The Impact of Cognitive Behavioral Therapy for Insomnia (CBT-I) on Glycemic Control in Older Type 2 Diabetes (T2D) Comorbid With Insomnia

Inclusion Criteria: 1. Aged ≥60 years; 2. T2D with suboptimal glycemic control defined as HbA1c 7.1-10%; 3. Chinese ethnicity; 4. Comorbid with insomnia having ISI score \>10; 5. Able and willing to give informed written consent Exclusion criteria: 1. Cognitive impairment (HK-MoCA score of ≤22); 2. Depression (GDS-15 score \>8) and other psychiatric disorders e.g. generalized anxiety disorder, restless leg syndrome, schizophrenia to be elucidated by history from research nurse and questionnaires; 3. Benign prostatic hypertrophy by history and/or elevated PSA and any other chronic medical condition that is likely to affect sleep e.g. chronic pain; 4. Concurrent use of hypnotic drugs, psychotic medications and any drugs that are known to affect sleep; 5. Cerebrovascular accidents, vascular dementia, or any condition that are known to affect cognitive function; 6. Shift workers; 7. Haemoglobinopathies, renal failure, need of regular blood transfusion or any other conditions which will affect the validity of HbA1c in measurement of glycemia; 8. Any condition, as judged by the investigators, as ineligible to participate in this study.