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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Date data sharing statement initially provided
Date results information initially provided
Type of registration
Prospectively registered

Titles & IDs
Public title
Optimising patient weight management prior to joint replacement to improve outcomes: a feasibility study with embedded qualitative component
Scientific title
An innovative low-inflammatory weight loss dietary program delivered pre-operatively targeting efficacy and safety, and costs of knee and hip arthroplasties in obese patients: a feasibility study with embedded qualitative component
Secondary ID [1] 297765 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obesity 312101 0
knee osteoarthritis 312102 0
hip osteoarthritis 312697 0
Condition category
Condition code
Diet and Nutrition 310763 310763 0 0
Musculoskeletal 310764 310764 0 0

Study type
Description of intervention(s) / exposure
Dietitian-led program (intervention group):
Participants will be assessed by the physiotherapist (PT) and the clinical nurse consultant (CNC) and managed according to the same principles as the usual care (comparator) group including consultation with the patient’s GP as required. Thus, the intervention - commencing at the point of entry to the waitlist program - will include advice regarding physical activity (to maintain muscle), pain management and chronic disease management, but will provide the anti-inflammatory weight loss diet in place of the usual diet information. The diet will be administered by an onsite dietitian (in the hospital clinic) who will use both 1-to-1 (in person and via telephone as required, delivered initially weekly (weeks 1 and 2) then fortnightly (weeks 4 and 6), followed by 4-weekly contact for the remainder of the program (nine months after recruitment) and group consultations to deliver the program (4 x group sessions with a focus on key elements of the LIFT-diet: extra virgin olive oil, foods high in lutein, anthocyanins, and anti-oxidants (including vitamin C rich foods), fish and legumes). The program will be personalised in order to accommodate cultural and special dietary requirements. The program will recommend energy intake be reduced by up to 500 calories/day and will follow the principals of a low-inflammatory diet such as those recommended by the Harvard Medical School The diet material will build on material developed by CI Flood for a concurrent study (among people with non-alcoholic fatty liver disease). The LIFT-diet, will emphasise foods rich in antioxidants, polyphenols (including anthocyanins, flavanols), carotenoids (particularly lutein and lycopene), long-chain omega-3 fatty acids, low-glycemic index foods and will provide advice to reduce pro-inflammatory foods, such as refined carbohydrate foods, highly processed take-away food items, sugary drinks, processed meat, alcoholic beverages and saturated and trans fat food sources. The LIFT-diet will include advice to consume tomatoes (good source of lycopene, oxylipin and coumarin), dark green leafy vegetables (good lutein source), fruit (e.g. strawberries, blueberries, oranges and cherries) (good anthocyanin source), legumes, spices and herbs (daily), and nuts (e.g. walnuts, almonds and pistachio) (4-5x/week), and fatty fish (2x/week), and extra virgin olive oil (main fat source, used daily; good source of polyphenolic compounds). This diet is not only anti-inflammatory but lower in energy intake, with the emphasis on reducing highly processed food items. Due to the vast ethnocultural diversity of South-West Sydney, we will work with consumer partners to aid the applicability of the education material to such populations, incorporating material suitable for traditional diets including information about food preparation and recipes. ‘Consumer partners’ will comprise members of the SPHERE MSK CCC and people the latter invite to contribute from their respective community connections.
As for the usual care group, the participant will be referred back to their GP if a change in their health or weight necessitates a review.
Adherence to the diet will be assessed using dietary surveys. Participants will be encourage to adhere at each visit with the dietitian.

For the qualitative component, a purposive sample of people (based on their level of weight loss - change within 5% of baseline weight; loss 5% or more of baseline; gain 5% or more of baseline) from this group will be interviewed about the barriers and enablers to weight loss.

Intervention code [1] 314083 0
Intervention code [2] 314084 0
Treatment: Other
Comparator / control treatment
Usual care (comparison group): Usual care will comprise assessment by a physiotherapist (PT) and nurse (CNC) at Baseline and the PT again at 3-months following their baseline assessment. Participants will have a final review by either the CNC or PT just prior to surgery (~ 9-12 months). During these assessments, the CNC will assess their medical comorbidities in the context of fitness for surgery and their ongoing management of these comorbidities in consultation with their General Practitioner. This includes but is not limited to cardiovascular, endocrine, respiratory, renal, urological and vascular conditions. Some routine blood tests are taken to assess the presence and extent of comorbid conditions commonly associated with obesity. The PT will provide advice addressing weight management, physical activity (to maintain muscle and assist with aerobic capacity including education around the National Physical Activity Guidelines, pain management, and chronic disease management as applicable, based on the model of care stipulated by the osteoarthritis chronic care program (OACCP). For the participating hospitals, that typically means patients are referred to relevant health professionals through their General Practitioner or existing community and hospital programs. Examples may include but are not limited to allied health practitioners through the chronic disease management items, medical specialists such as cardiologists and endocrinologists, hospital- and community-based falls prevention programs such as “Stepping On”, the NSW Health ‘Get Healthy’ service [], local leisure centres/pools or hospital diabetes clinics as examples. In between the face-to-face reviews that occur with the patients, the PT will have phone contact with the patient according to clinical need guided by OACCP model of care and using behaviour change and health coaching principles.
Using the routine blood tests and/or other information provided by the patient, participants are referred to their GP if their health or their weight changes, so that medication doses and other markers of health can be reviewed. Changes that may necessitate a review include if the participant reports new signs and symptoms, blood test results are abnormal, or body weight has changed significantly (= 5% change from initial).

For the qualitative component, a purposive sample of people (based on their level of weight loss - change within 5% of baseline weight; loss 5% or more of baseline; gain 5% or more of baseline) from this group will be interviewed about the barriers and enablers to weight loss.
Control group

Primary outcome [1] 319614 0
Feasibility and treatment fidelity outcome: Adherence to the dietary program - people in the intervention group demonstrate a higher score (out of 100) measured using the Medicul Food Frequency Questionnaire (FFQ)
Timepoint [1] 319614 0
At the time of surgery (approximately 10-12 months after study commencement)
Primary outcome [2] 319617 0
Feasibility outcome: estimated sample size to detect a relevant difference in 90-day complication rate between two groups. A sample of < 1200 will be considered feasible for 2 sites
Timepoint [2] 319617 0
90-days post-surgery
Primary outcome [3] 319618 0
Feasibility outcome: rate of recruitment. Expect a minimum enrolment of 60% of those eligible.
Timepoint [3] 319618 0
End of recruitment (about 3-4 months post study commencement)
Secondary outcome [1] 368861 0
Post-surgical complication (includes wound-related, revision surgery, cardiovascular events, bleeding, venous thromboembolism, death, cerebrovascular events, infection (any site), urinary retention, any operation within 30 days post-surgery, any organ failure, electrolyte disturbances requiring management, escalated management of diabetes or hypertension following surgery (eg manifestation of poor control that persisted beyond day 3 and required an escalation of management)), and adverse events acutely (falls, allergic reactions, pressure sores). These will be assessed via medical record review.
Timepoint [1] 368861 0
acute period to 90 days post-surgery
Secondary outcome [2] 368872 0
Feasibility outcome: Compliance with undertaking blood tests. Expect at least 75% to undertake the test at baseline and just prior to surgery.
Timepoint [2] 368872 0
Baseline, and just prior to surgery
Secondary outcome [3] 368873 0
Efficacy and treatment fidelity outcome: Weight loss (kg) (baseline minus weight at measured time point). Weight will be objectively measured at each time point via digital scale.
Timepoint [3] 368873 0
at 6 months and just prior to surgery (~10 months post study commencement); 90-days post-surgery
Secondary outcome [4] 368874 0
Feasibility and treatment fidelity outcome: Attendance at consultations with a dietitian (count) over the time period waitlisted for surgery
Timepoint [4] 368874 0
Measured over time period waitlisted for surgery
Secondary outcome [5] 368876 0
Monitored variable - Physical activity - average step count per day, using ActivPal device.
Timepoint [5] 368876 0
Baseline, 6 months and just prior to surgery (~10 months)
Secondary outcome [6] 368877 0
Waist circumference (cm) measured using a flexible tape measure
Timepoint [6] 368877 0
Baseline, 6 months, just prior to surgery, 90-days post surgery
Secondary outcome [7] 368878 0
Efficacy outcome: Index joint pain (numerical rating scale (11-point scale)
Timepoint [7] 368878 0
Baseline, 6 months, just prior to surgery, 90-days post-surgery
Secondary outcome [8] 368879 0
Safety and efficacy variable: 30-second sit to stand test.
Timepoint [8] 368879 0
Baseline, 6 months, just prior to surgery, and 90-days post-surgery
Secondary outcome [9] 368880 0
Efficacy and treatment fidelity variable: Blood biomarker - Interleukin 6
Timepoint [9] 368880 0
Baseline, 6 months, just prior to surgery
Secondary outcome [10] 368881 0
Monitored variable/potential effect modifier): Fibromyalgia score using a fibromyalgia survey (Fibromyalgia criteria and severity scale)
Timepoint [10] 368881 0
Baseline, 6 months, just prior to surgery, 90-days post surgery
Secondary outcome [11] 368883 0
Compliance outcome: Medas FFQ score
Timepoint [11] 368883 0
baseline, 6 months, just prior to surgery, 90-days post surgery.
Secondary outcome [12] 368884 0
Complaince outcome: Medicul FFQ score
Timepoint [12] 368884 0
just prior to surgery and 90-days post-surgery
Secondary outcome [13] 368887 0
Cost outcome: Staff cost of either program (hospital-based staff) and health resource use post-surgery (count of visits to health professionals). NSW Health salaries and FTE will be used for staff costs. Standard consultation rates for visits to health professionals will be used (through review of the MBS or NSW Allied Health Practitioner rates). This analysis will only be done if sufficient resources to do so.
Timepoint [13] 368887 0
up to 90-days post-surgery
Secondary outcome [14] 368889 0
Effectiveness outcome: Oxford knee or hip score (0-48) using the OKS or OHS
Timepoint [14] 368889 0
Baseline, 6-months, just prior to surgery and 90-days post-surgery
Secondary outcome [15] 368891 0
Effectiveness outcome: Euroqol 5D_5L today health score (0-100, visual analogue scale)
Timepoint [15] 368891 0
Baseline, 6-months, just prior to surgery, and 90-days post-surgery
Secondary outcome [16] 369988 0
Average time spent active using the ActivPal
Timepoint [16] 369988 0
Baseline, 6 months and just prior to surgery
Secondary outcome [17] 369989 0
Measure of inflammation (efficacy marker)- high sensitive CRP using a blood test
Timepoint [17] 369989 0
Baseline, 6 months and just prior to surgery
Secondary outcome [18] 369990 0
Measure of compliance with low inflammatory diet (via blood test)- Vitamin C
Timepoint [18] 369990 0
Baseline 6 months and just prior to surgery
Secondary outcome [19] 370077 0
Barriers and enablers to weight loss as assessed by thematic analysis of recorded & transcribed individual interviews and focus groups
Timepoint [19] 370077 0
When participants have been enrolled in the study for 6 months.

Key inclusion criteria
- Adults with osteoarthritis (OA)
- Body mass index (BMI) equal to or greater than 30
- Waitlisted for primary, unilateral or bilateral total knee or hip arthroplasty (TKA, THA)
- Ability to speak English, Arabic or Assyrian
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
- Unable to understand the protocol and thus provide informed consent
- Currently participating in fasting for religious or medical reasons.

Study design
Purpose of the study
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Not applicable
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?

The people analysing the results/data
Intervention assignment
Other design features
This a quasi-experimental pilot (feasibility) study.
A cohort who receive usual care will be prospectively recruited and followed.
After recruitment has completed for the usual care arm, a second cohort will be recruited and followed who will receive usual care plus access to a new dietary program.
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Analysis of the primary (feasibility) outcomes:

The criteria for assessing feasibility include:
i) < 1200 people required for a definitive trial from 2 sites; will be considered feasible);
ii) at least 60% of those eligible consent to the study
iii) improvement in the Medicul Food Frequency Questionnaire (FFQ) is greater in the intervention group (score is better in the intervention group);
iv) attendance at dietary consultations (study dietitian for intervention group; community-based dietitian for usual care) is > 50%
v) undertake blood tests at baseline and pre-surgery, >75%

If all five targets are reached, we will conclude the study is ‘definitely feasible’; if two to four are met, we will conclude the study is ‘feasible with modifications’. Failure to meet any of the targets will likely render a larger trial ‘not feasible’. We have set the targets lower than would be expected for the definitive trial as we expect protocol modifications (subsequent to the pilot and qualitative study) will improve these levels.

Analysis of secondary outcomes

For secondary outcomes, we will report the mean differences (95%CI) for continuous outcomes and Relative Risk (95%CI) for dichotomous outcomes. The primary outcome point will be the pre-surgery point (not 6 months) for most variables.
We will not do repeated measures analysis.
We will analyse using ITT and 'per protocol'

Dependent on resources, we will include a descriptive cost-analysis, detailing the patients’ total episode-of-care costs commencing the day of surgery and up to 90-days post-surgery. The staff costs of both programs will also be included. These data will help inform the planned cost-effectiveness analysis of the definitive study.

Stopping rules: We will undertake interim analyses after all participants complete 6-months of the program. If the proportion who have lost 5% or more body weight is not greater amongst those in the intensive program, we will consider early termination of the study. This is because if the two groups do not differ in their weight loss outcomes, there is no reason to expect different outcomes post-surgery based on differential weight loss. Based on existing data, we expect about 10-15% of patients participating in FOHKS to lose 5% or more body weight. At a minimum, weight loss of 5% is recognised as very achievable over a 6-month period in obese adults. We, therefore, require a minimum 20-30% of participants in the intensive program to lose 5% or more weight. In the event that the weight loss profile is not different between the groups, but there is a difference in inflammatory markers, the study may not be prematurely stopped. In other words, if those in the intensive low inflammatory diet group manifest lower level of inflammation as per their blood biomarkers, we would interpret this outcome an indicator of possible effectiveness.

Recruitment status
Active, not recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 13523 0
Fairfield Hospital - Prairiewood
Recruitment hospital [2] 13524 0
Campbelltown Hospital - Campbelltown
Recruitment postcode(s) [1] 26143 0
2176 - Prairiewood
Recruitment postcode(s) [2] 26144 0
2560 - Campbelltown

Funding & Sponsors
Funding source category [1] 302289 0
Name [1] 302289 0
Orthopaedic Department, Liverpool and Fairfield Hospitals
Address [1] 302289 0
Locked Bag 7103
Liverpool BC 1871
Country [1] 302289 0
Primary sponsor type
South West Sydney Local health District
Locked Bag 7103
Liverpool BC 1871
Secondary sponsor category [1] 302608 0
Name [1] 302608 0
Address [1] 302608 0
Country [1] 302608 0

Ethics approval
Ethics application status
Ethics committee name [1] 302966 0
South West Sydney Local Health District HREC
Ethics committee address [1] 302966 0
Liverpool Hospital
Locked bag 7103
Liverpool BC 1871
Ethics committee country [1] 302966 0
Date submitted for ethics approval [1] 302966 0
Approval date [1] 302966 0
Ethics approval number [1] 302966 0

Brief summary
- Obese people undergoing total knee or hip arthroplasty (replacement) surgery for osteoarthritis have worse outcomes (complications, less favourable longer-term recovery) compared to non-obese people.
- We hypothesise that a low inflammatory diet will be feasible and will encourage weight loss and will lower signs of inflammation in people with knee or hip arthritis awaiting joint replacement (arthroplasty).
- We will test our hypothesis using a quasi experimental study design [Before (control) and after (intervention) study].
- Little is known about barriers and enablers to weight loss ad a low inflammatory diet amongst obese people with end-satge arthritis and from culturally and linguistically diverse backgrounds. We aim to explore this through individual and focus group interviews.

Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 92006 0
A/Prof Justine Naylor
Address 92006 0
Orthopaedic Department
Liverpool Hospital
Locked Bag 7103
Liverpool BC 1871
Country 92006 0
Phone 92006 0
+61 2 8738 9253
Fax 92006 0
Email 92006 0
Contact person for public queries
Name 92007 0
A/Prof Justine Naylor
Address 92007 0
Orthopaedic Department
Liverpool Hospital
Locked Bag 7103
Liverpool BC 1871
Country 92007 0
Phone 92007 0
+61 2 8738 9253
Fax 92007 0
Email 92007 0
Contact person for scientific queries
Name 92008 0
A/Prof Justine Naylor
Address 92008 0
Orthopaedic Department
Liverpool Hospital
Locked Bag 7103
Liverpool BC 1871
Country 92008 0
Phone 92008 0
+61 2 8738 9253
Fax 92008 0
Email 92008 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
Any deidentified continuous data may be shared with researchers.
When will data be available (start and end dates)?
Data will only be available on request once the researchers have finished analysing the data and published the outcomes. The data will not be available 7 yrs after completion of the study (i.e after the last patients is followed up).
Available to whom?
Available for what types of analyses?
Meta- analyses
How or where can data be obtained?
Researchers will need to email the primary contact and provide a legitimate explanation and study protocol. The source of data will need to be acknowledged. Depending on the extent of data and work involved by the original investigators to provide and explain the data, the original investigators may reserve the right to be investigators on any study utilising the data.
What supporting documents are/will be available?
No other documents available
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary