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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
Type of registration
Prospectively registered

Titles & IDs
Public title
ADHERE study: Behaviour change SMS messages to promote longer term adherence to exercise for knee osteoarthritis.
Scientific title
ADHERE study: The effect of adding a behaviour change, short message service (SMS) intervention to a home based exercise program on exercise adherence in knee osteoarthritis and obesity.
Secondary ID [1] 289923 0
Universal Trial Number (UTN)
Trial acronym
Linked study record
Trial Id: ACTRN12617001013358

Health condition
Health condition(s) or problem(s) studied:
Osteoarthritis 299894 0
Condition category
Condition code
Musculoskeletal 299798 299798 0 0

Study type
Description of intervention(s) / exposure
Participants will be randomly allocated to either 1) SMS adherence intervention or 2) no adherence support control.

Participants in both groups will be expected to continue their home exercise program prescribed to them in a previous study, the TARGET study (Trial Id: ACTRN12617001013358). Participants will complete their prescribed home exercise program 3 times/week for 24 weeks. Each home exercise session will take approximately 20 minutes.

In addition participants in the SMS intervention will receive text messages over the 24 week period aiming to facilitate adherence to the home exercise program. Message content has been developed drawing on behaviour change theory and will address common barriers and facilitators to exercise participation previously identified in the knee OA literature. The messaging system will be automated, personalized using first names and be semi-interactive.

Participants will receive approximately 4-5 messages per week initially, dependent on their level of home exercise participation. At the start of the program all participants will receive 2 facilitator to exercise messages per week and a text message asking home many times they completed their home exercise program in the previous week. Participants who complete their home exercise program less than 3 times in the previous week will receive additional messages to identify and address the possible barriers to their exercise participation. Message frequency will gradually reduce over the 24 weeks, so as to not become burdensome to participants.

Participants in both groups will receive an optional exercise log book to record their weekly exercise practice over the 24 week period.
Intervention code [1] 295605 0
Intervention code [2] 298957 0
Comparator / control treatment
Participants in the control intervention will be expected to complete a home exercise program for their knee osteoarthritis 3 times per week for 24 weeks with no SMS support during that period.

Participants in the control intervention will also receive an optional exercise log book to use during the 24 week period.
Control group

Primary outcome [1] 299262 0
Self-reported number of exercise sessions in the last week (max 3)
Timepoint [1] 299262 0
24 weeks after baseline
Primary outcome [2] 299263 0
Exercise Adherence Rating Scale (EARS) Section B
Timepoint [2] 299263 0
24 weeks after baseline
Secondary outcome [1] 326679 0
Average overall knee pain in the previous week on an 11-point numeric rating scale
Timepoint [1] 326679 0
Baseline and 24 weeks after baseline
Secondary outcome [2] 326681 0
Knee Injury and Osteoarthritis Outcome Score (KOOS).
Pain sub-scale
Timepoint [2] 326681 0
Baseline and 24 weeks after baseline
Secondary outcome [3] 326682 0
Health related quality of life - AQoL2
Timepoint [3] 326682 0
Baseline and 24 weeks after baseline
Secondary outcome [4] 326683 0
Global change overall rated on a 7 point numeric scale from much worse to much better.
Timepoint [4] 326683 0
24 weeks
Secondary outcome [5] 335932 0
Physical Activity scale for the elderly (PASE)
Timepoint [5] 335932 0
Baseline and 24 weeks after baseline
Secondary outcome [6] 335933 0
Arthritis self-efficacy scale
Timepoint [6] 335933 0
Baseline and 24 weeks after baseline
Secondary outcome [7] 335934 0
Brief fear of movement scale
Timepoint [7] 335934 0
Baseline and 24 weeks after baseline
Secondary outcome [8] 335935 0
Pain Catastrophising Scale
Timepoint [8] 335935 0
Baseline and 24 weeks after baseline
Secondary outcome [9] 335937 0
Self-rated adherence to the home exercise program.
Scored on an 11-point Likert scale (0 – strongly disagree to 10 – strongly agree).
Timepoint [9] 335937 0
24 weeks after baseline
Secondary outcome [10] 338140 0
Knee Injury and Osteoarthritis Outcome Score (KOOS).
Function in Daily Living sub-scale
Timepoint [10] 338140 0
Baseline and 24 weeks after baseline
Secondary outcome [11] 338141 0
Knee Injury and Osteoarthritis Outcome Score (KOOS).
Other symptoms sub-scale
Timepoint [11] 338141 0
Baseline and 24 weeks after baseline
Secondary outcome [12] 338142 0
Knee Injury and Osteoarthritis Outcome Score (KOOS).
Function in sport and recreation sub-scale
Timepoint [12] 338142 0
Baseline and 24 weeks after baseline
Secondary outcome [13] 338143 0
Knee Injury and Osteoarthritis Outcome Score (KOOS).
Knee related quality of life sub-scale
Timepoint [13] 338143 0
Baseline and 24 weeks after baseline

Key inclusion criteria
Participants who complete a previous RCT (TARGET study, ACTRN 12617001013358) investigating the effect of two different exercise programs for people with medial knee osteoarthritis and obesity will be automatically enrolled into this trial.

The inclusion criteria for the previous RCT are;
I. aged 50 years and above;
II. report knee pain on most days of the past month;
III. suffered knee pain for 3 months or more;
IV. report a minimum average overall pain score of 4 on an 11-point numeric rating scale over the previous week
V. demonstrate tibiofemoral osteophytes on x-ray
VI. obesity (BMI of 30 kg/m2 and over)
VII. have a mobile phone that has text messaging functionality and be happy to receive text message reminders if required during the study
Minimum age
50 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
The exclusion criteria are;
I. Lateral joint space narrowing greater than or equal to medial joint space narrowing on x-ray;
II. knee surgery/joint injection in past 6 months or planned surgery in the next 9 months;
III. current or past (4 weeks) oral corticosteroids;
IV. systemic arthritic conditions;
V. past knee fracture or malignancy
VI. past hip/knee joint replacement/tibial osteotomy;
VII. other condition currently effecting lower limb function;
VIII. participation in knee strengthening or neuromuscular exercise in past 6 months or planning to start exercise in next 9 months;
IX. unable to walk unaided.
X. unable to commit to study requirements (Unable to attend study appointments or complete study

Study design
Purpose of the study
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
The person who determines if a participant is eligible for inclusion in the trial will be unaware, when this decision is made, to which group the subject will be allocated.
Randomisation will be concealed in a password protected computer database.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
This study will utilise participants completing another clinical trial, the TARGET study (ACTRN 12617001013358).

Computer generated randomisation will be prepared by our study biostatistician and will be conducted by permuted blocks of varying sizes, stratified by;
- exercise group assigned in the TARGET RCT (1. weight bearing functional exercise or 2.non-weight bearing quadriceps strengthening) and;
- baseline home exercise adherence in the previous week (Scale 0-4 where 0-1 = lower adherence; 2-4=higher adherence.) (Note: baseline home exercise adherence refers to home exercise adherence in the previous week, taken from the final time point of the TARGET RCT).

The randomisation schedule will be computer generated, using random permuted blocks of varying sizes. To conceal allocation, the randomisation schedule will be accessed via a password-protected, computer program by a researcher not involved in participant recruitment or assessment.
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Other design features
Not Applicable
Type of endpoint(s)
Statistical methods / analysis
Sample Size Calculation: Participants who complete the TARGET RCT will automatically and immediately be enrolled in the ADHERE RCT and randomised into one of two groups. Conservatively supposing that 102 participants (80% of the 128 TARGET enrolees) will be randomised into ADHERE, and that of those 102 participants, 80% will remain in ADHERE until week 24, this leaves 40 participants per group. With 40 participants per group, we will have 83% power to detect an effect size of 0.6 with two-sided significance level of 0.05, assuming a correlation between baseline home exercise adherence and home exercise adherence at 24 weeks of 0.4, including baseline home exercise adherence in the regression model as a covariate.

Statistical Analysis Plan: Analyses comparing the two groups will be performed by the statistician in a blinded fashion using all available data from all randomised participants. Demographic and baseline characteristics of participants at the time of randomisation in ADHERE will be summarised as appropriate (means and standard deviations for continuous variables that appear to be approximately normally distributed, medians and interquartile ranges for other continuous variables, counts and percentages for categorical variables) and will be inspected to assess baseline comparability of treatment groups. For continuous outcomes, differences in change will be compared between groups
using linear regression models adjusted for baseline levels of these outcomes and TARGET exercise group. Models for non-adherence outcomes will also contain a term for baseline home exercise adherence (a stratifying variable). Model assumptions will be assessed using standard diagnostic plots. For binary outcomes, differences between groups will be compared using relative risks, calculated from logistic regression models including terms for TARGET exercise group and baseline home exercise adherence. Should the amount of missing data for an outcome be such that imputation is required, multiple imputation will be conducted and the method reported.

Recruitment status
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)

Funding & Sponsors
Funding source category [1] 294287 0
Government body
Name [1] 294287 0
National Health and Medical Research Council (NHMRC)
Address [1] 294287 0
L 1 16 MARCUS CLARKE Street, Canberra Australian Capital Territory 2601
Country [1] 294287 0
Primary sponsor type
The University of Melbourne
1-100 Grattan Street, Melbourne, Victoria, 3010
Secondary sponsor category [1] 293127 0
Name [1] 293127 0
Address [1] 293127 0
Country [1] 293127 0

Ethics approval
Ethics application status
Ethics committee name [1] 295718 0
University of Melbourne Behavioural & Social Sciences (BSS-HESC)
Ethics committee address [1] 295718 0
University of Melbourne, Victoria, Australia, 3010
Ethics committee country [1] 295718 0
Date submitted for ethics approval [1] 295718 0
Approval date [1] 295718 0
Ethics approval number [1] 295718 0

Brief summary
Knee osteoarthritis (OA) is a major public health problem. Exercise is recommended by all clinical guidelines for managing pain in knee OA, however, effects of exercise on pain and function outcomes are only modest. This may be due to poor exercise adherence amongst knee OA sufferers. There is evidence that the use of text messaging as a behaviour change adherence tool can be effective in the healthcare setting for a variety of conditions. To date the use of SMS messages as an adherence tool for exercise has not been assessed in the knee OA population.
Our primary aim will therefore be to investigate the effects of adding a behaviour change embedded text message intervention, to a 6 month home based exercise program for knee osteoarthritis.
Participants who complete a previous RCT (ACTRN 12617001013358) will be randomly allocated to one of two groups:
i) SMS adherence intervention - a home based exercise program completed three times weekly for 24 weeks PLUS an automated, semi-personalised, mobile phone text message intervention, embedded in behaviour change theory to promote adherence to the exercise program.
ii) No adherence support control - a home based exercise program completed three times weekly for 24 weeks, independently with no adherence support.
Primary outcomes are self-reported adherence measures and secondary outcomes include self-reported pain and function. The primary timepoint is 24 weeks.

Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 68222 0
Prof Kim L Bennell
Address 68222 0
L7 161 Barry Street, The University of Melbourne, Victoria, Australia, 3010
Country 68222 0
Phone 68222 0
+61 3 8344 4135
Fax 68222 0
Email 68222 0
Contact person for public queries
Name 68223 0
Ms Sarah Schwartz
Address 68223 0
L7 161 Barry Street, The University of Melbourne, Victoria, Australia, 3010
Country 68223 0
Phone 68223 0
+61 3 8344 8455
Fax 68223 0
Email 68223 0
Contact person for scientific queries
Name 68224 0
Prof Kim L Bennell
Address 68224 0
L7 161 Barry Street, The University of Melbourne, Victoria, Australia, 3010
Country 68224 0
Phone 68224 0
+61 3 8344 9411
Fax 68224 0
Email 68224 0

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
What data in particular will be shared?
All of the individual participant data collected during the trial, after de-identification
When will data be available (start and end dates)?
Immediately following publication, no end date
Available to whom?
Case-by-case basis at the discretion of Primary Sponsor
Available for what types of analyses?
For IPD meta-analyses, etc.
How or where can data be obtained?
Access subject to approvals by Principal Investigator
What supporting documents are/will be available?
Informed consent form
Ethical approval
Summary results
No Results