently healthy individuals had the opportunity to use CGMs and learn through education and direct experience about the relationship between food consumption and the concentration of glucose released consequently.

Indeed, Childers (2023) notes that while hyperglycaemia occurs in diabetics, ‘a 2018 Stanford CGM study found hyperglycaemia to occur in healthy subjects as well’, and contrary to the researchers' expectations ‘80% of healthy subjects showed prediabetic or diabetic-like glucose spikes after eating unsweetened cornflakes and milk.’ Childers (2023) further observes that 80% of healthy subjects would not have been expected to exhibit insulin resistance.

And when Khan et al (2022) evaluated the effect of CGM use among 57 individuals with prediabetes, they hypothesised that after three months those using CGMs combined with diabetes education would show improved adherence to lifestyle modifications and greater reduction of HbA1c compared to those receiving diabetes education alone. They found that ‘CGM use in addition to diabetes education resulted in improvement in physical activity, food choices, HbA1c, weight, and blood pressure in individuals with prediabetes’ (Khan et al, 2022).

The technological advances offered by CGMs must be tested, evaluated, and demonstrated to be robust before being used outside clinical settings. However, given the progress being made in harnessing mobile telephony to healthcare it can be argued that if individuals are expected to take responsibility for their own health, they should be trusted to access support, education, and instruction to discover how they can best avoid being at risk from T2D and its unpleasant outcomes.

It should not always be assumed that some concepts are too difficult for the public to grasp.