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

Lower back pain is not an uncommon finding in obese and very obese individuals. One surgical treatment option is to create a fusion between two or more vertebrae in an attempt to reduce pain by stopping the motion at the painful vertebral segment(s).

In a paper just published in SPINE, Rahul Vaidya and colleagues from the Detroit Receiving Hospital and University Health Center, Detroit, report on their experience in a case series of 63 patients with a BMI of 30 or higher.

Despite a higher surgical risk and a 45% greater chance of complications, obese and very obese patients showed significant improvement in visual analog scale for back and leg pain with some improvement in disability scores independent of the BMI of the patient.

Thus, despite posing a greater challenge for the surgeon and slightly higher surgical risk, heavier patients stand to benefit as much from surgery as less obese patients.

Incidentally, as with other types of orthopedic surgeries that improve mobility, no “spontaneous” weight loss was found to occur after spinal surgery.

Important questions that remain to be answered include the role for pre-surgical weight loss and whether or not weight management will be made easier following surgery.

AMS
Edmonton, Alberta

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Victoria, BC

Last night I gave a talk to General Practitioners at the Medical School in Victoria, BC (hosted by Dr. Brad Amson, General/Bariatric Surgeon).

I spoke about the importance of carefully assessing patients for contributors and barriers to weight management.

As blogged yesterday, pain is one of the most common issues in patients with excess weight and can be both a contributor and barrier to weight gain and severely obese patients appear at particular risk for pain catastrophizing.

But how common is pain and how great is the incident risk in overweight and obese patients?

This issue was addressed in a recent study by Noor Heim and colleagues from the VU University, Amsterdam, The Netherlands, published in OBESITY.

This prospective study investigated the relationship between measured BMI and waist circumference with prevalent and incident pain in 2000 participants of the Longitudinal Aging Study Amsterdam, aged 55-85 years at baseline (1992-1993) and after after 3 years (N = 1,478) and 6 years (N = 1,271) of follow-up.

The overall prevalence of pain was 33% at baseline and increased significantly with higher quartiles of BM. After adjustment for age, education, depression, smoking, physical activity, and chronic diseases, both men and women in the highest quartile of BMI were around twice as likely to present with pain than individuals in the lowest BMI quartile.

Of the participants without pain at baseline, those in the highest quartile of BMI had a  2-fold increased odds for incident pain after 3 years of follow-up and around 2.5-fold after 6 years.

The association with BMI was independent of waist circumference, suggesting that absolute weight rather than weight distribution was important for pain.

This longitudinal study also answers the question whether or not pain in obesity is the chicken or the egg - it appears that obesity increases the risk for incident pain, rather than vice-versa.

But what about weight loss and its effect on pain? This issue, interestingly, has not been widely studied and results have been inconsistent. Apart from the rather dramatic improvement in pain and mobility reported in surgical obesity treatment, the effect of non-pharmacological or pharmacological weight loss on pain incidence or progression is not clear (though my guess is that weight loss can’t hurt - no pun intended).

Given the tendency of obese patients to catastrophize and the high incidence of depression and immobility, pain prevention and management is a key issue in the management of patients challenged by excess weight.

AMS
Victoria, BC

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Pain is one of the most common and debilitating problems in patients challenged by severe obesity. Not just a consequence of mechanical complications of obesity (osteoarthritis, back pain, plantar fasciitis, fibromyalgia, etc.), pain is often a key barrier to physical activity and thus weight management. In fact, excess pain can promote psychological (e.g. depression, anxiety) and behavioural (e.g. binge eating) factors that may further promote weight gain.

This issue is of even more importance in patients who display the now well-described phenomenon of pain catastrophizing, or the maladaptive responses to pain (tendency to focus on and magnify pain sensations with an intense sense of unbearable suffering and helplessness) that plays an extremely important role in how pain is perceived and processed. Pain catastrophizing now accounts for a substantial proportion of pain-related disability.

Studies in patients with fibromyalgia show that pain catastrophizing is associated with increased activity in brain areas related to anticipation of pain (medial frontal cortex, cerebellum), attention to pain (dorsal ACC, dorsolateral prefrontal cortex), emotional aspects of pain (claustrum, closely connected to amygdala) and motor control. Thus, catastrophizing influences pain perception through altering attention and anticipation, and heightening emotional responses to pain.

In another recent study by Tamara Somers and colleagues from Duke University, morbidly obese patients with osteoarthritis (OA) reported higher levels of pain catastrophizing than OA patients in the overweight and obese category. The severely obese patients who engaged in a high level of pain catastrophizing reported having much more intense and unpleasant pain, higher levels of binge eating, lower self-efficacy for controlling their eating and lower weight-related quality of life.

The relationship between pain catastrophizing and eating behaviour is of particular interest, as high-fat and high-sucrose foods have been shown to increase pain tolerance. Thus, binging on highly-palatable foods may be a compensatory response to emotional distress and pain. It is not difficult to see how patients can enter into a vicious cycle of pain, increased eating, weight gain, more pain, more eating, and so on.

In routine practice, pain catastrophizing can be easily and reliably assessed with questionnaires like this one, which can be scored like this.

Fortunately, pain catastrophizing is responsive to cognitive behavioural therapy, with clinically relevant improvements in upto 50% of individuals.

I would have little doubt that failure to recognize and address pain catastrophizing increases the likelihood of further weight gain and disability in patients with severe obesity.

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