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Trial registered on ANZCTR

Registration number

ACTRN12616000449437

Ethics application status

Approved

Date submitted

31/03/2016

Date registered

7/04/2016

Date last updated

10/07/2023

Date data sharing statement initially provided

10/07/2023

Date results information initially provided

10/07/2023

Type of registration

Prospectively registered

Titles & IDs

Public title

Effectiveness of a lumbo-pelvic monitor and feedback device to change postural behaviour in healthcare workers

Scientific title

The effectiveness of a lumbopelvic monitor and feedback device to change postural behaviour in healthcare workers with or without low back pain: a clustered randomized controlled trial

Secondary ID [1]

Nil known

Universal Trial Number (UTN)

U1111-1179-6611

Trial acronym

ELF Study

Linked study record

Health condition

Health condition(s) or problem(s) studied:

Low back pain

Condition category

Condition code

Musculoskeletal

Other muscular and skeletal disorders

Intervention/exposure

Study type

Interventional

Description of intervention(s) / exposure

Postural data will be recorded, and audio-feedback provided through a postural monitor feedback device. This device consists of a tri-axial accelerometer and data recorder, and has the size of a pager.

Data will be collected over a 6 week period and then at follow-up time points. During the first and sixth week, baseline and post-intervention measurements will be collected. The intervention period consists of 4 weeks (weeks 2 to 5, inclusive).
Arm 1 - Feedback Group (FG)
The FG will received postural audio-feedback, whenever the postural threshold is exceeded, during the four weeks of intervention. The field coordinator will be responsible for setting the devices and handing these to healthcare workers at the beginning of every week. Participants will wear the device clipped to their waistband or belt, during working hours, over the working days of each week.

To enhance adherence, workers will receive reminders to their mobile phones (if they consent with that), and reminders will be printed and placed at strategic areas of the workplace.

Adherence will be assessed as the number of days participants worked with the lumbopelvic monitor and feedback device, and was will be expressed as a percentage of total working days of that specific week.

Intervention code [1]

Behaviour

Intervention code [2]

Treatment: Devices

Comparator / control treatment

Participants allocated to the placebo group (PG) will not receive postural audio-feedback and the postural monitor and feedback will be adjusted to monitor and record the postural behaviour. The postural monitor and feedback device will be clipped on the waistband or belt, and will be worn during working hours, over the working days of each week data is collected.

Adherence will be assessed as the number of days participants worked with the lumbopelvic motion monitor, and was will be expressed as a percentage of total working days of that specific week.

Control group

Placebo

Outcomes

Primary outcome [1]

The primary outcome measure will be postural behaviour defined and expressed as the total number of times the postural threshold was exceeded in a week. Postural behaviour will be measured using a lumbopelvic monitor device.
Postural threshold was defined by setting threshold values for range of motion (45 degrees of lumbopelvic forward bending), frequency (a maximum of 2 lumbopelvic forward-bending events exceeding the range of motion threshold per minute), and duration of sustained bending (5 seconds).

Timepoint [1]

The baseline will occur at week 1. The follow-up will occur at the sixth week of data collection, and at one, three, six and twelve months after the sixth week. At baseline, and at the end of the sixth week, and the follow-up time points (one, three, six and twelve months), participants will wear daily the device during these weeks, so that postural behaviour can be monitored and recorded.

Secondary outcome [1]

Presence of low back pain over the course of follow-up (1 year), using the Delphi Definitions of Low Back Pain Prevalence (DOLBaPP) questionnaire

Timepoint [1]

Secondary outcome [2]

Functional disability, measured with the Oswestry Questionnaire and expressed in % of total score

Timepoint [2]

Secondary outcome [3]

Work-related psychosocial characteristics will be gathered by using the second short version of the second short version of the Copenhagen Psychosocial Questionnaire (COPSOQ II).

Timepoint [3]

At baseline participants will complete the second short version of the Copenhagen Psychosocial Questionnaire (COPSOQ II).

Secondary outcome [4]

Adherence will be assessed as the number of days participants worked with the lumbopelvic monitor and feedback device, and will be expressed as a percentage of total working days of each week of data collection.

Timepoint [4]

Baseline, Intervention period (weeks 2 to 5), Follow-up period (week 6, 1, 3, 6 and 12 months)

Eligibility

Key inclusion criteria

Adult healthcare workers, with or without LBP, presently performing their regular work activities, will be included.

Minimum age

18 Years

Maximum age

65 Years

Sex

Both males and females

Can healthy volunteers participate?

Yes

Key exclusion criteria

Participants who work less than 20 hours/week or are unable to undertake regular work-related activities due to LBP or any other musculoskeletal disorder will be excluded from this study.

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)

Randomization will be stratified by cluster-size (one to nine participants; or more than ten participants per centre). Within each strata, centres will be randomly assigned to one of the two groups (placebo or feedback group). To ensure allocation concealment, the investigator (JHA) will hold the randomization schedule, and will sequentially provide, by stratum, notification of group allocation to the recruiting investigator (JT) as each new site (cluster) is recruited.

Methods used to generate the sequence in which subjects will be randomised (sequence generation)

The randomization schedule will be generated using Randomization.com, a free online randomization program, by an investigator (JHA) not involved in recruitment, assessment, or statistical analysis.

Masking / blinding

Blinded (masking used)

Who is / are masked / blinded?

The people receiving the treatment/s

The people analysing the results/data

Intervention assignment

Parallel

Other design features

Blinding:

Participants will be blinded to group allocation. The researcher responsible for statistical analysis (DCR) will be blinded to group allocation until data analysis is complete. The field coordinator (JT) will be responsible for setting the postural monitor device, and delivering the devices to workers. This person will not be blinded to group allocation. The field coordinator will also be responsible for downloading the data from the postural monitor feedback device. Risk of bias is minimal as the primary outcome is measured and recorded by the postural monitor device, and secondary outcomes are participant self-reported.

Phase

Not Applicable

Type of endpoint/s

Efficacy

Statistical methods / analysis

Sample size estimation

The sample size is estimated based on the recommendations of Rutterford et al. [1]. We estimated the sample size for a standard RCT, using the ‘pwr’ package in R [2]. Assuming an effect size of 0.6 (identified through our published feasibility RCT) [3], alpha of 0.05, and power of 80% as input data for sample size calculation; a 2 arm RCT, with allocation ratio of 1:1, and one-tailed test appropriate to a superiority hypothesis, 35 subjects per group is the minimum required to achieve statistical significance level of 0.05 with power of 0.80. Assuming a 15% drop-out rate, a minimum of 40 participants per group will be required.

The sample size for the cluster RCT was estimated by, first, calculating the design effect (DE), using the following formula:

Equation 1: DE=1+[(1+CV^2 )m-1]p

Where:
CV = coefficient of variation of cluster size;
m = mean cluster size;
p = intracluster correlation coefficient.

Once the DE is calculated, sample size for the cluster RCT can be determined using Equation 2 [4]:

Equation 2: SS_Clustered = SS_RCT x DE

Where:
SS_Clustered = sample size for cluster RCT;
SS_RCT = sample size for standard RCT;
DE = design effect.

Equation 1 allows estimating sample size for a cluster RCT with unequal clusters sizes [4]. The CV is estimated by dividing the standard deviation of cluster size by the estimated mean cluster size [4]. The standard deviation of cluster size can be calculated by estimating the range of cluster sizes and dividing it by four [4]. For the purpose of this study, the estimated maximum cluster size is 15, and the estimated minimum cluster size is 5, which leads to a cluster size range of 10. The mean cluster size is assumed to be seven. The p was calculated based on data from the feasibility RCT, and was equal to 0.05. Based on Equation (1) and the values above described, the DE equalled 1.33. Therefore, using Equation (2), the estimated sample size for the cluster RCT was a minimum of 108 participants, with 15 clusters (approximately 7 participants per cluster).
The method we used (Equation 2) for estimating the DE tends to overestimate the sample size, and less conservative methods have been described in the literature [1, 5]. We opted for a conservative estimation of the DE because our feasibility RCT may have inflated the true effect size for the intervention [6].

Statistical analyses
All statistical analyses will be performed using R software [7]. Intention-to-treat analysis will be performed to estimate the effect of feedback provision on postural behaviour. For all statistical analysis, alpha will be set at 0.05. Missing data will be dealt with by using maximum likelihood estimation [8].

1) Study Aim 1
All statistical analysis will be conducted using R [7]. The use of cluster randomization reduces statistical power [1], so we will compensate power loss by increasing precision through adjustment for covariates (i.e. demographic data, baseline measurements; functional disability, measured with the Oswestry Disability Index; and psychosocial factors, measured with COPSOQII) in the statistical analysis [1, 5]. All statistical analyses will be conducted using individual level data.

Two repeated measures mixed-effect model analysis of variance (ANOVA) will used for assessing (1) within-group and (2) between-group changes in postural behaviour. The difference between the two models is that the ‘time point’ factor will include baseline measurements for the within-group comparison. This will allow us to assess the within-group immediate changes in postural behaviour at the 6th week. For the between-group comparison, baseline measurements will be controlled for and considered as a covariate. Therefore, baseline measurements will be removed from the ‘time point’ factor.

1.1) Within-group comparisons
Postural behaviour scores (as measured by the postural monitor and feedback device) will be used as dependent variable; participants and clusters will be considered as random-effects; and follow-up time points (baseline, 6th week, one, three, six and twelve months), postural behaviour baseline scores, work-related psychosocial factors and ODI scores will be considered as fixed-effects. Significant interactions and main effects will be followed-up with planned contrasts, with alpha adjusted for multiple comparisons [9].

1.2) Between-group comparisons
Postural behaviour scores (as measured by the postural monitor and feedback device) will be used as dependent variables; participants and clusters will be considered as random-effects; and follow-up time points (6th week, one, three, six and twelve months), baseline postural scores, work-related psychosocial factors and ODI scores will be considered as fixed-effects. “Time point x intervention” interaction will be included in the model. Significant interactions and main effects will be followed-up with planned contrasts, with alpha adjusted for multiple comparisons [9].

2) Study Aim 2
Research question 2 is a secondary analysis, and findings related to this research question will be submitted for publication as a separate manuscript. The primary outcome measures for research question 2 are low back pain disability scores and presence of low back pain.

2.1) The effect of postural feedback intervention on low back pain disability scores
Low back pain disability scores, as measured with the Oswestry Disability Index questionnaire (ODI), will be used as the dependent variable; participants and clusters will be considered as random-effects; and follow-up time points (6th week, one, three, six and twelve months), baseline ODI, and work-related psychosocial factors will be considered as fixed-effects. “Time point x intervention” interaction will be included in the model. Significant interactions and main effects will be followed-up with planned contrasts, with alpha adjusted for multiple comparisons [9].

2.2) Time to LBP resolution in participants presenting LBP at baseline, and time to developing LBP in participants who are symptom free at baseline
A discrete time to event (survival) analyses will be used to assess the time to LBP resolution and time to developing LBP using logistic regression. We will consider the effects of baseline measurements (i.e., age, body mass index, smoking habits, postural pattern at baseline, psychosocial factors, and Oswestry scores) and intervention group (i.e., control or feedback group) on time to LBP resolution for those who have LBP, and time to developing LBP on symptom free participants. Unadjusted survival analyses will be conducted using the demographic ad intervention effects on the resolution of or development of LBP. If numbers permit, adjusted models will be explored. Kaplan-Meier analyses will assess ‘discrete time survival’ between the groups for both time to LBP resolution and time to developing LBP. Survival curves will be constructed based on follow-up time-points, proportional hazards models will be used to assess the hazard ratios (HR) for each intervention group (i.e., control and feedback group) [10], and the HRs and their respective 95% confidence intervals and p-values will be reported.

References
1. Rutterford, C., A. Copas, and S. Eldridge, Methods for sample size determination in cluster randomized trials. Int J Epidemiol, 2015. 44(3): p. 1051-67.
2. Stephane Champely, S., et al. Basic Functions for Power Analysis. 2015 [cited 2015 20/01/2016]; Available from: https://cran.r-project.org/web/packages/pwr/pwr.pdf.
3. Ribeiro, D.C., et al., The effectiveness of a lumbopelvic monitor and feedback device to change postural behavior: a feasibility randomized controlled trial. J Orthop Sports Phys Ther, 2014. 44(9): p. 702-11.
4. Eldridge, S.M., D. Ashby, and S. Kerry, Sample size for cluster randomized trials: effect of coefficient of variation of cluster size and analysis method. Int J Epidemiol, 2006. 35(5): p. 1292-300.
5. van Breukelen, G.J. and M.J. Candel, Calculating sample sizes for cluster randomized trials: we can keep it simple and efficient! J Clin Epidemiol, 2012. 65(11): p. 1212-8.
6. Teare, M.D., et al., Sample size requirements to estimate key design parameters from external pilot randomised controlled trials: a simulation study. Trials, 2014. 15: p. 264.
7. R_Core_Team. R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna, Austria. ISBN 3-900051-07-0, URL http://www.R-project.org. 2008 [cited 2011 01/03/2011]; Available from: http://www.R-project.org.
8. Diaz-Ordaz, K., et al., Are missing data adequately handled in cluster randomised trials? A systematic review and guidelines. Clin Trials, 2014. 11(5): p. 590-600.
9. Field, A., Discovering statistics using R. 1 ed. 2012: SAGE Publications Ltd.
10. Spruance, S.L., et al., Hazard ratio in clinical trials. Antimicrob Agents Chemother, 2004. 48(8): p. 2787-92.

Recruitment

Recruitment status

Completed

Date of first participant enrolment

Anticipated

13/04/2016

Actual

28/04/2016

Date of last participant enrolment

Anticipated

Actual

1/04/2017

Date of last data collection

Anticipated

Actual

22/04/2018

Sample size

Target

108

Accrual to date

Final

130

Recruitment outside Australia

Country [1]

New Zealand

State/province [1]

Otago

Funding & Sponsors

Funding source category [1]

Government body

Name [1]

Health Research Council

Address [1]

Level 3 - ProCARE Building, Grafton Mews, at 110 Stanley Street, Auckland
Postcode: 1010
PO Box 5541, Wellesley Street, Auckland 1141

Country [1]

New Zealand

Funding source category [2]

Government body

Name [2]

Lottery Health Research

Address [2]

The Department of Internal Affairs
46 Waring Taylor Street
WELLINGTON
Postcode: 6011
PO Box 805
WELLINGTON 6140

Country [2]

New Zealand

Primary sponsor type

University

Name

University of Otago

Address

325 Great King Street,
Postcode: 9054
PO Box 56
Dunedin

Country

New Zealand

Secondary sponsor category [1]

None

Name [1]

Address [1]

Country [1]

Ethics approval

Ethics application status

Approved

Ethics committee name [1]

University of Otago Ethics Committee

Ethics committee address [1]

University of Otago Council PO Box 56 Dunedin 9054 New Zealand

Ethics committee country [1]

New Zealand

Date submitted for ethics approval [1]

21/09/2015

Approval date [1]

22/01/2016

Ethics approval number [1]

H15/094

Summary

Brief summary

The study will assess whether a postural monitor and feedback device can help workers to prevent hazardous posture at the workplace.
It is hypothesized that workers exposed to the feedback intervention will change their postural behaviour and reduce the amount of time spent in flexed posture at the workplace.

Trial website

Trial related presentations / publications

Public notes

Contacts

Principal investigator

Name

Dr Daniel Cury Ribeiro

Address

School of Physiotherapy - University of Otago 325 Great King Street, Postcode: 9054, PO Box 56, Dunedin

Country

New Zealand

Phone

+64 3 4797455

Fax

[email protected]

Contact person for public queries

Name

Daniel Cury Ribeiro

Address

School of Physiotherapy - University of Otago 325 Great King Street, Postcode: 9054, PO Box 56, Dunedin

Country

New Zealand

Phone

+64 3 479 7455

Fax

[email protected]

Contact person for scientific queries

Name

Daniel Cury Ribeiro

Address

School of Physiotherapy - University of Otago 325 Great King Street, Postcode: 9054, PO Box 56, Dunedin

Country

New Zealand

Phone

+64 3 4797455

Fax

[email protected]

Data sharing statement

Will individual participant data (IPD) for this trial be available (including data dictionaries)?

Yes

What data in particular will be shared?

Primary outcome measure.

When will data be available (start and end dates)?

2022.
No end date determined.

Available to whom?

Only researchers who provide a methodologically sound proposal.

Available for what types of analyses?

To achieve the aims in the approved proposal or for IPD meta-analyses.

How or where can data be obtained?

Access subject to approvals by Principal Investigator ([email protected])

What supporting documents are/will be available?

Doc. No.	Type	Citation	Link	Email	Other Details	Attachment
19645	Study protocol	Ribeiro DC, Milosavljevic S, Abbott JHEffectiveness of a lumbopelvic monitor and feedback device to change postural behaviour: a protocol for the ELF cluster randomised controlled trialBMJ Open 2017;7:e015568. doi: 10.1136/bmjopen-2016-015568	https://bmjopen.bmj.com/content/7/1/e015568

Results publications and other study-related documents

Documents added manually

Type	Is Peer Reviewed?	DOI	Citations or Other Details	Attachment
Study results article	Yes		Occupational and Environmental Medicine, 2020, 77 ... [More Details]

Documents added automatically

Source	Title	Year of Publication	DOI
Embase	Effectiveness of a lumbopelvic monitor and feedback device to change postural behaviour: A protocol for the ELF cluster randomised controlled trial.	2017	https://dx.doi.org/10.1136/bmjopen-2016-015568

N.B. These documents automatically identified may not have been verified by the study sponsor.

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