Page 55 - Glucose Monitoring Devices

Quantifying the effect of inaccurate BGM systems 53

Quantifying the effect of inaccurate BGM systems
In this discussion, we focus on SMBG using BGM systems that provide a single
estimate of plasma glucose using a direct capillary blood measurement. Although
a patient can opt instead for a flash glucose monitor (FGM) device or a continuous
glucose monitor (CGM) [15], BGM systems are still prevalent in the market and will
be for years to come, particularly if we focus on type 2 diabetes. In many underde-
veloped countries, the BGM system technology is the only option for patients
[7,16,17]. Furthermore, understanding the effect of BGM system accuracy can be
directly applicable to FGM and to CGM devices requiring frequent calibration.
In the latter case, the accuracy characteristics of the BGM system used to calibrate
will spill over to the CGM device affecting its performance [18,19].
The analytical and clinical accuracy of glucose monitoring devices has been a
long-standing preoccupation of the community [1]. Separate efforts have developed
analytical [20e22] and clinical [23e25] methods, metrics, and visualization tools.
A plethora of BGM system accuracy assessments have become recently available
[8,10e14,26,27], some of these conducted after device approval [9]. As a result
of these efforts, many recommendations [28e33], and international standards
such as ISO 15197 in its 2003 and 2013 versions [34,34] have been produced.
Despite the abundance of information, the study of the relationship between
analytical and clinical accuracy and short- and long-term consequences for the
patient and the healthcare system is still in its infancy and represents a challenging
problem. The reasons for this are multiple and are worth discussing here.

A complex system

Fig. 4.2 represents a simplified system view of self-treatment. To illustrate this,
consider the case of severe hypoglycemia. A poor glucose BGM system reading
(technology) can lead to over bolus producing a severe hypoglycemia event [35]

Metabolism Behavior
glucose-insulin-glucagon meal-bolus-exercise

Environment
Technology
health care provider- meter/sensor-pump/pen
family-peers
FIGURE 4.2
The diabetes management system.