Plain English Summary
Background and study aims
Osteoarthritis is a condition that causes the joints to become painful and stiff. In the past few decades, research has identified the major risk factors for developing osteoarthritis of the knee. The next important step is to test preventive strategies in groups that are at high risk. Being overweight is the major modifiable risk factor for knee osteoarthritis. It is most often caused by unbalanced food intake in relation to physical activity, a way of life which is hard to change. To accomplish any change in such behaviour, a ‘tailor made’ diet and physical activity intervention is the most successful. However, an intervention with oral crystalline glucosamine sulphate, a chemical with growing scientific evidence for its joint-protective actions, is probably much easier and more feasible. In this study we will test the preventive effect of both interventions.
Who can participate?
Overweight women aged 50-60 (a high-risk group for knee osteoarthritis)
What does the study involve?
Participants are randomly allocated to either receive the tailor made weight loss intervention or to not receive this intervention. Secondly, in both groups half of the participants are randomly allocated to receive oral crystalline glucosamine sulphate while the other half receive a placebo (dummy drug). Both groups are followed for two and a half years. After two and a half years the occurrence of knee osteoarthritis is measured in both groups. After an additional 4-year observational period (i.e., 6.5 years after the start of the study), all available participants are re-evaluated.
What are the possible benefits and risks of participating?
Not provided at time of registration
Where is the study run from?
Afdeling Huisartsgeneeskunde (Netherlands)
When is the study starting and how long is it expected to run for?
December 2005 to April 2012
Who is funding the study?
Netherlands Organisation for Health Research and Development
Who is the main contact?
Jos Runhaar
j.runhaar@erasmusmc.nl
Trial website
Contact information
Type
Scientific
Primary contact
Mr Jos Runhaar
ORCID ID
Contact details
Department of General Practice
Room NA1906
PO Box 2040
Rotterdam
3000 CA
Netherlands
+31 (0)10 704 4192
j.runhaar@erasmusmc.nl
Additional identifiers
EudraCT number
ClinicalTrials.gov number
Protocol/serial number
NTR679
Study information
Scientific title
Prevention of knee Osteoarthritis in Overweight Females
Acronym
PROOF
Study hypothesis
Amended as of 03/12/2008:
In the present study we will test the preventive effect of a tailor made intervention for reducing weight as well as of an intervention with oral crystalline glucosamine sulphate in a factorial design in a high-risk group of overweight middle aged women who have not yet consulted for knee osteoarthritis. The positive outcomes with respect to feasibility of recruitement, compliance to the interventions, and low percentage of drop-out in the preceding feasibility trial led to the continuation of the study in this full-scale trial.
This trial was preceded by a feasibility trial with recruitment dates December 2005 – April 2007.
Initial information at time of registration:
The present study is a feasibility study. In this study, we will test the feasibility of the procedures used, the compliance to the interventions, and the usefulness of intermediate outcome measures in a specific high-risk group. If the results of this feasibility study are satisfactory, the project will be upgraded into a full scale preventive trial.
Ethics approval
Erasmus MC Medical Ethical Approval Commission, ref: 2005-231
Study design
Placebo-controlled 2 x 2 randomised factorial trial
Primary study design
Interventional
Secondary study design
Randomised controlled trial
Trial setting
GP practices
Trial type
Prevention
Patient information sheet
Not available in web format, please use the contact details to request a patient information sheet
Condition
Osteoarthritis in overweight females
Intervention
Patients are randomised for one of the following two interventions:
Intervention group A: a tailor-made intervention to reduce weight under the direction of dieticians of homecare, Rotterdam for one year
Control group A: the control group will not receive this active intervention to reduce weight
Intervention group B: daily supplementation with glucosamine sulphate (1500 mg per day) for one year
Control group B: the control group will receive a placebo
Intervention type
Mixed
Phase
Drug names
Primary outcome measure
Amended as of 03/12/2008:
Difference between intervention and control group in:
1. Occurrence of radiological knee OA (Kellgren and Lawrence index two or more), or
2. Joint space narrowing of 1 mm or more in one of the knees during follow-up time, or
3. Occurrence of knee OA according to the American College of Rheumatology (ACR) criteria
Initial information at time of registration:
1. Percentage of participants per group showing a reduction of 5 kg and/or 5% decrease at one year follow-up compared to baseline weight
2. Percentage of women compliant to the interventions in the study
3. Percentage lost to follow-up after one year
4. Percentage of eligible persons
Secondary outcome measures
Amended as of 03/12/2008:
Difference between intervention and control group in:
1. Quality of life (Euroqol)
2. Knee pain and knee function (WOMAC)
3. Actual weight loss
4. Occurrence of knee osteoarthritis seen on MRI (scoring according to the KOSS protocol for the presence of cartilaginous lesions, osteophytes, subchondral cysts, bone marrow oedema, for meniscal abnormalities, presence and size of effusion, synovitis and Baker's cysts)
5. Increase of bone and cartilage degradation markers
Initial information at time of registration:
1. Differences in intermediate outcomes between the intervention group A and control group A at one year follow-up
2. Differences in intermediate outcomes between intervention group B and control group B at one year follow-up
3. Change and variation in change in intermediate outcomes between baseline and one year follow-up.
Overall trial start date
01/12/2005
Overall trial end date
01/04/2012
Reason abandoned (if study stopped)
Eligibility
Participant inclusion criteria
Women aged 50 - 60 years who are overweight (body mass index [BMI] of 27 kg/m^2 or more)
Participant type
Patient
Age group
Adult
Gender
Female
Target number of participants
400
Total final enrolment
407
Participant exclusion criteria
Amended as of 03/12/2008: point six of the exclusion criteria has been amended as follows:
6. Contraindication for magnetic resonance (MR) imaging
Initial information at time of registration:
1. Knee osteoarthritis (OA)
2. Knee pain indicating knee OA
3. Radiological signs indicating knee OA (Kellgren-Lawrence index of 2 or more)
4. Positive for knee OA according to the American College of Rheumatology (ACR) criteria for knee OA
5. Presence of severe co-morbidity
6. Pacemaker
7. Current use of glucosamine sulphate
8. Not being able to communicate in the Dutch language
Recruitment start date
01/06/2008
Recruitment end date
01/05/2009
Locations
Countries of recruitment
Netherlands
Trial participating centre
Erasmus University Medical Center
Department of General Practice
PO Box 2040
Rotterdam
3000 CA
Netherlands
Sponsor information
Organisation
Erasmus Medical Centre (Netherlands)
Sponsor details
Department of General Practice
PO Box 2040
Rotterdam
3000 CA
Netherlands
Sponsor type
Hospital/treatment centre
Website
Funders
Funder type
Research organisation
Funder name
Netherlands Organisation for Health Research and Development
Alternative name(s)
Netherlands Organisation for Health Research and Development
Funding Body Type
private sector organisation
Funding Body Subtype
other non-profit
Location
Netherlands
Results and Publications
Publication and dissemination plan
Results of the first 2.5 years of the PROOF Study will be published from 2012 – 2015
Results of MRI data will be published from 2015 – 2017
Results of the complete follow-up time will be published from 2016 – 2017
Intention to publish date
Participant level data
Not expected to be available
Basic results (scientific)
Publication list
1. 2014 results in: http://www.ncbi.nlm.nih.gov/pubmed/23429925
2. 2014 results in: http://www.ncbi.nlm.nih.gov/pubmed/24774470
3. 2014 results in: http://www.ncbi.nlm.nih.gov/pubmed/24706992
4. 2014 results in: http://www.ncbi.nlm.nih.gov/pubmed/25278062
5. 2015 results in: http://www.ncbi.nlm.nih.gov/pubmed/25891749
6. 2015 results in: http://www.ncbi.nlm.nih.gov/pubmed/25818496
7. 2015 results in: http://www.ncbi.nlm.nih.gov/pubmed/26806185
8. 2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/27305950
9. 2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/26866630
10. 2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/26521011
11. 2016 results in: http://www.ncbi.nlm.nih.gov/pubmed/26748391
12. 2017 results in: http://www.ncbi.nlm.nih.gov/pubmed/28431145
13. 2019 results in: https://www.ncbi.nlm.nih.gov/pubmed/31300578 (added 15/07/2019)