Fostering Self-Empowerment in CKD Patients Through Food Choice Mapping

Physical Health-Related Quality of Life At baseline and Week 12-16, physical health-related quality of life will be assessed using the 12-Item Short Form Health Survey (SF-12). The Physical Component Summary (PCS) score ranges from 5 to 20, with lower scores indicating better health-related quality of life and higher scores indicating poorer health-related quality of life.

At baseline and Week 12-16, mental health-related quality of life will be assessed using the 12-Item Short Form Health Survey (SF-12). The Mental Component Summary (MCS) score ranges from 12 to 45, with lower scores indicating better health-related quality of life and higher scores indicating poorer health-related quality of life.

At baseline and Week 12-16, nutrition-related empowerment will be assessed using a modified version of the Korean Health Empowerment Scale (K-HES). The scale consists of 8 items scored from 1 (Strongly Disagree) to 5 (Strongly Agree). Item scores are summed to generate a total score ranging from 8 to 40, with higher scores indicating greater nutrition-related empowerment and self-management capacity.

Participants will rate the ease of adhering to their prescribed diet plan when eating out using a 5-point scale ranging from 1 (very difficult) to 5 (very easy). Higher scores indicate greater ease of dietary adherence.

Participant engagement with the nEAT mobile application will be assessed by the proportion of scheduled food diary entries completed during the intervention period. Food diary completion rate (%) = (Number of completed food diary entries ÷ Total number of scheduled food diary entries) × 100. A food diary entry is considered completed when the participant records the required dietary information for the scheduled eating occasion within the nEAT mobile application

Body weight will be measured at baseline and Week 12-16 using a calibrated weighing scale. Weight will be reported in kilograms (kg). Body weight change (kg) = Body weight at Week 12-16 - Body weight at baseline. Negative values indicate a reduction in body weight (weight loss), positive values indicate an increase in body weight (weight gain), and a value of 0 indicates no change in body weight.

Percentage weight change over the preceding 6 months will be calculated from self-reported and/or documented body weight records. Weight change will be reported as a percentage (%).

Body mass index (BMI) will be calculated as weight (kg) divided by height squared (m²), expressed as kg/m². BMI Asian categories are

Underweight: Less than 18.5 kg/m² Normal range: 18.5 to 22.9 kg/m² Overweight (At risk): 23.0 to 24.9 kg/m² Obese (Class I): 25.0 to 29.9 kg/m² Obese (Class II): ≥ 30.0 kg/m²

Nutritional status will be assessed using the Subjective Global Assessment (SGA), incorporating recent weight loss, dietary intake, gastrointestinal symptoms, functional status, muscle wasting, fat wasting, oedema, and overall nutritional status. Overall subjective scores range from 1 to 7, where 1-2 indicates severely malnourished, 3-5 moderately malnourished and 6-7 indicates being well nourished.

Participants will rate the ease of adhering to their prescribed diet plan when eating at home before and after using nEAT mobile application using a 5-point scale ranging from 1 (very difficult) to 5 (very easy). Higher scores indicate greater ease of dietary adherence.

Energy intake will be assessed using 24-hour dietary recalls completed at baseline and end of study at 12-16 weeks. Individual energy requirements will be estimated using the Harris-Benedict equation based on age (years), weight (kg), and height (cm), and used to establish personalized energy targets. Energy intake will be expressed as a percentage of the estimated energy requirement (%), calculated as actual energy intake divided by estimated energy requirement × 100. Values closer to 100% indicate greater adherence to prescribed energy targets.

Protein intake will be assessed using 24-hour dietary recalls completed at baseline and end of study at 12-16 weeks. Individual actual protein requirements will be estimated using the factor 0.8g/kg x weight (kg), and used to establish personalized energy targets. Protein intake will be expressed as a percentage of the estimated protein requirement (%), calculated as actual protein intake divided by estimated protein requirement × 100. Values closer to 100% indicate greater adherence to prescribed energy targets.

Sodium intake will be assessed using 24-hour dietary recalls completed at baseline and end of study at 12-16 weeks. Individual sodium allowance will limited to 2000mg per person . Energy intake will be expressed as a percentage of the sodium allowance (%), calculated as actual sodium intake divided by estimated sodium allowance × 100. Values closer to 100% indicate greater adherence to prescribed sodium targets.

Phosphorus intake will be assessed using 24-hour dietary recalls completed at baseline and end of study at 12-16 weeks. Individual phosphorus allowances will be personalised and estimated proportionally to protein intake. Phosphorus intake will be expressed as a percentage of the estimated phosphorus allowance (%), calculated as actual phosphorus intake divided by estimated phosphorus allowance × 100. Values closer to 100% indicate greater adherence to prescribed phosphorus targets.

Potassium intake will be assessed using 24-hour dietary recalls completed at baseline and end of study at 12-16 weeks. Individual potassium allowance will calculated at 39mg/kg per person, however, will be personalised based on the chronic kidney stage and serum biochemistry potassium. Potassium intake will be expressed as a percentage of the individualised potassium allowance (%), calculated as actual sodium intake divided by estimated potassium allowance × 100. Values closer to 100% indicate greater adherence to prescribed potassium targets.

Estimated glomerular filtration rate (eGFR), a laboratory-based measure of kidney function, will be assessed at baseline and at the end of the study (12-16 weeks). eGFR will be reported in millilitres per minute per 1.73 m² (mL/min/1.73 m²). The outcome measure will be the change in eGFR from baseline to study completion. Lower eGFR values compared to baseline indicate poorer kidney function.

Renal function will be assessed by measuring serum creatinine concentration and reported in micromoles per litre (µmol/L) at baseline and end of study at 12-16 weeks. Higher values from baseline indicate poorer or declining kidney function. Reference value, male: 54 - 101; female: 37 - 75 µmol/L

Serum potassium concentration will be measured and reported in millimoles per litre (mmol/L). Reference value: 3.6 - 5.0 mmol/L. Higher value from baseline signifies worsening of hyperkalemia

Nutritional status will be assessed using serum albumin concentration and reported in grams per litre (g/L) at baseline and end of study at 12-16 weeks. Higher values indicate better nutritional status compared to baseline. Reference value: 40 - 51 g/L

Hospital admissions related to chronic kidney disease or its complications occurring during the study period will be recorded and reported as the total number of admissions in comparison to the stratification of24-hour Diet Recall.