Living a healthy, happy life with Type 1 diabetes is, for the roughly 400,000 people who live with the condition in the UK, a delicate balancing act. Managing their blood glucose effectively means doing so with the highest possible level of accuracy and precision; people with Type 1 diabetes need to know how what they’re eating and what they’re doing is affecting their body at any given time to make the right decisions about the treatment they apply.
The consequences of an inaccurate blood glucose reading – and subsequently, the wrong dosage of insulin – can be deadly, and so ensuring people with diabetes only use SMBG devices of a certain standard is essential. Breton and Kovatchev demonstrated the correlation between meter accuracy and the potential of missed hypoglycaemic events, showing that at a meter accuracy of ± 20% that there was the possibility to miss 10 in 100 hypoglycaemic events. This reduced to 4 in 100 at meter accuracy of ± 15% and this was further reduced down to the possibility of missing just 1 in 100 hypoglycaemic events when the meter had an accuracy of ± 10%.
The reduced probability of these missed hypoglycaemic events due to improved meter accuracy can have a real impact in helping towards the overall costs associated with diabetes management due to emergency admissions and improved HbA1c.
The required standard has for a number of years been established by the ISO (International Organization for Standardization), and forms the basis of the regulatory requirements for FDA (Federal Drug Administration) and CE (Conformité Européenne) approval.
In order for the results of any measurement system to meet this standard and be deemed ‘reliable’, the analytical system has to meet the required performance standards. The operator, whether that’s a laboratory professional, any other health care professional or the person with diabetes, must also be competent and properly trained; practical skills like storing the test strips correctly, for example, are essential.
Measurement systems have quickly evolved in recent years, incorporating ever more sophisticated digital technology to increase their capabilities. Devices were once capable only of displaying a basic blood glucose reading. Now they can store those results, identify and provide a graphical record of trends over days, weeks and months, alert the device users when the results fall outside of pre-defined limits, and advise on the best course of action based on those results.
While this level of sophistication (and accompanying cost) may not be necessary for everybody with Type 1 diabetes, the same level of analytical performance is required regardless of the device’s versatility. As such, only one set of analytical standards are recognised globally: ISO 15197: 2013, a set of guidelines by the International Standards Organisation which stipulate 95% of blood glucose results should be within ± 0.83 mmol/L of laboratory results at concentrations of under 5.6 mmol/L and within ± 15% of laboratory results at concentrations of 5.6 mmol/L or more.
The regulatory requirements are clear. What isn’t clear is how many of the devices currently in use in the UK actually meet these requirements. Independent research has found that of all glucose monitoring strips currently prescribed by NHS England, for example, just 12.5% have been independently verified as meeting ISO 15197:2013 standards.
Device manufacturers are not in contravention of the rules in this respect; independent verification simply isn’t required. Instead, manufacturers need only meet the “Essential Requirements” of the applicable directives to obtain a CE mark, widely viewed as a guarantee of quality but in reality, obtainable by simply choosing and paying one “notified body” (NB) to analyse data provided by the manufacturer themselves, with no further scrutiny.
NBs vary widely in terms of quality across Europe and, importantly, are in direct competition with each other for the device manufacturers’ business. They typically have little if any knowledge about diabetes care, diabetes treatment, or in fact how a device which is being inspected will be used by a member of the public. The disastrous events in relations to hip implants and PIP breast implants have demonstrated the inefficiency of the system.” (EASD Press Release, March 14, 2013, Appendix 1)
As a result, a CE mark cannot be considered a valid assurance of accuracy in SMBG devices.
This raises concerns about the resulting quality of diabetes management achieved by users of some SMBG devices in the UK – and their consequent risk of avoidable complications from their diabetes. It has been shown in both simulation studies and in real world observation data that inaccurate glucose results are associated with poorer glycaemic control, e.g., higher HbA1c levels. As one author observed, this can also have “…implications for patient confidence in their day-to-day monitoring experience”.
This means, ultimately, that:
(i) the method for gaining regulatory approval in Europe, namely CE marking, is not fit for purpose. The current approach to regulation is based on performance data which may not be reliable.
(ii) there is a responsibility of the part of the purchaser [organisation] to independently verify the performance of the device prior to procurement or recommendation.
As newer blood glucose monitoring systems become available, tighter regulatory criteria must be urgently developed and put into routine practice – especially in the case where the measurements are made on alternative fluids to blood, such as interstitial fluid. The consequences of inaction, as increasing numbers of people with diabetes adopt more sophisticated SMBG technology, may be yet to be seen.
Meet the author Professor Christopher Price on our Advisory Group page.