The Effect of Cognitive Behavioral Therapy for Insomnia on Type 2 Diabetes Health Outcomes

Insomnia is a common sleep disorder, with three main symptoms: difficulty in initiating
sleep, difficulty in maintaining sleep, and/or waking up early without ability to return to
sleep. Insomnia can contribute to metabolic dysfunction, which can lead to type 2 diabetes
(T2D). Diabetes self-care behavior (DSCB) is important in attaining and maintaining glycemic
control, which worsens as a result of fatigue. People with insomnia usually suffer from
fatigue, which negatively influences quality of life. However, the additive effect of
insomnia symptoms on diabetes outcomes and health status in people with T2D is unknown.
Therefore, it is imperative to investigate the contributing factor that affects DSCB and
health outcomes to help individuals with diabetes reach their goals.

Assessing sleep variability is very important clinically and practically for people with
insomnia. People with insomnia have higher night to night sleep variability compared to
healthy individuals. Compared to other populations, people with T2D might suffer from sleep
disturbances due to diabetes symptoms such as frequency nocturnal urination, hyperglycemia,
insulin resistance, obesity, pain and fatigue, which might influence the sleep variability.
The nature of insomnia is not representable by using mean values, as the reduction in the
sleep variability values is a predictor for insomnia and depression recovery. Therefore,
understanding the sleep variability in people with T2D with or without insomnia symptoms may
add complementary evidence for future studies.

An effective treatment for people with insomnia is Cognitive Behavioral Therapy for Insomnia
(CBT-I). CBT-I is superior to sleep medications in terms of cost and long term benefits.
Although there is currently limited evidence about the effect of CBT-I on people with T2D,
CBT-I is a potentially effective intervention given insomnia's relationship with glucose
metabolism. The overall purpose of this study is to investigate the impact of both insomnia
symptoms and CBT-I on people with T2D. The central hypotheses are that people with T2D and
insomnia symptoms will have worse sleep, diabetes measures and self-reported outcomes
compared to people with T2D only, which might be adjusted with CBT-I.

Inclusion Criteria:

- Age between 40 to 75 years

- Self-reported diagnosis of type 2 diabetes

- Insomnia Severity Index >10 and self-reported symptoms of insomnia at least 3
nights/week for the past 3 months for insomnia and type 2 diabetes group

- Insomnia Severity Index ≤10 for type 2 diabetes only group

- Able to attend 6 sessions

- Able to understand and follow verbal commands in English

- Able to travel to our lab

Exclusion Criteria:

- Self-reported neurological diseases (e.g. Alzheimer's disease, Parkinson's disease,
Traumatic Brain Injury, Stroke, Multiple Sclerosis)

- Stop-Bang > 4 indicating severe risk of sleep apnea

- Failure to pass Restless Leg Syndrome Diagnostic Index

- Severe pain ≥ 7 out of 10 on Brief Pain Inventory

- Severe symptom level of depression scores ≥ 21 on Beck Depression Inventory

- Severe symptom level of anxiety scores ≥ 15 on Generalized Anxiety Scale-7

- Pregnant women

- Self-reported following medical issues: Chronic Fatigue Syndrome, Fibromyalgia, and
Rheumatic Diseases

- Speech deficits or significant auditory impairment

- Night-shift work

- Self-reported Bipolar and Seizure Disorders

- Heavy alcohol drinker (≥15 drinks per week for men and ≥ 8 drinks per week for women)

- Dialysis/blindness/trans-femoral amputation