Authors: (including presenting author): :
Young HKB(1), Kwok CYI(2), Hui PSG(1), Yan KS(1), Wong YSF(1), Wong MC(1), Cheung
TK(2)
Affiliation: :
(1)Department of Medicine & Rehabilitation, Tung Wah Eastern Hospital, (2)Department
of Clinical Psychology, Tung Wah Eastern Hospital
Keyword 6: :
Glycemic variability
Introduction: :
Glycemic variability (GV) independently predicts diabetic complications, with fluctuations promoting oxidative stress, inflammation, and endothelial dysfunction. Insomnia and obstructive sleep apnea (OSA) are highly prevalent in Type 2 Diabetes (T2D) and may exacerbate metabolic dysregulation, but their impact on nocturnal GV in treated patients with apparently stable glycemic control remains unclear.
Objectives: :
This study evaluated whether insomnia, OSA, and their co-occurrence (COMISA) have distinct nocturnal GV profiles in a real-world cohort of well-controlled T2D.
Methodology: :
Fifty-nine patients with T2D (median age 62.0 years) underwent up to 15 consecutive nights of continuous glucose monitoring (CGM; Abbott Libre 2) paired with objective sleep assessment via Belun Ring (BR). Participants were classified as OSA (BR-AHI3% ≥15; N=19), insomnia (BR sleep efficiency < 80% with intake interview; N=11), or COMISA (meeting criteria for both disorders; N=29). Nocturnal GV was quantified using sleep-time coefficient of variation (SLP-CV) and sleep-time continuous overall net glycemic action (SLP-CONGA). Groups differences in median GV were tested, followed by generalized linear mixed-effects models (GLMMs) adjusted for age, sex, BMI, and HbA1c, incorporating participant-level random intercepts to account for night-to-night variability.
Result & Outcome: :
COMISA and insomnia exhibited higher SLP-CV (12.3% and 13.3%) than OSA (8.9%, both p< 0.05), despite comparable glycemic control across groups (median HbA1c 7.3 vs 7.2% vs 7.1% for COMISA, insomnia, and OSA; p=0.81; 83% on metformin; 19% on insulin). Males exhibited higher nocturnal GV than females for both SLP-CV (p=0.07) and SLP-CONGA (p< 0.05). In adjusted GLMMs, COMISA was associated with a 39% increase in nocturnal SLP-CV (β=0.33, p< 0.05) and insomnia with a 43% increase (β=0.36, p< 0.05) compared with OSA. Moreover, male sex (β=-0.24, p< 0.05) and a higher REM% (β< 0.01, p< 0.05) were independently associated with higher SLP-CV. This pioneering study identifies Insomnia and COMISA as independent drivers of elevated nocturnal GV in pharmacologically treated T2D, a metabolic risk factor linked to microvascular and macrovascular complications that is not reflected by HbA1c. Multi-night CGM integrated with sleep monitoring reveals hidden nocturnal metabolic instability, suggesting T2D patients with insomnia-related phenotypes and male sex, represent a high-risk subgroup who may benefit from personalized sleep and metabolic interventions.
