Wearing your Way to Safety Critical Roles
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'Wearables have a clear potential for opening safety critical roles. The time has maybe come for a renewed industry position on diabetes, as well as for new guidance on the use of wearable monitoring devices to manage specific medical conditions'. - Rishi Parwani and Brandon Limonard, Research Analysts

Wearables and the monitoring of medical conditions

Wearable technology can provide users with a lot of live information about their health status, and as such, help people to manage their lifestyle and healthcare. Wearables can even save lives in certain circumstances: cases have been reported in which people were able to get timely emergency medical care thanks to the alerts their wearable devices provided. Wearables are becoming part of the daily management of medical conditions such as diabetes, and have the potential to help open up access to jobs when the risks associated with the condition are sufficiently reduced.

The case of diabetes

We choose in this article to look at the benefits of wearables for the management of diabetes, as it is estimated that there are 4.6 million people affected by this condition in the UK.

On the one hand, people with diabetes are protected against discrimination at work as it is classed as an ‘unseen disability’ under the Equality Act (2010), so employers should make reasonable adjustments to support diabetic job applicants and employees.

On the other hand, some types of diabetes may be seen as incompatible with the special requirements of safety critical roles, as hypoglycaemia, which is often a side effect of insulin-based treatment, can lead to impaired concentration, confusion, and even loss of consciousness.

In the case of rail, Regulation 24 of the Railways and Other Guided Transport Systems requires the controller of safety critical work to ensure that their staff are competent and fit to undertake their safety critical activities, and the Train Driver License Certificate Regulation (TDLCR) includes general requirements in relation to medical fitness and specifically states that:

'Drivers must not be suffering from any medical conditions or be taking any medication, drugs or substances that are likely to cause:

  • A sudden loss of consciousness,
  • A reduction in attention or concentration
  • sudden incapacity
  • A loss of balance or co-ordination, or significant limitation of mobility."

Where wearables can help

Advances in wearable technology have enabled the development of Continuous Glucose Monitoring (CGM) systems, transforming the lives of patients by allowing them to non-invasively monitor and forecast their blood glucose levels in real-time, and sending alerts when levels drop dangerously low (hypoglycaemia occurs when blood sugar levels drop below 70mg/dL).

CGMs allow people to adjust their insulin levels through injections at the right moment to keep blood glucose within a safe range. They offer better protection against extreme level swings, which are the triggers of disorientation or loss of consciousness events, than sampling of blood from fingertips.

Current CGMs

Dexcom’s CGM system

Dexcom’s CGM system is one the first non-invasive glucose monitoring wearables that does not require a finger prick blood test for calibration. On average, people with type 1 diabetes will have over 65,000 insulin injections over the course of their lifetime however the introduction of wearable technology dynamically changes individual monitoring requirements. Dexcom’s system enables real-time monitoring of blood glucose levels via a small, resistant sensor which measures glucose levels beneath the skin. This data can then be viewed on a smartphone app and the system can also send alerts when blood sugar levels are too high or low. Dexcom’s G5 is worn on the upper abdomen and is primarily used for patients with type 1 diabetes, or who intensively manage their diabetes with insulin. Its readings let people make treatment decisions from the information, for instance choosing between eating carbohydrates or taking insulin.

MiniMed 670G system

Dexcom's G5 is currently only approved by the United States Food and Drug Association for abdominal use, but suppliers such as PKVitality are developing smartwatches with the same functionality (K'Track Glucose).

Some wearables offer the dual function of monitoring glucose levels, and automatically administering insulin based on the sensor glucose values. For example, MiniMed's 670G system is a combination of a CGM device and an insulin pump, that automatically maintains good glucose control by mimicking the functions of a healthy pancreas, providing protection against hypoglycemia. The system automatically detects and stops administration of insulin 30 minutes in advance when blood glucose levels are approaching pre-set limits.

In a not too far-off future, the insulin pumps could be replaced by ultra-light insulin patches relying on chemical rather than mechanical injection. Research is however still at an early stage in this domain.

Ongoing research

Wearable glucose sensor

Miniaturisation and non-invasiveness are the key parameters steering research on alternative glucose monitoring systems. Several university labs have reported progress in developing skin-worn flexible devices that monitor blood glucose using electrochemical sensors. The sensors being trialled include small meters strapped to the arm, skin patches, and tattoos, and can transmit data wirelessly to handheld devices.

GPhone, an innovative glucose monitoring system using in the proof-of-concept stage, enables real-time monitoring through the use of a smartphone case that comes equipped with a sensor. Enzyme-packed pellets magnetically attach to the sensor and once a sample of blood is dropped on the pellets, the glucose levels can be measured.

Google (Alphabet)’s Verily and pharmaceutical company Novartis have partnered to develop a new CGM system that can monitor glucose levels through contact lenses . The technology, which is still in early development, will incorporate sensors that can non-invasively track the user’s blood sugar levels through their basal tears.

Other researchers are exploring how skin patches can use the glucose levels in sweat as an indicator of overall blood glucose concentration.

Disposable wearable patch

A team at Seoul National University in South Korea has found a way to read glucose levels in skin sweat with a disposable wearable patch. The sweat contains a small amount of glucose which is derived from blood and interstitial fluid. Because the concentration of glucose in sweat is much lower than that in the blood, the team built highly sensitive sensors but they acknowledge more work needs to be done to refine the technology to the point they can match the accuracy of a direct reading of interstitial fluid or blood.

Considerable challenges lie between the current state of research and the commercialization of reliable and robust continuous monitoring devices. The most crucial of these is to establish a correlation between what the sensors detect and the real blood glucose concentrations. Further research is also needed to account for the effect of different levels of exercise and differences due to the location of the sensors.

What next?

Although the development of surface skin-based glucose monitors is only just beginning, current CGM systems have already proven their accuracy and usefulness.

The Secretary of State for Transport’s Honorary Medical Advisory Panel on Driving and Diabetes Mellitus recently (April 2018) recognised in its published meeting minutes:

'From the evidence supplied the panel was satisfied that these systems, significantly decrease the risk of hypoglycaemic episodes in users. The panel recognised that this is a rapidly developing area, and it is likely that many systems will be available over the coming years.'

This follows changes in regulations made by both the Civil Aviation Authority (CAA) and the Driving Vehicle Licence Agency (DVLA) regarding diabetic pilots and drivers. The CAA introduced both commercial and unrestricted private flying for pilots with insulin-treated diabetes in 2012 and published updated policies and recommendations for pilots with diabetes in 2015. The DVLA amended the Motor Vehicles Driving Licence Regulations in 2018, to reflect the positive advances in CGM technology.

If aviation and road transport have both come to consider that diabetes can now be effectively managed through the appropriate use of monitoring wearables, where does this leave rail?
There is a clear potential for opening safety critical roles for individuals monitoring and managing robustly their diabetic condition, without increasing risk. The time has maybe come for a renewed industry position on diabetes, as well as for new guidance on the use of wearable monitoring devices to manage specific medical conditions.

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