Arya M. Sharma, MD

On most days, our obesity clinic could easily be confused with an orthopedic clinic given the sheer number of patients who present with severe pains in their backs, knees, hips, and ankles - often to the point of immobility.

It turns out (perhaps not surprisingly) that today, obesity and knee osteoarthritis are among the most frequent chronic conditions affecting Americans aged 50 to 84 years - my guess is that these conditions are no less frequent among Canadians.

Given the high prevalence of both obesity and knee osteoarthritis and their very significant impact on quality of life, Losina and a team of researchers from Harvard, Boston University, Chapel Hill, Yale and the University of Sydney undertook the rather momentous task of estimating the impact of these conditions on morbidity and mortality in older Americans. Their results were now published in the Annals of Internal Medicine.

The researchers based their analyses on U.S. Census and national obesity data with estimated prevalence of symptomatic knee osteoarthritis, whereby they assigned the US population aged 50 to 84 years to four subpopulations: nonobese without knee osteoarthritis (reference group), nonobese with knee osteoarthritis, obese without knee osteoarthritis, and obese with knee osteoarthritis.

They then used a computer simulation model (The Osteoarthritis Policy Model) to estimate quality-adjusted life-year losses due to knee osteoarthritis and obesity and to determine health benefits of reducing obesity prevalence to levels observed a decade ago.

It turns out that the estimated total losses of per-person quality-adjusted life-years ranged from around 2 years in nonobese persons with knee osteoarthritis to about 3.5 years for persons affected by both conditions. Although these numbers may not sound shocking, they actually represent 10% to 25% of the remaining quality-adjusted survival of persons aged 50 to 84 years.

When calculated for the entire US population in that age range, this amounts to a staggering 86 million quality-adjusted lost to these conditions.

The researchers also calculate that reversing obesity prevalence to levels seen 10 years ago would avert just over 110,000 total knee replacements - so reducing obesity (even to where it was just 10 years ago) could indeed save a substantial number of knees.

What the paper of course does not disclose is how exactly such a reversal in obesity rates could possibly be achieved.

Clearly, the impact of weight loss on knee (and other) pain that we see in our clinic is often dramatic, but achieving weight loss for someone who is already immobilised by knee (or other) pain is definitely a challenge.

I’d certainly love to hear from my readers on how knee (or other) pain has affected their weight and whether or not they have experienced improvement in their knee (or other) pain with weight loss.

AMS
Edmonton, Alberta

Losina E, Walensky RP, Reichmann WM, Holt HL, Gerlovin H, Solomon DH, Jordan JM, Hunter DJ, Suter LG, Weinstein AM, Paltiel AD, & Katz JN (2011). Impact of obesity and knee osteoarthritis on morbidity and mortality in older americans. Annals of internal medicine, 154 (4), 217-26 PMID: 21320937

Both osteoarthritis (OA) and metabolic syndrome (MetS) are associated with obesity and it may therefore not be unexpected to see increased prevalence of OA in patients with MetS and vice versa.

On the other hand, given the negative impact of OA on physical activity levels, it may also not be unreasonable to assume that individuals with OA may be more likely to present with weight gain and features of the MetS.

Finally, both OA and obesity have been associated with low levels of systemic inflammation, another factor that may promote metabolic abnormalities in these patients.

But how close is the relationship between OA and MetS in the general population?

This question was recently addressed by Rajitkanok Punepatom and colleagues from Chadds Ford, PA, in a paper just published in Postgraduate Medicine.

This study examined whether having OA predicts the presence of MetS in the National Health and Nutrition Examination Survey (NHANES) III, a representative sample of the general US population. The data set included 7714 subjects, of whom 975 subjects had OA.

Metabolic syndrome was present in 59% of the OA population and 23% of the population without OA with each of the 5 cardiovascular risk factors that comprise MetS being more prevalent in the OA population: hypertension (75% vs 38%), abdominal obesity (63% vs 38%), hyperglycemia (30% vs 13%), elevated triglycerides (47% vs 32%), and low high-density lipoprotein cholesterol (44% vs 38%).

The association between OA and MetS was strongest in younger subjects, where having OA at age 44 years was associated with an over 5-fold increased risk of MetS - a relationship that remained significant despite adjustment for body weight and other confounders.

This, not entirely unexpected association between OA and MetS, particularly in younger individuals, has a number of important clinical implications:

1) Cardiovascular risk factors should be routinely assessed and addressed in younger individuals presenting with OA.

2) Vice versa, assessment of joint health should perhaps be a routine part of assessment in younger patients presenting with signs of MetS.

3) It is likely that the common presentation of OA in patients presenting with MetS can be a significant barrier to increasing physical activity and weight management and therefore likely needs to be specifically addressed with appropriate physical and medical treatments.

AMS
Ottawa, Ontario

The musculoskeletal consequences of overweight and obesity are perhaps by far the most disabling and costly sequelae of excess weight. Although they may be less likely to kill you than heart disease or stroke (also consequences of obesity), obesity related pains in your muscle, bones and joints can reduce your quality of life to a level where having a heart attack may seem like taking the easy way out.

So what is the best conservative treatment for weight-related knee pain?

This question was addressed now in a randomised controlled trial published last month in the British Medical Journal. Specifically, Claire Jenkinson and colleagues from the University of Nottingham, UK examined the effects of dietary intervention and quadriceps strengthening exercises on pain and function in overweight people with knee pain.

The study was performed in five general practices in Nottingham and involved 389 men and women aged 45 and over with a body mass index equal or greater than 28.0 and self reported knee pain.

Participants were randomised to dietary intervention plus quadriceps strengthening exercises; dietary intervention alone; quadriceps strengthening exercises alone; or and advice leaflet only (control group).

Dietary intervention consisted of individualised healthy eating advice that would reduce normal intake by 600 kcal a day. Interventions were delivered at home visits over a two year period.

In the 289 (74%) participants who completed the trial, patients in the knee exercise groups reported greater reduction in knee pain than in the non-exercise groups at 24 months, although the effect size was moderate (number needed to treat for a 30% improvement in knee pain was 9).

As expected the dietary intervention group lost some weight (around 3 Kg), but this degree of weight loss did not have any meaningful effect on knee pain or function but was associated with a reduction in depression.

The authors conclude that a home based, self managed programme of simple knee strengthening exercises over a two year period can significantly reduce knee pain and improve knee function in overweight and obese people with knee pain.

Although a moderate sustained weight loss is achievable with dietary intervention and is associated with reduced depression, it is not enough to influence pain or function.

As knee pain is a common problem in patients presenting with excess weight, which if not addressed, will ultimately result in immobility and increasing weight gain, exercise prescriptions should be routinely implemented in patients presenting with this problem.

AMS
Edmonton, Alberta

Excess weight markedly increases the risk for a wide range of health problems including diabetes, heart disease, gall bladder stones, back pain, hip and knee problems and certain cancers. It is therefore reasonable to hypothesize that obesity is associated with increased need for hospitalization. This question is important because hospitalization accounts for a substantial proportion of health care costs.

Han and colleagues from the University of North Carolina, Chapel Hill, NC examined the relationship between obesity and hospitalization in the around 15,000 participants of the ARIC (Atherosclerosis Risk in Communities) Study, prospectively followed for 13 years - the results were published online in the International Journal of Obesity last week.

The study examined associations between weight status and all-cause and cause-specific hospitalizations (for cardiovascular and a few selected non-cardiovascular conditions). Analyses were adjusted for numerous factors including race, gender, age, physical activity, education level, smoking status, alcoholic beverage consumption and health insurance at baseline.

The average number of all-cause hospitalizations increased from 1316 per 1000 in normal weight individuals to 1543 in overweight and 2025 in obese participants. While normal weight women had significantly fewer hospitalizations than normal weight men (1173 versus 1515 per 1000), but the increase associated with being obese on the number of all-cause hospitalizations was larger in women than men (791 versus 589 per 1000).

While obesity was associated with increased hospitalization rates for all cardiovascular disease-related primary causes (e.g. myocardial infarction, congestive heart failure, stroke, etc.), the biggest relative impact of obesity was seen on hospitalization for osteoarthritis (9 per 1000 in normal weight vs. 79 per 1000 - an almost 8-fold increase!).

Based on this clear evidence that overweight and obesity substantially increases the number of hospitalizations, the authors emphasize that continued research on obesity treatment and prevention (I would add: as well as increasing access to obesity treatments) is essential.

AMS
Edmonton, Alberta

Yesterday, I came across a recent article on osteoarthirits by Simon Juang from the University of British Columbia, published in the latest issue of Parkhurst Exchange.

Given that osteoarthritis (OA) is probably the most common cause of pain and disability in patients with obesity, as a non-expert, I found the article most informative and relevant.

The following are some of the key pieces of information I gleaned from this overview:

First of all, I was surprised to learn that OA is not always painful, but on the other hand, that not all joint pain, simply because there may be radiological signs of OA, is actually due to OA. In fact, quite often the pain may result from the structures around the joint, i.e. the muslces, ligaments, tendons, bursae, osteophytes, injury, etc. As the course of treatment may well be different, proper diagnosis of the actual source of pain is essential.

The 4 pillars of OA management include:
- patient education
- non-pharmacological interventions
- drug therapy
- appropriate referral

The 4 goals of treatment are:
- reducing pain
- maintaining range and strength
- preserving function
- dercreasing the rate of progression

As expected, the basic joint health program starts with “optimal weight”, whereby however, Huang automatically assumes that this can be fixed by “proper diet”, best achieved by referral to a dietitian (readers of these pages will likely appreciate that if obesity management was indeed that simple, we would probably not have a crisis).

Other aspects of the joint program involve physiotherapists (exercises, heating pads, nerve stimulation, etc.), occupational therapists (activities of daily living), but also orthoticists, or podiatrists.

The article also lists a number of useful resources for patients, which I list here:

- The Athritis Society
- Arthritis Resource Guide for BC
- OASIS (OsteoArthritis Service Integrated System, Vancouver Coastal Health)
- Joint Health, Arthritis Consumer Experts
- Alberta Bone and Joint Institute
- Canadian Orthopedic Foundation

Remember, while managing pain and increasing mobility will not automatically result in weight loss, impaired mobility is certainly a major barrier to any weight management program.

AMS
Edmonton, Alberta