Weight Loss Intervention
Sustained weight loss is recommended to improve pain and function in overweight and obese patients with knee osteoarthritis.

Rationale

The Weight Loss Intervention recommendation has been downgraded one level because of inconsistent evidence.

There were 1 high (Jenkinson et.al 2009),1 moderate (Miller 2006), and 2 low strength (Focht 2005, Rejeski 2002) studies evaluating diet and exercise as weight loss interventions to treat knee osteoarthritis. Overall pain and function improved with weight loss achieved through a combination of diet and exercise.

 However, when evaluating only diet vs control, 2 high (Bliddal 2011, Christensen 2015), 2 moderate (Messier 2013, Mihalko 2018) and 2 low strength (Rejeski 2002, Fochyt 2005) there was no clear clinically significant change in patient outcomes. Specifically, Christensen et al, 2015 published a high-quality study investigating the effect of weight on symptoms of knee osteoarthritis.  They showed no significant difference in pain and function at 1 year. Bliddal et al, 2010 published another high quality study  which investigated the effect of weight loss on symptoms of knee OA in the obese patient, showing  that perceived pain (via WOMAC) was significantly lessened despite not being able to show improvement in function and quality of life at 1 year.

There were 2 moderate strength studies (Messier 2013, Mihalko 2018) which evaluated diet vs exercise, which favored exercises. To note, Messier et al  2013 published results of the IDEA trial with moderate quality study which was an attempt to determine if a 10% reduction in body weight (induced by diet, with or without exercise) would improve “clinical and mechanistic” outcomes in sedentary lifestyle patients (BMI 27 thru 41).  Interestingly, in this primary study, they were unable to show an improvement in WOMAC pain but they did show improvement in the WOMAC function subscale, and also showed improvements in the 6 minute walk test.

Given the current evidence, it is at the discretion of the surgeon as to which approach is utilized to address weight loss, however a combination of diet and exercises appears to be the preferred alternative.

Benefits/Harms of Implementation

There are no known or anticipated harms associated with implementing this recommendation.

Outcome Importance

Management of obesity and overweight through weight loss may have high impact on symptoms and overall health.

Cost Effectiveness/Resource Utilization

Weight loss presents a potentially high level of cost effectiveness compared to other surgical and nonsurgical approaches; however, the cost-effectiveness of different weight loss approaches is still to be determined.

Acceptability

Currently weight loss is a commonly utilized approach in the optimization of patient who present with obesity and knee osteoarthritis, hence there should be no issues implementing this recommendation as it does not influence a major change in clinical practice. To note, patients often are reluctant or unwilling to accept referrals for weight loss as a suggestion for a path to improvement.

Feasibility

This recommendation does not interfere with other interventions or clinical practice therefore it is deemed very feasible in a subset of overweight and obese patients.

Future Research

Future research should focus on large randomized clinical trials and should focus more on function and quality of life measures since it appears obvious that pain improved through weight loss.