Nighttime hypoglycemia under diagnosed in elderly with insulin-treated type 2 diabetes

The researchers suggest continuous glucose monitoring (CGM) as a promising tool for better-identifying hypoglycemia and adapting diabetes management in this population. CGM should be considered, especially in patients with risk factors such as cognitive impairment. 

"Hypoglycemia prevention is one of the major challenges for managing the elderly with insulin-treated T2D patients because hypoglycemia is linked with long-term complications and reduced quality of life," the researchers wrote. "Nocturnal hypoglycemia is common and rarely diagnosed by self-monitoring of capillary glucose tests as many of these episodes do not awaken the affected person."

In contrast to HbA1C, CGM appears to be a powerful tool to detect a nocturnal time in hypoglycemia and personalize patients' management, especially for those with cognitive impairment.

Considering the lack of real-life data on the frequency and predictive factors of hypoglycemia in older people with type 2 diabetes, Anne-Sophie Boureau and colleagues from France aimed to determine the predictors and frequency of hypoglycemia in older patients with insulin-treated T2D.

The prospective multicenter study comprised 155 type 2 diabetes patients treated with insulin (aged 75 years and older) with ≥2 self-monitoring of blood glucose (SMBG) daily controls. Patients underwent a diabetic and geriatric assessment and received ambulatory blinded CGM for 28 consecutive days with a FreeStyle Libre Pro sensor.

The study population of 141 has >70% CGM active time. Factors associated with SMBG confirmed hypoglycemia (≥70 mg/dL) and with nocturnal level 2 time below range (glucose concentration <54 mg/dL during ≥15 consecutive min between 0.00 and 6.00 am) were identified.

The authors reported the following findings:

• The mean age of the 141 analyzed patients was 81.5 ± 5.3 years, and 56.7% were male.
• The mean baseline HbA1c was 7.9% ± 1.0%. After a geriatric assessment, 102 participants were considered as complex and 39 as healthy.
• The primary endpoint (confirmed SMBG <70 mg/dL) occurred in 37.6% of patients.
• In multivariable analysis, the risk of SMBG-confirmed hypoglycemia was positively associated with a longer diabetes duration (OR (+1 year) =1.04) and glycemic variability evaluated by CGM (CV %) (OR (+1%) = 1.12).
• 65.2% of patients experienced nocturnal time in hypoglycemia (i.e., <54 mg/dL during ≥15 consecutive min between midnight and 6 am).
• In multivariable analyses, heart failure (OR: 4.81), cognitive impairment (OR: 9.31), and depressive disorder (OR: 0.19) were associated with nocturnal time in hypoglycemia.

The study reports a high hypoglycemia prevalence in older patients with insulin-treated type 2 diabetes, despite an HbA1c at baseline in the recommended range.

During the study period of 28 days, a third of patients experienced hypoglycemia based on SMBG, and two-thirds experienced TBR >15 min during night-time, independently of frailty and senior status. Risk factors of nocturnal TBR were heart failure, cognitive impairment, and an SMBG < 70 mg/dL during the day.

"Therefore, new tools in addition to HbA1c are needed for this population to reduce hypoglycemic events and TBR," the authors conclude. "Future randomized studies should further confirm the clinical benefit and modalities of CGM-derived parameters in older type 2 diabetes patients."

Reference:

Boureau, S., Guyomarch, B., Gourdy, P., Allix, I., Annweiler, C., Cervantes, N., Chapelet, G., Delabrière, I., Guyonnet, S., Litke, R., Paccalin, M., Penfornis, A., Saulnier, J., Wargny, M., Hadjadj, S., & Cariou, B. Nocturnal hypoglycemia is underdiagnosed in older people with insulin-treated type 2 diabetes: The HYPOAGE observational study. Journal of the American Geriatrics Society. https://doi.org/10.1111/jgs.18341