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JAMA Article

Posted by Tony on 9/22/02 at 18:38 (095976)

The JAMA article draws several conclusions that are
different from the previous double blind studies on
ESWT. It has been argued that their results were
caused by treating all patients with ESWT. However,
I think that there are other factors in their study
that could equally explain their results.

1. Half of the actively treated patients had symptoms
for less than 6 months. It is my understanding that 90%
of patients with PF respond to conservative therapy.
The previous studies required 6 months of failed
conservative therapy and were conducted on patients with
a mean symptoms of 22 months. We could predict a priori that
90% of the patients in the JAMA study would get better because
they should respond to conservative therapy since they had symptoms
for less than 6 months. The JAMA study simply did not have
enough subjects that failed conservative therapy to factor
out this natural conclusion.

2. The blinding of the study is suspect. The actively treated
group was treated to pain tolerance. However the authors
reported that only 24% of the actively treated patients
correctly guessed that they were treated. I have a hard time
believing that patients that perceived treatment pain would
not guess that they were actively treated. It just seems that
a study participant would associate treatment pain with treatment
and not placebo. We know that there is a strong placebo effect.
This means that most of the actively treated patients believed that
they did not receive treatment. Could this have resulted in lower
scores for these patients?

3. The amount of energy delivered to the actively treated group
varied widely. On page 1368 the authors report that 13 actively
treated patients received less than 1000mJ/mm2 and that 68 received
over 1000mJ/mm2. This level of energy was delivered over three
treatments. In the Dornier PMA submitted to the FDA, all
patients received 1300mJ/mm2 in one treatment. We cannot know
if the JAMA study's results were affected by the varying amount of
energy delivered over the three treatments.

First, patients with the lowest pain tolerance received the least
amount of power. On average, these patients received 40% less
treatment energy than patients with higher pain tolerance. Did
this cause their treatment to fail?

Second, there is no evidence that three treatments at low power
add up to one treatment at high power. There have been no studies
that look at several low power treatments vs on high power treatment.
The authors have no basis to correlate the results of their study to
the results of a study with high power treatments.

Finally, the authors do not adequately discuss the variability
between power level delivered to different patients and outcome.
They do not even discuss the differences between actively treated
patients that received 2000 shocks per treatment and others
received 2500 shocks per treatment.

I think that the JAMA article raises questions about the use of low
power ESWT as a first line treatment in PF. I do not think it
adequately disputes the previous studies since there is no reasonable
connection between low power treatments and high power treatments.
For example, do the authors believe that 1000 treatments at 1 mJ/mm2
would have the same treatment effect at 1 treatment at 1000 mJ/mms?

I think that the authors have concluded too much from their study.
Just my opinion so take it for what its worth. I am not a podiatrist
but I am interested in ESWT.

I'd like to hear other people's opinions about this article.

Re: JAMA Article

Dr. Z on 9/22/02 at 19:10 (095978)

Hi Tony

Very good observations. I could write an entire book on this study and its lack of good scientiful protocol. The three main observation are the following

1. This was a low energy multiple session study with total mj's of 1000

2. No standard control was used A control can use have treatment of any kind. The FDA control had no active treatment

3. The duration of pain was at least six weeks. The FDA study was two years

4. No one ever treats pf with pain duration of six weeks

5. The AMA study allowed patients to contiune with orthosis, pain meds and orthosis. There was complete discontinuation of any type of treatment post FDA dornier study

There is alot more but this is enougt

Re: JAMA Article

Dr. Z on 9/22/02 at 19:10 (095978)

Hi Tony

Very good observations. I could write an entire book on this study and its lack of good scientiful protocol. The three main observation are the following

1. This was a low energy multiple session study with total mj's of 1000

2. No standard control was used A control can use have treatment of any kind. The FDA control had no active treatment

3. The duration of pain was at least six weeks. The FDA study was two years

4. No one ever treats pf with pain duration of six weeks

5. The AMA study allowed patients to contiune with orthosis, pain meds and orthosis. There was complete discontinuation of any type of treatment post FDA dornier study

There is alot more but this is enougt