Evaluation of a Novel Integrated Cross-border Clinical Healthcare Service Model to Increase Access to Care for People Living With Obesity (PEACETIME)

Quality of life will be assessed using the EQ-5D-5L, a validated patient-reported measure of health-related quality of life. The questionnaire assesses five dimensions: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression. Each dimension has five response levels ranging from no problems to extreme problems. Responses are combined to generate a health state profile and converted to a utility index score using the appropriate country-specific value set. Utility scores typically range from values below 0 (health states considered worse than death) to 1.0 (full health), with higher scores indicating better health-related quality of life. Participants will also complete the EQ Visual Analogue Scale (EQ-VAS), rating their overall health from 0 (worst imaginable health) to 100 (best imaginable health).

Body weight will be measured in kilograms (kg) using calibrated scales. Percentage total body weight loss (%TBWL) will be calculated as [((baseline weight - follow-up weight) ÷ baseline weight) × 100]. Higher %TBWL values indicate greater weight loss. The number and percentage of participants achieving clinically significant weight loss will be reported using thresholds of ≥5%, ≥10%, and ≥15% total body weight loss from baseline.

Glycated haemoglobin (HbA1c) will be measured from venous blood samples analysed by standard clinical chemistry methods. HbA1c reflects average blood glucose levels over the previous 2-3 months and will be reported in mmol/mol. Lower HbA1c values indicate better glycaemic control. Change in HbA1c from baseline to follow-up will be assessed.

Type 2 diabetes remission will be assessed using HbA1c measurements from venous blood samples analysed by standard clinical chemistry methods, together with review of diabetes diagnosis and medication use. Remission will be defined according to UK and international consensus criteria as HbA1c <48 mmol/mol (6.5%) maintained for at least 3 months in the absence of glucose-lowering medication. The number and percentage of participants meeting remission criteria at follow-up will be reported.

Physical activity will be assessed using the International Physical Activity Questionnaire (IPAQ) in Northern Ireland and by accelerometry in the Republic of Ireland. IPAQ measures walking, moderate-intensity activity, vigorous-intensity activity, and sitting time over the previous 7 days. Outcomes will include total moderate-to-vigorous physical activity (MVPA; minutes/week), total physical activity (MET-minutes/week), sitting time, and physical activity category (low, moderate, or high) according to the IPAQ scoring protocol. Accelerometer-derived outcomes will include objectively measured physical activity and sedentary behaviour. For participants who connect a compatible smartwatch to the digital health platform, daily step count data will also be collected and reported as average steps per day, with higher values indicating greater physical activity.

Depression symptoms will be assessed using the Patient Health Questionnaire-9 (PHQ-9). The PHQ-9 consists of 9 items assessing depressive symptoms experienced over the previous 2 weeks. Each item is scored from 0 ("Not at all") to 3 ("Nearly every day"), producing a total score ranging from 0 to 27. Higher scores indicate greater depression severity. Scores are categorised as minimal (0-4), mild (5-9), moderate (10-14), moderately severe (15-19), and severe (20-27).

Anxiety symptoms will be assessed using the Generalised Anxiety Disorder-7 (GAD-7) questionnaire. The GAD-7 consists of 7 items assessing anxiety symptoms experienced over the previous 2 weeks. Each item is scored from 0 ("Not at all") to 3 ("Nearly every day"), producing a total score ranging from 0 to 21. Higher scores indicate greater anxiety severity. Scores are categorised as minimal (0-4), mild (5-9), moderate (10-14), and severe (15-21).

Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI), a validated self-report questionnaire that measures sleep quality and disturbances over the previous month. The PSQI generates a global score ranging from 0 to 21, with higher scores indicating poorer sleep quality. A global score greater than 5 is commonly used to identify poor sleep quality. For participants who connect a compatible smartwatch to the digital health platform, objective sleep metrics, including sleep duration and sleep patterns, may also be collected. Higher sleep duration and improved sleep metrics indicate better sleep outcomes.

Adverse events will be recorded throughout the study and classified according to number, severity, relatedness to the intervention, and outcome. Severity will be categorised as mild, moderate, or severe. Information on actions taken, follow-up required, and resolution status will also be collected. The number and proportion of participants experiencing one or more adverse events, serious adverse events, and intervention-related adverse events will be reported. Higher numbers indicate a greater frequency of adverse events.

Brachial blood pressure will be measured in millimetres of mercury (mmHg) using a validated blood pressure monitor according to standard clinical procedures. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) will be recorded. Blood pressure is reported in mmHg, with lower values generally indicating better blood pressure control.

Lipid profile will be assessed from venous blood samples analysed using standard clinical chemistry methods. Measurements will include total cholesterol, low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and triglycerides, reported in mmol/L. Lower levels of total cholesterol, LDL-C, and triglycerides, and higher levels of HDL-C, are generally indicative of improved cardiovascular risk.

Liver function will be assessed from venous blood samples analysed using standard clinical chemistry methods. Measurements will include liver function markers such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transferase (GGT), alkaline phosphatase (ALP), and bilirubin, reported according to local laboratory standards. Lower liver enzyme levels within the normal reference range are generally indicative of improved liver health.

Urine albumin-creatinine ratio (ACR) will be measured from a spot urine sample analysed using standard clinical chemistry methods (Northern Ireland participants only). ACR is reported in mg/mmol and is used to assess kidney damage and monitor kidney health. Lower ACR values indicate lower levels of urinary albumin excretion and better kidney function. Changes in ACR from baseline to follow-up will be assessed, and the proportion of participants with elevated ACR values may also be reported.

Estimated glomerular filtration rate (eGFR) will be calculated from venous blood samples analysed using standard clinical chemistry methods. eGFR is reported in mL/min/1.73 m² and is used as a measure of kidney function. Higher eGFR values indicate better kidney function, while lower values indicate impaired kidney function.

Obesity- and disease-related complications will be identified from participants' medical records and clinical documentation. Complications may include, but are not limited to, type 2 diabetes, hypertension, dyslipidaemia, cardiovascular disease, obstructive sleep apnoea, chronic kidney disease, metabolic dysfunction-associated steatotic liver disease (MASLD), osteoarthritis, and other obesity-related comorbidities. The number and proportion of participants with one or more disease-related complications, as well as changes in complication status during follow-up, will be reported.

Quality of life will be assessed using the RAND 36-Item Short Form Health Survey (RAND-36), a validated self-reported measure of health-related quality of life. The questionnaire assesses eight domains: physical functioning, role limitations due to physical health, role limitations due to emotional problems, energy/fatigue, emotional well-being, social functioning, pain, and general health. Scores for each domain are transformed to a scale from 0 to 100, where higher scores indicate better health status and quality of life. Changes in domain scores from baseline to follow-up will be assessed.

Health empowerment will be assessed using the McGill Empowerment Assessment-Diabetes (MEA-D) (Northern Ireland participants only). The MEA-D is a validated 28-item self-report questionnaire that assesses empowerment across four domains: attitude, knowledge, behaviour, and relatedness. Items are rated on a 5-point Likert scale ranging from 1 (strongly disagree) to 5 (strongly agree). Domain scores are calculated as the mean of the items within each domain, with higher scores indicating greater health empowerment and engagement in diabetes self-management. Changes in domain scores and overall empowerment from baseline to follow-up will be assessed.

Self-efficacy will be assessed using the General Self-Efficacy Scale (GSE), a validated 10-item self-report questionnaire that measures an individual's confidence in their ability to cope with challenges and achieve goals. Each item is scored on a 4-point scale ranging from 1 ("Not at all true") to 4 ("Exactly true"). Item scores are summed to produce a total score ranging from 10 to 40, with higher scores indicating greater self-efficacy and confidence in managing health-related behaviours. Changes in total GSE score from baseline to follow-up will be assessed.

Medication use will be assessed from participant self-report and/or medical records. Information collected will include the number of prescribed medications, medication class, and daily dose. Changes in medication use from baseline to follow-up will be evaluated, including initiation, discontinuation, dose reduction, or dose escalation. Where applicable, changes in the use of medications for obesity-related conditions such as type 2 diabetes, hypertension, dyslipidaemia, and cardiovascular disease will be reported. Lower medication burden and/or reductions in medication dose may indicate improvement in disease management.

Healthcare utilisation will be assessed through participant self-report and/or routine healthcare records. Measures will include the number and duration of hospital admissions, emergency department attendances, outpatient appointments, primary care consultations, and other health and social care resource use. Outcomes will be included in the health economics assessment of the programme. Lower healthcare utilisation may indicate improved health status and reduced service demand.

Out-of-pocket expenditure and productivity losses will be assessed using a participant-completed resource-use log. Data collected will include personal expenses related to healthcare, weight management, travel, and other relevant costs, as well as time missed from usual activities, including paid employment, education, caregiving, and homemaking responsibilities. Outcomes will be included in the health economics assessment of the programme. Higher values indicate greater economic burden and productivity loss.

Body composition will be assessed using bioelectrical impedance analysis (BIA) and waist:hip ratios. Measurements will include body fat percentage, fat mass, and lean mass, reported in standard units (kg or %). Waist-to-hip ratio will be calculated by dividing waist circumference by hip circumference, measured according to standard clinical procedures. Higher body fat measures and waist-to-hip ratios indicate greater adiposity and cardiometabolic risk, while higher lean mass and lower waist-to-hip ratios indicate a more favourable body composition.

Obesity stigma will be assessed among healthcare professionals using the Fat Phobia Scale (FPS) and among participants using the Modified Weight Bias Internalization Scale (WBIS-M). The FPS measures explicit weight-related attitudes and stereotypes towards people living with obesity, with higher scores indicating greater obesity-related stigma. The WBIS-M is a self-report measure of internalised weight stigma, assessing the extent to which individuals apply negative weight-related stereotypes to themselves. WBIS-M items are rated on a 7-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree), with item scores averaged to produce an overall score ranging from 1 to 7. Higher WBIS-M scores indicate greater internalised weight stigma.

Digital literacy will be assessed at baseline through participant self-report of access to and experience with smartphones, tablets, internet connectivity, and activity trackers. Usability of the digital health platform will be assessed using the mHealth App Usability Questionnaire (MAUQ) for both participants and healthcare professionals. The MAUQ is a validated questionnaire assessing ease of use, interface and satisfaction, and usefulness of mHealth applications. Items are rated on a 7-point Likert scale ranging from 1 (strongly disagree) to 7 (strongly agree). Item scores are averaged to produce an overall usability score ranging from 1 to 7, with higher scores indicating greater usability and satisfaction with the digital health platform.

Nutritional status will be assessed using venous blood samples analysed by standard clinical chemistry methods. Measurements will focus on key micronutrients of concern and will be reported according to standard laboratory units and reference ranges. Higher values within the normal reference range indicate improved nutritional status.

Patient satisfaction with the PEACETIME programme will be assessed using a survey incorporating relevant validated Patient-Reported Experience Measures (PREMs) and qualitative interviews. Quantitative survey responses will be reported using the scoring system of the selected PREM(s), with higher scores indicating greater satisfaction and a more positive participant experience where applicable. Qualitative interviews will explore participants' experiences, perceived benefits, barriers to engagement, and suggestions for programme improvement.

Patient retention and engagement will be assessed throughout the programme. Retention will be measured as the number and percentage of participants who remain enrolled and complete follow-up assessments. Engagement with the digital health platform will be assessed using platform analytics, including frequency of logins, time spent using the platform, completion of programme activities, and interaction with digital resources and coaching support. Higher retention rates, greater engagement frequency, and increased time spent using the platform indicate greater programme participation and engagement. Changes in engagement over the course of the programme will also be evaluated.