by Graham Peck
Reproduced with the permission of www.parkvets.com originally
featured in
the veterinary practice ezine published by www.vetsite.info.
X-Ray of a Canine's Spine and Femur
Osteoarthritis is the most common form of joint disease
found in both pets and humans. The resulting stiffness, pain
and loss of mobility can seriously degrade the affected individual's
quality of life. Treatment has classically involved the use
of anti-inflammatory drugs and surgery in advanced cases that
no longer can be medically managed.
Significant claims have been made for 'dietary supplements'
glucosamine and chondroitin as a treatment for osteoarthritis.
While some test results offer real promise, the full clinical
benefits of glucosamine and chondroitin have yet to be unequivocally
established by scientific trials. Despite this, enthusiastic
coverage in the popular media and even to some degree in the
medical press have engendered a public perception that glucosamine
and chondroitin are the new 'wonder treatment' for osteoarthritis.
This is a real concern. Many supplements are advocated as
useful in the management of common but challenging-to-treat
diseases. Inevitably commercial interests and unconditional
promotion will overstate the benefits that would be checked
by regulatory guidelines if the agent were classified as a
drug. The result is that the perceived benefits often far
exceed those established by scientific trials.
As always, our aim is to separate hyperbole from fact to
allow the reader to make an informed decision about what is
best for their pets and possibly also highly relevant to their
own health.
Osteoarthritis
Is a degenerative joint disease most usually associated with
'wear and tear'. Over time the normally smooth cartilage overlying
the ends of joint bones is gradually eroded. Exacerbating
factors can be trauma to the joints, obesity and strenuous
repetitive use. Although osteoarthritis is not always accompanied
by inflammation this is a common sign, as is joint pain, loss
of mobility and bony remodelling which many elderly pets and
owners will experience to some degree or other. These joint
changes typically progress with time and can become increasingly
debilitating to the affected individual.
Treatment of Osteoarthritis
Most conventional osteoarthritis treatment is palliative.
Their goal is to decrease the signs of pain and inflammation,
however they do little to address the underlying causes that
lead to progression of the disease.
Conventional therapies include:
1. Drugs
Typically nonsteroidal anti-inflammatory drugs (NSAIDs) and
corticosteroids.
NSAIDs are widely used and are effective in reducing clinical
signs. Unfortunately they are also associated with a high
rate of side effects including gastrointestinal ulceration
and kidney problems.
Corticosteroids can also be effective in alleviating signs
but similar concerns exist about side effects from long-term
use of these drugs.
2. Lifestyle management changes
Weight loss to correct obesity, dietary changes, carefully
managed exercise levels can have huge benefits for pets suffering
from osteoarthritis. Failure to address these issues will
frustrate management of the condition and allow progression
of the underlying disease process.
3. Surgery
A detailed discussion of surgery lies outside the remit of
this article. When pain related signs of an osteoarthritis
condition become unmanageable then surgery can enormously
improve the quality of life. Hip replacement in the dog is
an obvious example.
Slow-Acting Disease-Modifying Osteoarthritis Agents (SADMOGs)
These agents are believed to help reduce inflammation associated
with osteoarthritis plus slow the progression of the disease
and possibly promote cartilage synthesis.
In broad terms, osteoarthritis is where cartilage is broken
down faster than the body's can replace it. Laboratory studies
suggest that supplementation with glucosamine can stimulate
cartilage production while chrondroitin can inhibit enzymes
that breakdown or damage cartilage. It is suggested that the
net result is an increase in the amount of normal cartilage
slowing the progression of the osteoarthritis and reducing
signs of the disease.
Clinical studies in humans have shown that both glucosamine
and chrondoitin can relieve inflammation, pain and stiffness.
Also because both these substances are naturally manufactured
within the body far fewer side effects are seen compared to
NSAID's.
Other studies reported that pain scores decreased more quickly
for a NSAID compared to glucosamine and chrondoitin during
the first two weeks of treatment but after several weeks people
receiving the supplements were doing better than those receiving
NSAIDs.
Concerns about SADMOGs
While for the moment evidence suggests that these supplements
are safe and do reduce pain associated with osteoarthritis
some concerns do remain. A report by McAlidon et al in the
Journal of the American Medical Association examined research
from over three dozen studies on these supplements. While
agreeing that these studies showed positive effects, he raised
concerns over quality issues and likely publication bias (ie
publishing when you results agree with what you want but ditching
them when they don't). Because of this he felt that these
studies might well exaggerate the efficacy of these supplements.
Chard and Dieppe in the British Medical Journal felt this
latter point was even more likely because companies making
glucosamine and chrondoitin funded much of the reported research.
Dietary supplements are not subject to the same level of
regulation that ensures purity and quality as compounds classified
as drugs. This has resulted in large numbers of branded and
unbranded glucosamine and chrondoitin supplements now being
widely available over the counter, some of which are of questionable
quality. Independent laboratory analysis (consumerlab.com)
has shown that some of these products do not contain the amounts
of glucosamine and chrondoitin declared on the label.
There is also a significant cost associated with long term
medication using glucosamine and chrondoitin that raises the
issue of cost-effectiveness of the treatment. Especially if
the considerable sums spent on these supplements means that
other medical or surgical options cannot be afforded at a
later date.
Evidence of Efficacy
There is no shortage of anecdotal reports claiming that oral
glucosamine and chrondoitin alleviate the signs of joint pain
and stiffness in dogs plus improve mobility. Unfortunately
there is no scientific evidence that these supplements are
disease modifying for osteoarthritis in companion animals.
Most of the studies offered by manufacturers as evidence of
efficacy relate to human clinical trials.
Which formulation works best and the most appropriate dose
and route of administration are also unknown for companion
animals. The recommendations made by manufacturers again appear
to be extrapolated from the human data.
Safety
Glucosamine and chrondoitin appear to be safe as no serious
side effects have been reported however the minor side effect
of diarrhea was noted. There is a possibility that glucosamine
may worsen insulin resistance so patients with diabetes should
be monitored carefully. Chrondoitin should be avoided by patients
with bleeding disorders as it can aggravate these problems.
Summary
Unfortunately there is much uncritical and unsubstantiated
hype about these supplements. Anecdote and uncritical media
coverage have transformed this hype into what the public at
large now accept as 'fact' namely glucosamine and chrondoitin
can prevent and cure osteoarthritis.
In contrast the 'real facts' suggest that oral administered
glucosamine and chrondoitin may modify the clinical signs
of osteoarthritis in humans and possibly in companion animals.
Whether it actually can modify the progress of osteoarthritis
must await further large-scale clinical trials.
If these trials were successful in demonstrating the efficacy
of glucosamine and chrondoitin it will open up a whole new
area of management of osteoarthritis to the benefit of many
millions of people and pets. This would be welcomed by all
of us.
The important issue then, would be to establish which formulations
and doses are the most effective. Ideally one would want these
substances reclassified as drugs. This would ensure that quality
and efficacy issues would be fully addressed and that long-term
safety studies were also undertaken. Most importantly it would
protect pet owners and the public at large from the unscrupulous
people who in an unregulated market will sell substandard
products to trusting individuals.
Osteoarthritis and Supplements - Recommendations
If your pet starts to show signs of arthritis - (stiffness
and sore joints) consult your vet to get an expert diagnosis
before embarking on any form of treatment. While osteoarthritis
is common there are other serious joint problems that should
receive prompt attention.
Assess life style factors. Correcting obesity, modifying exercise
levels and undertaking non weight bearing exercise (swimming)
can often help resolve most of the signs of osteoarthritis
without any treatment in the early course of the disease.
If treatment is required discuss the pros and cons of NSAID's
with your vet. Often early on in the course of the disease
low doses at decreased intervals make be enough to manage
the signs.
Glucosamine and Chrondoitin
Where pets experience significant side effects from NSAID's
then it may be worth trying these supplements alone.
For some pets it may be possible to use lower levels of NSAID's
avoiding side effects by concurrently using glucosamine and
chrondoitin. Avoid using cheaper mail order supplements. Purity
and quality issues are best addressed by buying products recommended
by your veterinary surgeon.
Glucosamine and chrondoitin do take longer compared to other
anti-inflammatory drugs to produce an effect. If however after
a couple of months you can see no improvement in your pet
then have your vet re-evaluate the management of your pets
condition.
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Be sure to visit the Glucosamine Product Guide for a review of commercially available glucosamine products broken down by 9 different categories such as price per month, quality and type. Learn what the best products out there are and what criteria was used to ranked each.
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