Effect of a Plant-Focused Diet on Nutritional Status in Malnourished Peritoneal Dialysis Patients

Dietary intake collected from analysis of 3-day dietary recalls (2 weekdays, 1 weekend), using Nutritionist Pro software.

Dietary adequacy is assessed based on the comparison of each participant's macro- and micro-nutrient intakes against their estimated nutrient requirements. A deviation of more than 20% from the requirement will be classified as dietary inadequacy. Data will be summarised as percentage of participants meeting vs. not meeting adequacy.

Dialysis adequacy will be assessed using weekly Kt/V (urea), obtained from patients' medical records. A total Kt/V < 1.7 will be considered indicative of inadequate dialysis.

A renal function parameter, measured in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in µmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in g/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

A renal function parameter, measured in g/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

Post-dialysis weight will be measured in kilograms (kg), using a digital scale, with patients wearing light clothing and no heavy objects.

Height will be measured in centimeters (cm), with patients standing straight on the stadiometer, following the Frankfurt horizontal plane.

Body mass index will be calculated by dividing weight (kg) by the square of height (m²), recorded as kg/m².

Triceps skinfold will be assessed using skinfold callipers, recorded in centimetres (cm).

Patients will be required to complete a 3-day food diary (2 weekdays and 1 weekend). Food diaries will be reviewed monthly, either in person at clinic visits or remotely via phone or messaging, and will be scored using the binary dietary compliance scoring system developed specifically for this study. Using the scoring system (maximum score = 21), a total score of <10.5 out of 21 (<50%) will be classified as poor compliance, while a score of ≥10.5 out of 21 (≥50%) will be considered adequate. Scores range from 0 - 21, with higher scores indicating better compliance.

The scoring system will be pilot tested with patients during the first 2 weeks of the study period.

Each component (medical history, physical examination, BMI, and laboratory markers) is scored from 0 (normal nutrition status) to 3 (severe nutritional deficit). Total scores range from 0 to 30, with higher scores indicating higher degrees of malnutrition. A score of <5 indicates normal nutritional status, while ≥5 signifies malnutrition.

Evaluated using the Appetite and Food Satisfaction Questionnaire (AFSQ). Consists a facial hedonic scale to assess appetite levels and five additional questions. Each question is scored from 0 to 3, with a total score ranging from 0 to 18 and lower scores indicate better appetite and food satisfaction.

Evaluated using the World Health Organization Quality of Life-BREF (WHOQOL-BREF). It consists of 26 items categorized into four domains: physical health, psychological well-being, social relationships, and environment. Each item is rated on a 5-point Likert scale, and domain scores are calculated as the mean of their respective items. Raw domain scores are transformed to a 4-20 scale and further converted to a 0-100 scale to facilitate interpretation, with higher scores indicating better QOL

Assessed using the Short Physical Performance Battery (SPPB), with scores calculated and higher total scores indicating better physical function. Muscular strength will be measured using the Jamar handgrip dynamometer.

Evaluated using the International Physical Activity Short Form questionnaire. Total scores are calculated by summing the duration and frequency of all activities, while domain-specific and activity-specific sub scores are also determined. The collected data will be reported as either a continuous measure or in metabolic equivalents (METs) per minute.

The retention rate will be calculated as the percentage of participants who complete the 6-month study period. The number of participants completing the study will be divided by the total number enrolled and multiplied by 100.

Mid-upper arm circumference will be measured using a measuring tape, recorded in centimetres (cm).

Mid-arm muscle circumference (MAMC) will be calculated using the formula: MAMC = MUAC - (π × TSF). Measurements will be recorded in centimetres (cm). It serves as an anthropometric indicator of muscle mass and is used as a proxy for lean body mass when bioelectrical impedance analysis (BIA) is unavailable. A lower MAMC reflects reduced muscle reserves and potential malnutrition.

Serum total cholesterol, a parameter of the lipid profile, will be recorded in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges

Serum tryglycerides, a parameter of the lipid profile, will be recorded in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges

Serum High-density lipoprotein cholesterol (HDL-C), a parameter of the lipid profile, will be recorded in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges

Serum Low-density lipoprotein cholesterol (LDL-C), a parameter of the lipid profile, will be recorded in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges

Glycated haemoglobin (HbA1c), a parameter of the blood glucose profile, will be recorded in %, obtained from medical records. Results will be compared against standard laboratory reference ranges.

Fasting Blood Glucose (FBG), a parameter of the blood glucose profile, will be recorded in mmol/L, obtained from medical records. Results will be compared against standard laboratory reference ranges.

Serum Total Iron Binding Capacity (TIBC), an inflammatory marker, will be obtained from medical records and recorded in µmol/L. Results will be compared against standard laboratory reference ranges.

Serum hsCRP, an inflammatory marker, will be measured in mg/L. A 10 mL fasting blood sample (following a 12-hour overnight fast) will be collected by trained hospital staff using automated procedures. Samples will be analysed at an external accredited laboratory (Innoquest). Results will be compared against standard laboratory reference ranges.

Normalised protein catabolic rate (nPCR), a protein intake indicator, will be obtained from medical records and recorded in g/kg/day. Results will be compared against standard laboratory reference ranges.

Participants will complete a 34-item questionnaire adapted from a validated tool used in haemodialysis patients. It includes three subscales: knowledge (12 items), attitude (7 items), and practice (15 items). Knowledge items are scored 0-1 (correct/incorrect), while attitude and practice items are rated on a 0-4 Likert scale. Total scores range from 0 to 100, with higher total scores indicating better dietary KAP.

Body fat percentage will be measured in percentage (%) using a bioelectrical impedance analysis (BIA) device.

Fat-free mass will be assessed using a bioelectrical impedance analysis (BIA) device, recorded in kilograms (kg).

Skeletal muscle mass will be measured using a bioelectrical impedance analysis (BIA) device, recorded in kilograms (kg).

Fat mass will be measured using a bioelectrical impedance analysis (BIA) device, recorded in kilograms (kg).