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Trial registered on ANZCTR


Registration number
ACTRN12622000069752
Ethics application status
Approved
Date submitted
1/12/2021
Date registered
20/01/2022
Date last updated
9/01/2023
Date data sharing statement initially provided
20/01/2022
Type of registration
Prospectively registered

Titles & IDs
Public title
Investigating the effect of a weight loss intervention on kidney disease progression: a randomised controlled feasibility study
Scientific title
A randomised controlled feasibility study exploring a low energy diet and weight management program in adults with obesity and kidney disease
Secondary ID [1] 305875 0
KHA2021HM
Universal Trial Number (UTN)
Trial acronym
SLOW CKD feasibility study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Kidney disease 324424 0
Obesity 324425 0
Condition category
Condition code
Diet and Nutrition 321920 321920 0 0
Obesity
Renal and Urogenital 321921 321921 0 0
Kidney disease

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
*Low energy diet stage 12 weeks

>>> Diet
Intervention group participants will follow a three-month low energy diet (LED) (~3400 to 3700 kJ, ~80g protein per day), using 3 to 4 commercial meal-replacements (Optifast, Nestle each product ~840 to 950 kJ) + 0-1 low energy food items + 2 cups of low carbohydrate vegetables every day + encouraged to consume x 1 tsp of oil and 2 litres of energy free beverages per day (preferably water). All meal replacements for the duration of the study will be provided to participants.

Low energy foods are defined as individually portioned snacks with an energy content of 800-1000kJ, such as 1 packet breakfast biscuits (Belvita, 50g), 1 breakfast bakes bar (uncle Toby's, 65g), 1 packet of nuts, or nuts and seeds (Luck,y 30g), 1 snack packet of cheese and crackers (5 cheese slices, 5 crackers, 50g), 1 small tin salt reduced baked beans (Heinz, 220g), 1 red kidney bean salad (Edgell, 200g), 1 tuna and crackers snack pack (Woolworths, 112g), 1 tuna & pasta/quinoa/beans (Woolworths, tuna & pasta marinara sauce 170g, tuna & pasta Sicilian style 170g, tuna & quinoa Asian style 185g, tuna & beans Mexican style 185g, 1 tuna ready to eat (Sirena, Sicilian style pasta with tuna 170g, Italian style salad with tuna 170g, kale & quinoa salad with tuna 170g), or 1 tuna meal (John West, tuna & beans, capsicum, sweet corn, red kidney beans & chilli 185g, tuna lunch kit thousand island dressing 108g, protein + iron tuna with roasted capsicum & three bean mix 170g, protein + magnesium tuna with brown rice, chargrilled corn, black beans, lime & chilli 170g)

The initial appointment (30 min) will include written and verbal information for the diet and for fluid intake and outline the group support program. Written information has been developed specifically for this study and includes written and pictorial information on the commercial meal-replacements and low energy foods.

To support participants in this stage, they will have fortnightly contact with a specialist kidney dietitian (minimum 5 years’ experience) in a structured education support group (6 x 45 minute sessions) using telehealth, and an optional virtual patient support group (using a group chat app) to share experiences and encouragement in this stage. THe maximum group size will be 8 participants. Structured education (a combination of teaching, practical activities and discussion in the group and self monitoring between sessions) will include awareness of hunger and satiety and eating habits, reasons for eating, and problem solving using a motivational interviewing approach. Additional telephone/text message/telehealth support will be available for participants as clinically appropriate during the low energy diet stage. Time spent in additional support will be based on clinical need as assessed by the research dietitian.

Participants in the intervention group will have a “kidney” blood test 2-4 weeks after commencing the low energy diet, to monitor serum electrolytes, creatinine (and estimated eGFR) and lipids. The results will be screened by the study site Dietitian or research nurse, and any results out of usual range for the participant highlighted, and all results sent to the nominated study nephrologist for review. The nephrologist will review, sign, and date the results and indicate ‘NCS’ if not clinically significant or ‘CS’ next to a particular result if deemed clinically significant. All clinically significant results will be sent to the participant’s usual kidney specialist for review and the intended action documented and communicated to the participant and participant’s General Practitioner (GP) by a member of the study team. The frequency of any ongoing monitoring of blood tests or symptoms will be determined by the usual kidney specialist and carried out by the study team.

>>>Physical activity
Participants' will be instructed to continue physical activity and exercise habits during this LED phase.

Adherence will be monitored using attendance checklists and meal replacement + snack diaries.

*Food reintroduction and lifestyle adaptation stage 12 weeks

>>>Eating and Physical Activity
Immediately following the LED stage, participants will initially attend fortnightly and then monthly 45 minute facilitated telehealth group sessions, for a further 3 months (a total of 4 sessions across 3 months, facilitated by an experienced kidney dietitian with > 5 years experience and an accredited Clinical Exercise Physiologist), to support the introduction of a physical activity program, develop healthy eating, self-efficacy, strategies to change habits, new normal routines for eating and physical activity and for peer support. The virtual patient support group will continue during this stage.

Food re-introduction will occur in a planned stepwise manner and pragmatically in line with participant readiness, with goal intakes increasing to 6000 kJ/day, through to standard energy requirements minus 2000 kJ/day, for ongoing weight loss, capped at 10 000 kJ/day. If weight regain of >2kg occurs, participants will be encouraged to use meal replacements for 1-2 meals per day for 1-2 weeks, and will receive additional support and review of barriers/eating/activity for weight loss maintenance.

Individualised, graded physical activity plans will be developed with the study Accredited Exercise Physiologist (minimum 2 years’ experience) - based on self-identified activity goals, and activity tracked and monitored virtually with a phone/tablet/computer app. The individual program is based on exercise recommendations and guidelines from the American College of Sports Medicine. The program will include a combination of upper and lower body movements (e.g. TheraBand chest press and row, bicep curl, sit to stand, hip bridge and leg curl exercises), cardiovascular exercise (e.g walking, jogging and cycling), and mobility exercises (e.g.stretching, wall angels, roll downs and knee rocks), with an overall aim to increase strength, maintain or improve muscle mass, and improve cardiovascular fitness. The intensity and volume of exercise is based on the participants medical history, disease state, goals and identified barriers, aiming to progressively increase to at least 150 minutes of physical activity per week.

The physical activity program is entered into the PhysiTrak software for participants to complete at home in their own time. Participants enter their exercise into Physitrak and this is monitored by the exercise experts in the study team on a weekly basis. In alignment with previous research the participants will be supported through fortnightly to monthly sessions using telehealth (4 x 45-minute sessions). Additional support by telephone, text message and telehealth is available to participants if requested, or if planned exercise is not recorded as completed.

All participants attend usual kidney clinic visits with treatment aiming for optimal blood pressure, lipid and glycaemic control with standard medical therapies treating to national guidelines. There will be no change to frequency of usual nephrologist care or general practitioner shared care monitoring. There will be no change to referral criteria for dietitian consultations.

A sub-sample of participants will be invited to complete semi-structures interviews to provide information about participant experience during the study. All participants will be offered the opportunity to participate until the required sample of 6-8 participants from the intervention group is reached.
Intervention code [1] 322273 0
Lifestyle
Intervention code [2] 322484 0
Treatment: Other
Comparator / control treatment
The control group will receive usual care. Participants will attend usual kidney clinic visits with treatment aiming for optimal blood pressure, lipid and glycaemic control with standard medical therapies treating to national guidelines. There will be no change to frequency of usual nephrologist care or general practitioner shared care monitoring. There will be no change to referral criteria for dietitian consultations. Recommendation for weight loss in usual care varies between clinicians; most guidelines recommend achieving a healthy weight. Referral to community healthy lifestyle programs may occur.

A sub-sample of participants will be invited to complete semi-structures interviews to provide information about participant experience during the study. All participants will be offered the opportunity to participate until the required sample of 6-8 participants from the usual care group is reached.
Control group
Active

Outcomes
Primary outcome [1] 329667 0
Feasibility success will be determined if the intervention is safe and if two or more feasibility criteria are met (composite outcome):
Feasibility criteria
1. Recruitment rate - at least 25% of all eligible patients who can be contacted are recruited
2. Retention rate - at least 75% of recruited intervention participants maintained at 6 months
3. Weight loss - at least 30% of participants are able to achieve at least 10 kg weight loss at 3 months

Definitions:
Recruitment rate
Recruitment rate will be measured as the number of patients recruited from the pool of eligible patients referred to the study and invited to participate within the recruitment period. Refusal will be recorded with descriptive demographic data such as age; aetiology of primary diagnosis; gender; location and reason for refusal, if willing to disclose. Recruitment rate will be determined by an audit of study enrolment logs.

Retention rate
Study retention will be calculated as the inverse of attrition (due to drop-out or safety concerns) at 12 and 26 weeks. Retention rate will be determined by an audit of study visit logs.

Weight loss
The number and percentage of consenting participants allocated to the intervention who achieve at least 10kg weight loss at 3 months. Weight loss will be determined as the difference between weight at baseline and 12 weeks.
Timepoint [1] 329667 0
26 weeks post-enrolment
Primary outcome [2] 329705 0
Safety
The proportion of study-related serious adverse events assessed by the data monitoring committee at monthly meetings. Serious adverse events are death, life-threatening adverse event, inpatient hospitalisation or prolongation of existing hospitalisation, persistent/significant incapacity/substantial disruption of the ability to conduct normal life functions. Serious adverse events will be assessed through participant reporting and clinician researcher examination of medical records.

Timepoint [2] 329705 0
26 weeks post-enrolment
Secondary outcome [1] 403694 0
Participant experience of randomisation and participation in the study, and in intervention group participants, adherence to a low energy diet and the benefits and difficulties of making significant lifestyle changes, via semi-structured telephone interviews (sub sample n=12 in total from both groups)
Timepoint [1] 403694 0
13 weeks post-enrolment
Secondary outcome [2] 403695 0
Quality of life will be measured using the EQ-5D-5L quality of life questionnaire
Timepoint [2] 403695 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [3] 403696 0
Fatigue will be measured using the FACIT fatigue scale version 4
Timepoint [3] 403696 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [4] 403697 0
Sleep quality will be measured using the Pittsburgh sleep quality index (PSQI)
Timepoint [4] 403697 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [5] 403698 0
Change in Body weight (kg) measured with digital scales
Timepoint [5] 403698 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [6] 403699 0
Seated resting blood pressure assessed using a sphygmomanometer
Timepoint [6] 403699 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [7] 403700 0
Albuminuria assessed by urinary albumin to creatinine ratio
Timepoint [7] 403700 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [8] 403701 0
Blood lipids (total cholesterol, high density lipoprotein [HDL] cholesterol, low density lipoprotein [LDL] cholesterol and triglycerides) assed by blood test
Timepoint [8] 403701 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [9] 403702 0
Changes in medication for CVD risk reduction (antihypertensives, statins, antihyperglycaemic agents) will be assessed by study specific medication questionnaire.
Timepoint [9] 403702 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [10] 403703 0
Serum creatinine assessed by blood test
Timepoint [10] 403703 0
Week 0 and week 26 post-enrolment
Secondary outcome [11] 403705 0
Aerobic exercise capacity assessed by six minute walk test
Timepoint [11] 403705 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [12] 403706 0
Dietary intake (composite outcome) (macronutrient intake and food groups) assessed by collation of responses to a semi quantitative food frequency questionnaire (EPIC FFQ) with recall of typical diet over the last 2 months.
Timepoint [12] 403706 0
Week 0 and week 26 post-enrolment
Secondary outcome [13] 403707 0
Episodes of adverse events - such as hyperkalaemia, dizziness, fainting, constipation, dehydration, acute kidney injury, postural hypotension, hypoglycaemia, unplanned hospital admission, falls, musculoskeletal injuries and other unexpected adverse events will be recorded and reported as episodes by intervention group
Timepoint [13] 403707 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [14] 404409 0
Serum cystatin-C assessed by blood test
Timepoint [14] 404409 0
Week 0 and week 26 post-enrolment
Secondary outcome [15] 404410 0
eGFR assessed by blood test adjusted and unadjusted for body surface area measured using the CKD-EPI equation
Timepoint [15] 404410 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [16] 404419 0
Percentage change in body weight calculated by:
Post intervention weight (measured by digital scales) - baseline body weight (measured by digital scales) / baseline body weight (measured by digital scales) x 100

Timepoint [16] 404419 0
Week 13 and week 26 post-enrolment
Secondary outcome [17] 404420 0
Proportion (count) of participants with weight loss of greater than or equal to 5kg, 5 to 10kg, 10 to 15kg and greater than or equal to 15kg calculated from Change in Body weight (kg) data measured with digital scales
Timepoint [17] 404420 0
Week 13 and week 26 post-enrolment
Secondary outcome [18] 404422 0
Leg strength and endurance assessed by the sit to stand test 30 second test
Timepoint [18] 404422 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [19] 404423 0
Hand grip strength assessed using a dynamometer
Timepoint [19] 404423 0
Week 0, week 13 and week 26 post-enrolment
Secondary outcome [20] 404424 0
Physical activity sessions completed tracked using PhysiTrack software (PhysiApp)
Timepoint [20] 404424 0
Week 13 and week 26 post-enrolment

Eligibility
Key inclusion criteria
Participants will be considered eligible when they meet the following inclusion criteria:
1. Adults aged 18 to 75 years, and able to consent in English, and
2. BMI greater than or equal to 30 kg/m2 and
3. eGFR greater than or equal to 30ml/min/1.73m2 (CKD-EPI eGFR) and
4. Persistent albuminuria with urinary albumin to creatinine ratio (uACR greater than or equal to 3 mg/mmol)
Minimum age
18 Years
Maximum age
75 Years
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
This study will exclude participants that do not satisfy the above inclusion criteria, or:
1. Previous or planned bariatric surgery within the next 12 months
2. Intentional weight loss > 5 % within the previous six months
3. Pregnancy or breastfeeding
4. Kidney transplant recipient
5. Unable to access smartphone, tablet or computer device
6. Significant psychiatric or psychological disorder including presence of an eating disorder or purging behaviour
7. Have an allergy or dietary intolerance, or condition whereby a formulated meal replacement or commercially prepared meal would be unsafe

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Random sampling numbers were drawn up by an independent statistician and uploaded into a central randomisation computer software system REDCaps.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Randomisation and stratification sequence generation will be performed by an independent statistician using randomisation software.
Randomisation will be implemented by the trial coordinator using the REDCap research management system which will implement the statisticians schedule. Randomisation will be stratified across presence or absence of diabetes. The investigator inform the consenting participant of their assigned intervention at their baseline appointment after their baseline assessments have been undertaken.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?


The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Parallel
Other design features
Phase
Not Applicable
Type of endpoint/s
Safety
Statistical methods / analysis
Proportions and percentages will be calculated for the feasibility outcomes. Measures of central tendency (means and variance) will be calculated for clinical and patient focused outcomes. Bland Altman plots with 95% limits of agreement for mean vs difference between GFR and eGFR will be constructed. Framework analyses will identify themes in the qualitative data.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
28/02/2022
Actual
8/03/2022
Date of last participant enrolment
Anticipated
1/03/2023
Actual
Date of last data collection
Anticipated
29/09/2023
Actual
Sample size
Target
50
Accrual to date
30
Final
Recruitment in Australia
Recruitment state(s)
QLD
Recruitment hospital [1] 21190 0
Princess Alexandra Hospital - Woolloongabba
Recruitment hospital [2] 21192 0
Royal Brisbane & Womens Hospital - Herston
Recruitment hospital [3] 21226 0
Redland Hospital - Cleveland
Recruitment postcode(s) [1] 36056 0
4102 - Woolloongabba
Recruitment postcode(s) [2] 36057 0
4163 - Cleveland
Recruitment postcode(s) [3] 36058 0
4029 - Herston

Funding & Sponsors
Funding source category [1] 310225 0
Charities/Societies/Foundations
Name [1] 310225 0
Kidney Health Australia
Country [1] 310225 0
Australia
Primary sponsor type
University
Name
Queensland University of Technology
Address
Victoria Park Road
Kelvin Grove Qld 4059
Country
Australia
Secondary sponsor category [1] 311322 0
None
Name [1] 311322 0
Address [1] 311322 0
Country [1] 311322 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 309909 0
Royal Brisbane & Women’s Hospital Human Research Ethics Committee
Ethics committee address [1] 309909 0
Level 2, Building 34
Royal Brisbane & Women’s Hospital Butterfield Street, Herston Qld 4029
Ethics committee country [1] 309909 0
Australia
Date submitted for ethics approval [1] 309909 0
23/07/2021
Approval date [1] 309909 0
02/09/2021
Ethics approval number [1] 309909 0
HREC/2021/QRBW/76570

Summary
Brief summary
Currently, there are no published trials examining the effect of non-surgical weight loss interventions on CKD progression in those with obesity and CKD. Clinical trials, utilising an effective non-surgical method of low energy meal replacements or prep-prepared meals plus specialised support over the longer term, are needed to determine whether weight loss can reduce cardiovascular risk factors, improve quality of life and delay progression of kidney disease. Before undertaking a definitive trial, the safety, feasibility and acceptability of low energy diets should be tested in patients with kidney disease. Our study has the potential to benefit patients if we can offer an acceptable and effective non-surgical weight loss intervention to potentially modify the course of CKD associated with obesity.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 115798 0
Dr Helen MacLaughlin
Address 115798 0
School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology - 149 Victoria Park Rd, Kelvin Grove QLD 4059

Department of Nutrition and Dietetics, Royal Brisbane and Women’s Hospital - Butterfield St, Herston QLD 4029
Country 115798 0
Australia
Phone 115798 0
+61 479137338
Fax 115798 0
Email 115798 0
[email protected]
Contact person for public queries
Name 115799 0
Helen MacLaughlin
Address 115799 0
School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology - 149 Victoria Park Rd, Kelvin Grove QLD 4059

Department of Nutrition and Dietetics, Royal Brisbane and Women’s Hospital - Butterfield St, Herston QLD 4029
Country 115799 0
Australia
Phone 115799 0
+61 479137338
Fax 115799 0
Email 115799 0
[email protected]
Contact person for scientific queries
Name 115800 0
Helen MacLaughlin
Address 115800 0
School of Exercise and Nutrition Sciences, Faculty of Health, Queensland University of Technology - 149 Victoria Park Rd, Kelvin Grove QLD 4059

Department of Nutrition and Dietetics, Royal Brisbane and Women’s Hospital - Butterfield St, Herston QLD 4029
Country 115800 0
Australia
Phone 115800 0
+61 479137338
Fax 115800 0
Email 115800 0
[email protected]

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.