The occurrence of hypoglycemia is a well-known problem in the treatment of patients with diabetes mellitus (DM) type 1 (T1DM) and type 2 (T2DM), but little is known about hypoglycemia in elderly people without DM.
Older individuals with DM are at a notably higher risk for severe hypoglycemia due to age, duration of DM, duration of insulin therapy, and higher prevalence of hypoglycemia unawareness [1, 2]. Hypoglycemia is often underdiagnosed and can lead to several complications, such as falls, fall-related fractures, epileptic seizures, cognitive deficits, and persistent frailty [3, 4]. Also, the similarity between symptoms of hypoglycemia and symptoms of dementia, such as confusion, agitation and behavioural changes, may lead to missed diagnosis of hypoglycemic episodes in older people [5].
Prevention of hypoglycemia is especially important for elderly persons with long-lasting DM and associated complications, who are prone to asymptomatic hypoglycemia [6, 7]. HbA1c levels give an indication of the average glycemic value, but not of the glycemic variability. Appropriate treatment is essential using specific target values for metabolic control. Different target values for HbA1c for different age groups have been proposed [6, 8]. Hypoglycemia is associated with cognitive and functional decline in older people with diabetes. Identification of individuals at risk and prevention of hypoglycemia is therefore an important task in the management of diabetes in home-dwelling older people with diabetes [5].
It is well known that T2DM increases the risk for cognitive decline and dementia such as Alzheimer’s disease (AD) and vascular dementia [9, 10, 11]. It has been established that increased prevalence of hypoglycemia can worsen cognitive decline in T2DM patients.
Continuous Glucose Monitoring (CGM) can be used to measure hypoglycemia rate, duration and glycemic variability. Several devices for CGM are available: Dexcom (G4, G5 and G6), Medtronic (Guardian Connect and Guardian Sensor 3), Senseonics Eversense and Abbott (FreeStyle Libre and FreeStyle Libre 2). Safe and effective therapeutic decision-making can be facilitated by establishing target percentages of time in the various glycemic ranges, hoping to meet the specific needs of special diabetes populations. The primary goal for effective and safe glucose control is to increase the Time in Range (TIR), while reducing the Time Below target glucose Range (TBR). These CGM-based targets must be personalized if applied to individual DM patients [1].
Very little is known about the occurrence of hypoglycemia as part of the normal ageing process in non-diabetic elderly people and secondly, if the incidence of hypoglycemia is associated with cognitive decline. There is one report by Adolfsson et al. showing a lower fasting glucose in persons with AD [12]. In addition, it has been demonstrated that hypoglycemia occurs in non-DM hospitalized patients [13]. Blood glucose levels also need to be screened in other settings, and especially during common infections, also in nondiabetics, to identify persons at high risk for infection-related hypoglycemia (IRH). Arinzon et al. made a comparative study of diabetic and nondiabetic persons and IRH seems to indicate a poor general health status rather than being the cause of death [14].
Various physiological mechanisms are involved to prevent hypoglycemia: glucagon and norepinephrine play an important role in correcting hypoglycemia in normal human physiology. It could be possible that the impairment of the central sympathic autonomic nervous system negatively facilitates the occurrence of hypoglycemia [15].
If present, autonomic neuropathy in normal ageing could contribute to a higher risk of hypoglycemia and subsequently enhance cognitive decline. To our knowledge, no studies are available that have addressed this issue.
The aim of our study was to detect hypoglycemia in elderly non-DM people using CGM and to compare this to a DM control group.