A retrospective, observational study evaluating the role of baseline BMI and weight loss in knee osteoarthritis: an audit of Osteoarthritis Healthy Weight For Life’s database

Presenter’s name (Last, First): Mcilwain, Elysse

Qualifications: BMedSc/BMedSc(Hons)/MBBS

Affiliations: John Hunter Hospital (Hunter New England Local Health District), Newcastle, Australia

Other authors:
Associate Professor David Dewar / OrthopaedicSurgeon / John Hunter Hospital. Dr Benjamin Wilcox / Orthopaedic Senior Resident Medical Office /John Hunter Hospital. Luke Lawler / BSc / Prima Health Solutions. Gareth Williams / B Teaching/BHealth & Physical Education / Honeysuckle Health. Dr Ryan Gallagher / PhD / Honeysuckle Health

Email: elysse.mcilwain@gmail.com

Background / Introduction:
Obesity contributes to the onset and progression of osteoarthritis and is associated with a 60% lifetime risk of developing knee osteoarthritis. With obesity rates increasing, so too will the burden of knee osteoarthritis. In 2020, 57.4% of knee arthroplasty patients were obese. Current literature suggests weight loss improves pain and function in knee osteoarthritis. This retrospective, observational study aims to evaluate if baseline BMI affects the improvement of knee pain/function associated with weight loss.

Patients / Methods:
Consecutive, non-selective participants of the Osteoarthritis Healthy Weight For Life (OA HWFL) program were included in the study. Participants of this remotely delivered 18-week weight-loss program had a BMI ≥28 with symptomatic knee osteoarthritis. Bodyweight and Knee injury and Osteoarthritis Outcome Score (KOOS) were collected for each participant at baseline and upon completion. Results were analysed to evaluate the effect of weight loss on pre and post program KOOS with respect to baseline BMI.


9004 Participants were enrolled in the program between January 2014 and July 2022. Of the 6360 with baseline and end of program KOOS data, 81% were obese at baseline with an average BMI of 34 (1179 Overweight, 2539 Obese Class 1, 1588 Obese Class 2 and 1054 Obese Class 3). The average weight loss across all baseline BMI categories was consistent ranging from 7.3%to 7.9%. The mean change in KOOS across all baseline BMI categories ranged from 13.4-14.1 for pain and 12.8-14.2 for function, with all mean KOOS change for each BMI category being statistically significant.

In our retrospective cohort, we demonstrated that weight loss at any baseline BMI resulted in a meaningful change in both knee pain and function. This promotes the encouragement in patients with BMI ≥28 with knee osteoarthritis, that weight loss can improve their knee pain and function, irrespective of baseline weight.

Level of Evidence & Study type: III Retrospective, observational study

Declarations of Conflict: Luke Lawler is the CEO of Prima Health Solutions (Prima) which is a fully owned subsidiary of Honeysuckle Health. Prima delivers the Healthy Weight for Life program. Dr Ryan Gallagher is a Clinical Insights Analyst employed by Honeysuckle Health. Gareth Williams is a Medical Specialist Relationship Manager employed by Honeysuckle Health. There is no commercial or financial relationship with any of the other investigators.