Sunday, September 19, 2010

Dr. Cheney comments on a you-tube video made about his XMRV poster

Dr. Cheney comments on a you-tube video made about his XMRV poster


Dr. Paul Cheney has given me permission to post his comments about a
you-tube video that was made about his poster presentation at the recent
XMRV Workshop at the U.S. NIH earlier this month.  It's O.K. to repost these
comments, so long as they are attributed to Dr. Cheney.


Rich Van Konynenburg, Ph.D.
richvank@aol.com


"A poster presentation by me made at the 1st International XMRV meetings
held at the NIH in early September, 2010 was partially summarized by a
U-tube video (see
http://www.youtube.com/watch?v=gkgEQ...layer_embedded ).  While the video was
in many respects very well done and brings needed attention to CFS and its
link to XMRV, there are several errors and misrepresentations made about the
poster and what it actually said or implied.

"My biggest problem with this U-tube video was the emphasis on "heart
failure" as opposed to heart dysfunction or "LV diastolic dysfunction" which
predisposes to orthostatic intolerance rather than death by heart failure
which is very rare in my select cohort. My poster never said heart failure
was associated with CFS.  However, we do know that broadly defined diastolic
heart failure does not typically occur until age 72 or later so what will
happen to my patients when they get into their 70's is up in the air
,
assuming they are not treated with things like CSF's before then.  There is
also the semantic question of how heart failure is defined.  If it is
defined by organ failure and usually death within 5 years, I don't see this
and is likely very rare in the age brackets I see with CFS with an average
age of 49.  If it is defined by organ dysfunction including heart, GI tract,
exercise intolerance, heat intolerance and brain problems etc. produced by
low cardiac output then you could use the term heart failure due to
diastolic dysfunction in much of my practice.
  Death by such a functional
definition is, however, rare compared to the heart failure patients admitted
to hospitals with normal ejections fractions and deemed diastolic heart
failure.  Such a diagnosis is very lethal over the next five years with only
a third alive after five years and virtually all are quite disabled and will
remain so.

"Another problem is the "8 of 16 family members" positive for XMRV.  The
poster actually says 50% of healthy family controls or exposure controls
(N=8) were positive.  The U-tube video assumed that there were 8 positives
when in fact 8 were tested and 4 were positive.  6 of 8 were healthy family
members of CFS cases and 2 of 8 were CFS exposure controls and not family
members.  However, when we get the serology data back, I think the number of
family members infected will be higher than 50% and the N value will climb
well beyond 16 so this correction may soon be mute.

"I think the U-tube video misses the very important point that the cancer
rate is much higher (47%) in the non-CFS, first order family members than in
the CFS cases themselves.
  This will be the big story going forward as to
how you answer the question of why this is so.  Is CFS a compensatory
response to reduce serious disease and early death?  I will say that Dr.
Jason's assertion (or perhaps it is only the U-tube's assertion) that death
occurs 25 years before they should have died is a fallacy as that number is
drawn from the average age of all those who actually "died" and not a large
group of CFS cases.  In addition, perhaps a third of deaths occur by suicide
in the young CFS cases and that will skew that number of 25 years before
their time.

"The U-tube's final assertion that XMRV is a killer is somewhat exaggerated,
at least in CFS.  It certainly can be a killer but the U-tube video paints
the death rate as much higher than it really is in CFS.  In their defense,
XMRV is a killer but more-so in the non-CFS but infected cohort which I
think will be much larger than CFS itself and drives many cancers to be very
aggressive with much higher death rates than would otherwise occur (see
Singh et al, PNAS, 2009).  XMRV may also be driving the epidemic of
diastolic heart failure now seen in those over 70 and most die quickly
within five years once admitted to hospitals for heart failure (see Owan et
al, NEJM, 2006).  XMRV may well be a killer, but the paradox is that not as
much a killer in CFS unless perhaps they reach age 72 or above but that is
near our present human life expectancy.  The most interesting question of
all is how did they live that long with such a killer virus and with such
severe disability comparable to heart failure?"

Paul Cheney, M.D.
 


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