Effects of a Physiotherapist-delivered Dietary Weight Loss Program in People With Knee OA Who Have Overweight/Obesity
Condition: Knee Osteoarthritis; Overweight and Obesity
MeSH terms: Osteoarthritis; Osteoarthritis, Knee; Obesity; Overweight; Weight Loss
Study type: Interventional

Summary: 
      The aim of this randomized controlled trial is to evaluate the effects of a
      physiotherapist-delivered dietary weight loss program on clinical outcomes among people with
      knee osteoarthritis (OA) who have overweight or obesity. The primary hypothesis is that a
      physiotherapist-delivered dietary weight loss plus exercise program will be more effective in
      achieving weight loss than a physiotherapist-delivered exercise program alone. Approximately
      6-9 physiotherapists in Melbourne, Australia will be recruited and trained in weight
      management for OA patients, as well as trained in how to deliver the specific study
      interventions. The same therapists will deliver the intervention in both arms of the trial.
      88 participants with knee OA will be recruited from the community and randomized into one of
      the two arms a) diet plus exercise intervention or b) exercise intervention alone.
      Participants in both groups will be asked to attend 6 consultations with the physiotherapist
      over 6 months. Questionnaire and laboratory-based outcome measures will be completed by
      participants at baseline and at the end of the 6 month intervention period. A biostatistician
      will analyse blinded, de-identified data.
    

Detailed description: 
      Clinical guidelines for the management of knee OA recommend exercise as a core treatment for
      all patients as well as losing weight for those patients who also have overweight/obesity.
      However, health care systems are frequently under strain often experiencing limited numbers
      of, and access to, clinicians with specialist weight loss and health behavior change skills.
      New models of care for OA are needed that support expanded practice roles for clinicians.
      Physiotherapists are key providers of exercise therapy for knee OA but the effectiveness of
      physiotherapists to deliver a dietary weight loss program for patients with knee OA is not
      known.

      This study is a randomized controlled trial for which the aim is to evaluate the effects of a
      physiotherapist-delivered dietary weight loss program in addition to exercise, on weight loss
      and other clinical outcomes among people with knee OA who have overweight or obesity. The
      research question is: Is a 6-month physiotherapist-delivered dietary weight loss plus
      exercise program more effective for improving clinical outcomes than a
      physiotherapist-delivered exercise program alone in people with knee OA who have overweight
      or obesity?

      Clinical practice guidelines for knee OA recommend patients who have overweight or obesity
      should lose at least 5-7.5% of body weight. Therefore the study is powered to detect a
      conservative between-group difference in weight loss of 5% of body weight assuming no change
      in weight in the control group (exercise only) based on previous research.

      A total of 88 participants with chronic knee pain and a clinical diagnosis of knee OA will be
      recruited from the community. Participants will be enrolled into the study following informed
      consent and completion of baseline questionnaires and laboratory-based measures. Each
      participant will be randomly allocated to receive a: a) diet plus exercise program or; b)
      exercise program alone, over 6 months.

      The randomization schedule will be computer generated and prepared by the biostatistician
      (permuted block sizes 6 to 12) stratified by physiotherapist and sex of participant. The
      schedule will be stored on a password-protected website maintained by a researcher not
      involved in either participant recruitment or administration of outcome measures. Group
      allocation will be revealed to the physiotherapists and the participants by this same
      researcher following randomisation.

      The physiotherapists will undertake comprehensive training prior to being allocated trial
      participants. Physiotherapists will be trained in weight management, the ketogenic very low
      calorie diet and trial procedures.

      Study participants in both groups will visit a physiotherapist in-person for six individual
      sessions over 6 months. Participants will choose the therapist according to location. The
      same therapist will undertake all consultations with any given participant.

      Those in the diet plus exercise group will undertake a ketogenic very low calorie diet (VLCD)
      which has been demonstrated as a safe and effective means of achieving rapid weight loss in
      the adult population with overweight/obesity. They will receive meal replacements (maximum 2
      per day) for up to 14 weeks from the start of the study as well as educational resources.
      Both groups will also undertake a home-based lower limb muscle strengthening exercise and
      physical activity program.

      A biostatistician will analyse blinded data. Comparative analyses between groups will use
      intention-to-treat. Multiple imputation will be used to account for missing data if the
      proportion of missing data is >5%. For the primary outcome, the difference in mean percentage
      change in body weight will be compared between groups using mixed linear regression model
      adjusting for baseline weight and the stratification variables, with random intercepts for
      treating physiotherapist. Similar analyses will be conducted for continuous secondary
      outcomes. We will also calculate the proportion of participants achieving ≥5% and ≥10% loss
      of body weight in both groups. For binary outcomes, logistic regression models will be fit
      using generalized estimating equations, with risk differences and 95% confidence intervals
      calculated.
    

Intervention name(s): Diet plus exercise; Exercise
Intervention type(s): Other; Other
Intervention description(s): The diet program has two phases: 1) intensive weight loss through a ketogenic very low calorie diet VLCD, and 2) transition from ketogenic VLCD onto a healthy eating plan for weight maintenance. Meal replacements will be provided to participants free of charge from the start of the trial to a maximum of 14 weeks (12 weeks for the ketogenic diet and 2 weeks for transition). If a participant does not wish to transition off the ketogenic diet after 14 weeks but wants to continue or if they wish to recommence the ketogenic diet any time after week 14 they will need to purchase meal replacements themselves at their own cost.
Participants will be encouraged to aim to lose at least 10% body weight.; The trial coordinator will have provided participants with educational material about OA, handouts of home exercises including photographs and descriptions, a logbook for recording home program completion and resistance exercise bands ahead of their first appointment. Physiotherapists will prescribe 5-6 strengthening exercises from a pre-determined list to be performed at home three times/week, including two quadriceps exercises, one each for hip abductors, hamstrings and calf, and any other as appropriate. Review and modification will occur at each consultation to maintain moderate intensity (effort of ≥5 out of 10 (hard) on a modified Borg Rating of Perceived Exertion scale). The physiotherapist will also prescribe a personalised physical activity plan in collaboration with the participant that is supported and progressed over time.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Investigator, Outcomes Assessor)
Primary purpose: Treatment