Objectives
- Be able to outline/explain to patients benefits of weight loss on OA symptoms as per core clinical guidelines/evidence
- Be able to describe different interventions for weight loss and their efficacy according to key papers listed
- Be able to discuss weight management in an appropriate manner with patients
- Knowledge of weight and prognosis/risks of OA
How does obesity impact OA?
Important risk factor for developing OA-estimated to cause 25% of knee OA, and associated with progression of OA.
Not just through increase loads and biomechanical effects although has influence on these.
Load: every 1 kg of extra weight is extra 4kg load on knee joint. On the flipside for every 1kg lose, reduces load on knee by 4kg. Adipose tissue releases cytokines and adipokines, and levels are increased in obesity.
Some cytokines are associated with higher rates of OA and increased pain in knee OA. Other cytokines and adipokines have been associated with inflammation and matrix degradation and impairing cartilage repair.
Weight loss associated with reduction in inflammatory adipokines.
BUT-does potentially have an effect on load and cartilage-(Voinier et al., 2019) recent study looking at cartilage loss on MRI found patient with high BMI (>31kg/m2) and moderate (6000-7900) or high (>7900) daily steps had increased risk of cartilage loss over 2 year period compared with mid or low BMI and high step number.
On flip side, low BMI (18-27kg/m2) and low step number (<6000) also had increased risk of cartilage loss on MRI.
Obese patients at increased risk of post surgical complications following TKR-see Management options-surgical-TKR-subsections ‘comorbidities’ and ‘factors linked to poor outcome’
Being overweight or obese also has effects on general health and comorbidites such as diabetes, cardiovascular disease and life expectancy
A recent NSW study of nearly 24,000 people reported gaining weight increases risk of THR; whilst weight loss of >7.5% associated with reduced risk of TKR. (Jin, X., Gibson, A.A., Gale, J. et al. Does weight loss reduce the incidence of total knee and hip replacement for osteoarthritis?—A prospective cohort study among middle-aged and older adults with overweight or obesity. Int J Obes (2021). https://doi.org/10.1038/s41366-021-00832-3)
How much to lose?
Losing at least 5% of body weight can improve symptoms of knee OA; RACGP and OARSI guidelines recommend losing 5% over 20 weeks; aiming for 10% -greater improvements with more weight lost
If lose 5%of body weight pain decreases by 30% (about half people who takes NSAIDS get 30% reduction in pain).
If lose 10% of body weight essentailly doubles effect-over 50% reduction in pain, and improves self-efficacy and function. The more lost, the bigger the improvements, however biggest increment in improvement is with up to 10% body weight loss
How to lose weight?
Exercise alone does not seem to be enough to reduce weight, appears to require dietary change-with options including formula diet, group therapy and education.
Multicomponent lifestyle intervention (healthy eating plan, increased physical activity and support for behaviour change) is the first approach. More intensive interventions such as very low energy diets and medication can help some people to reduce weight further, and may assist in motivation to continue with lifestyle change towards longer term weight loss goals. Bariatric surgery is currently most effective intervention for severe obesity.
| BMI ≤27 | BMI 27-35 | BMI ≥35 | |
| First option | Lifestyle change:
-Increase physical activity as per guidelines
|
Lifestyle change:
-Increase physical activity as per guidelines
|
Lifestyle change:
-Increase physical activity as per guidelines
|
| Second option | Very low calorie diet/meal replacements | Very low calorie diet/meal replacements | |
| Third option | Medication e.g. Orlistat | Medication e.g. Orlistat | |
| Fourth option | Surgery |
For people with knee OA, combination of exercise and weight loss appears most effective (ADAPT and IDEA trials)-suggested exercise component of walk 15-20 minutes, session of strength training then another walk 15-20 minutes; 3 x week
Weight loss is complex with multiple factors-psycho-social, genetic, environmental, even government policy-also require to be aware of medical implications e.g. co-morbidity and wt loss such as diabetes and glucose levels and medication.
People often plateau at 7-8% loss of body weight
Physios are often aware of its importance but lack confidence to manage wt loss
Weight loss is challenging, and engaging patients with dietetics can also be challenging.
Common barriers include “I know what to do”, or “have been before and didn’t help”. Strategies that may help with patient engagement include suggesting dietetics can offer motivation and emotional support. Dietitians can potentially offer advice on specific diets such as anti-inflammatory diets that could be useful for reducing knee pain-although currently insufficient evidence to determine this conclusively.
Options for referral:
- Dietetics via EPC
- Community health services
- Private dietitians-including Healthy Weight for Life if have private health insurance at appropriate level
- If morbidly obese and have tried dietetics and other weight management strateiges previously, can consider referral for bariatric surgery via GP
There is increasing interest in the role of anti-inflammatory diets and the possible benefits of these for OA. An observational study of over 2000 people reported high intakes of total fat and saturated fatty acids may be associated with increased radiological OA progression, whereas higher intakes of mono and poly-unsaturated fatty acids may reduce radiographic progression (Lu et al 2016 https://doi.org/10.1002/acr.22952)
The traditional Mediterranean diet is characterized by a high intake of olive oil, fruits, nuts, vegetables, and cereals; moderate intake of fish and poultry; low intake of dairy products, red meat, processed meats, and sweets; and moderate intake of wine (ideally red).A US study reported the Mediterranean diet was associated with better quality of life and decreased pain, disability, and depressive symptoms in people with osteoarthritis (Veronese et al 2016 https://doi.org/10.3945/ajcn.116.136390)
A longitudinal study over a 4-year follow-up period for people with knee OA reported that higher adherence to Mediterranean diet is associated with a significantly lower risk of pain worsening and symptomatic knee OA, whilst no significant effect was observed on the incidence of radiographic knee OA. (Veronese et al 2019 https://doi.org/10.1016/j.clnu.2018.11.032)
Veronese, N., Koyanagi, A., , B., Cooper, C., Guglielmi, G., Rizzoli, R., Punzi, L., Rogoli, D., Caruso, M.G., Rotolo, O., Notarnicola, M., Al-Daghri, N., Smith, L., Reginster, J-Y., Maggi, S. (2019) Mediterranean diet and knee osteoarthritis outcomes: A longitudinal cohort study. Clinical Nutrition, Volume 38, Issue 6, Pages 2735-2739, ISSN 0261-5614,
https://doi.org/10.1016/j.clnu.2018.11.032.
Musculoskeletal Australia flyer on diet and OA
Australian Government Healthy Weight Guide
Health direct website information on weight loss BMI and waist circumference
Queensland Dept of Health Guide healthy eating and diet
App: myfitnesspal free to download and provides calorie counting, has list of foods can choose with calories calculated so don’t need to work out calories, also includes self entered exercise tracker