This prospective cross-sectional observational study aims to explore the relationships among psychological well-being, depression, and quality of life in patients with type 2 diabetes attending the outpatient metabolic clinic at National Taiwan University Hospital. The study will collect data using standardized instruments, including the EQ-5D Health-Related Quality of Life Questionnaire, the PHQ-9 Depression Scale, and the Shalom Scale of Psychological Well-Being, along with demographic and clinical variables such as age, sex, education, body mass index, HbA1c, disease duration, and psychosocial support indicators. Descriptive statistics, Pearson correlation analyses, ANOVA, and multiple linear regression modeling will be performed to identify factors associated with psychological well-being. The findings are expected to provide evidence-based insights to inform tailored interventions and improve the mental health and quality of life of patients with type 2 diabetes.

This is a prospective, cross-sectional observational study designed to examine the relationships among psychological well-being, depression, and quality of life in adult patients with type 2 diabetes attending the outpatient metabolic clinic at National Taiwan University Hospital. The study seeks to identify demographic, clinical, and psychosocial factors associated with psychological well-being in this population.

Eligible participants will be ≥18 years old, diagnosed with type 2 diabetes, able to complete self-administered Chinese questionnaires, and willing to provide written informed consent. Patients with major psychiatric disorders, moderate to severe cognitive impairment, acute diabetic complications, or significant communication barriers will be excluded.

Data collection will include demographic variables (e.g., age, sex, education, marital status, religious belief, economic status, family support, sleep quality, exercise habits) and clinical indicators (e.g., diabetes duration, BMI, HbA1c, diabetic complications, estimated glomerular filtration rate). Three standardized instruments will be administered:

EQ-5D-5L to measure health-related quality of life

PHQ-9 to assess depressive symptoms

Shalom Scale to evaluate psychological well-being

The planned sample size is 350 participants. Recruitment will be conducted by the research team during clinic hours. Written informed consent will be obtained before any data collection.

Statistical analyses will include descriptive statistics to summarize participant characteristics and scale scores, Pearson correlation analyses to examine associations between variables, one-way ANOVA to compare psychological well-being across subgroups, and multiple linear regression modeling to identify predictors of psychological well-being.

The study period is from September 2025 to December 2026. This research is investigator-initiated and self-funded. The results will provide an evidence-based foundation for designing tailored clinical and psychosocial interventions to improve mental health and quality of life in patients with type 2 diabetes.

Inclusion Criteria:

1. Adults aged 18 years or older with full legal capacity.
2. Clinically diagnosed with Type 2 Diabetes Mellitus and receiving ongoing outpatient care.
3. Able to read and understand Chinese questionnaires and complete self-administered forms.
4. Understand the study purpose and procedures and provide written informed consent.

Exclusion Criteria:

1. Presence of major psychiatric disorders (e.g., schizophrenia, bipolar disorder, major depressive disorder).
2. Moderate to severe cognitive impairment or dementia, as assessed by the clinical physician, making it impossible to complete the questionnaires.
3. Currently experiencing acute diabetic complications (e.g., diabetic ketoacidosis, hyperosmolar hyperglycemic state) or hospitalization.
4. Severe language or other communication barriers preventing expression of consent or understanding of study content.

Adult patients (aged 18 years and older) with a confirmed diagnosis of type 2 diabetes mellitus receiving ongoing outpatient care at the Metabolism Clinic of National Taiwan University Hospital. Approximately 350 participants will be recruited using convenience sampling during routine clinic visits. All participants must be able to read and understand Chinese questionnaires, complete self-administered forms, and provide written informed consent. The study does not include healthy volunteers or individuals without type 2 diabetes.

De-identified individual participant data that may be shared include questionnaire scores and coded demographic and clinical variables (e.g., age group, sex, diabetes duration, BMI category, HbA1c range, presence of complications). No directly identifiable information (such as names, ID numbers, or contact information) will be included. Data will be stored and shared only under institutional data-sharing agreements, following approval by the National Taiwan University Hospital Research Ethics Committee.

Beginning 12 months after publication of the main results; available for up to 5 years thereafter.

Qualified researchers may request access by submitting a written proposal and institutional data-sharing agreement to the Principal Investigator. Approval will be required from the National Taiwan University Hospital Research Ethics Committee prior to data release.