Tom Kindlon's Written Testimony: CFSAC Meeting May 2009
My name is Tom Kindlon. I have CFS for over 20 years, having previously
been healthy (and very "sporty"). Unfortunately it took me over 5 years to
get diagnosed. By the time I was diagnosed I was virtually bedbound and I
have only improved a small bit since then i.e. I have been housebound with
CFS for nearly 15 years.
Before my CFS deteriorated, I was studying Mathematical Sciences in Trinity
College Dublin (I got straight Firsts in the last year I did there - second
year exams) so have some knowledge of mathematical and statistical
I have been on the committee of the Irish ME/CFS Association (formerly the
Irish ME/CFS Support Group) since 1996 and have been Assistant Chairperson
since 1997. Amongst other things, I have helped organise the Association's
response to thousands of enquiries in that period and have talked with
hundreds of people with the condition. I have also been on Internet CFS
forums since 1995 and thus heard people from around their world describe
their illness and the effect it has had on them, as well as participating in
many interesting discussions. I believe I have a lot of useful knowledge
and experience in the area. In the last twelve months, I have had two
letters on the subject of CFS published in Pubmed-listed journals.
I am very concerned about the "empirical" definition (Reeves, 2005) the CDC
has adopted for CFS research in recent years.
I have posted numerous online comments to papers relating to the definition
but the CDC has never responded to any of the points.
Frustrated by the CDC's continued use of the definition, I set up a petition
on the issue on the 15th of April, 2009 (i.e. last month). This petition is
summarized in 10 words as,
"CDC CFS Research should not involved the empirical definition (2005)"
We call on the Centers for Disease Control and Prevention (CDC) to stop
using the "empirical" definition (also known as the Reeves 2005
definition) to define Chronic Fatigue Syndrome (CFS) patients in CFS
The CDC claim it is simply a way of operationalizing the Fukuda (1994)
definition. However the prevalence rates suggest otherwise: the
"empirical" definition gives a prevalence rate of 2.54% of the adult
population compared to 0.235% (95% confidence interval, 0.142%-0.327%)
and 0.422% (95% confidence interval, 0.29%-0.56%) when the Fukuda definition
was used in previous population studies in the US[4,5].
The definition lacks specificity. For example, one research study found
that 38% of those with a diagnosis of a Major Depressive Disorder were
misclassified as having CFS using the empirical/Reeves definition.
 Reeves WC, Wagner D, Nisenbaum R, Jones JF, Gurbaxani B, Solomon L,
Papanicolaou DA, Unger ER, Vernon SD, Heim C. Chronic fatigue syndrome--a
clinically empirical approach to its definition and study. BMC Med. 2005 Dec
15;3:19. Link: http://www.biomedcentral.com/1741-7015/3/19
 Fukuda K, Straus SE, Hickie I, Sharpe MC, Dobbins JG, Komaroff A. The
chronic fatigue syndrome; a comprehensive approach to its definition and
study. Ann Int Med 1994, 121:953-959.
 Reeves WC, Jones JF, Maloney E, Heim C, Hoaglin DC, Boneva RS, Morrissey
M, Devlin R. Prevalence of chronic fatigue syndrome in metropolitan, urban,
and rural Georgia. Popul Health Metr. 2007 Jun 8;5:5.
 Reyes M, Nisenbaum R, Hoaglin DC, Unger ER, Emmons C, Randall B, Stewart
JA, Abbey S, Jones JF, Gantz N, Minden S, Reeves WC: Prevalence and
incidence of chronic fatigue syndrome in Wichita, Kansas. Arch Int Med 2003,
 Jason LA, Richman JA, Rademaker AW, Jordan KM, Plioplys AV, Taylor RR,
McCready W, Huang CF, Plioplys S. A community-based study of chronic fatigue
syndrome. Arch Intern Med. 1999 Oct 11;159(18):2129-37.
 Jason, LA, Najar N, Porter N, Reh C. Evaluating the Centers for Disease
Control's empirical chronic fatigue syndrome case definition. Journal of
Disability Policy Studies 2008, doi:10.1177/1044207308325995.
Problems with the New CDC CFS Prevalence Estimates
Leonard Jason, Ph.D., DePaul University
I'm the first to admit that this isn't exactly the "catchiest" petition that
has ever been created. One might think it would be lucky to get a few dozen
However already, in just over a month, 651 people have signed (at the time
of writing). Many have left comments which can be read on the site:
[Aside: other people have also left comments but for some reasons the
comments have not gone up].
I believe this shows the depth of feeling there is on this issue.
If one looks at the CFSAC's function, it is clear that the issues relating
to the definition are fairly central:
The Committee shall advise and make recommendations to the Secretary,
through the Assistant Secretary for Health, on a broad range of topics
including: (1) the current state of knowledge and research about the
epidemiology and risk factors relating to chronic fatigue syndrome, and
identifying potential opportunities in these areas; (2) current and proposed
diagnosis and treatment methods for chronic fatigue syndrome; and (3)
development and implementation of programs to inform the public, health care
professionals, and the biomedical, academic and research communities about
chronic fatigue syndrome advances.
For example, as I pointed out, prevalence estimates from CDC research jumped
from 235 per 100,000 to 2540 per 100,000! That is to say that nearly 11
times as many people are diagnosed with the new "definition" as the old
definition. This is clearly relevant for point 1. Who are these people?
Do they all really have the same illness? I find it strange that, for
example, somebody can score 100 out of 100 on the physical functioning
subscale of the SF-36 (as well scoring the maximum on other subscales) but
if they score low on the Role Emotional Subscale, they can be classed as
being functionally impaired and hence satisfy that important part of the CFS
definition. I believe this allows too many people who may not have CFS to
satisfy the criteria. This concern has been demonstrated to be valid by the
study by Leonard Jason and colleagues (2008) which found that 38% of those
with Major Depressive Disorder were misclassified as having CFS using the
One of the external reviewers for the CDC program highlighted this problem
when he was a reviewer for the Georgia prevalence study paper published in
2007. Leonard Jason alluded to this in a piece he wrote that year:
'In Peter White's Dec. 3. 2006 review
(http://www.biomedcentral.com/imedia/1083914155124266_comment.pdf) of Reeves
et al.'s (2007) article, he states: The use of physical function, role
physical and social function sub-scales is consistent with the International
Study criteria for CFS, which states that the illness "results in
substantial reduction in previous levels of occupational, educational,
social, or personal activities." (Reeves et al, 2003). The use of role
emotional is not, since it specifically asks about change in function "as a
result of any emotional problems". And later White states that "In order to
make these important criteria consistent with other studies, I think the
authors need to re-analyse their data, omitting this sub-scale.'
Prof. White made other criticisms of the definition in his reviews - I'm
including as an appendix one of his reviews on the issue.
If one has a heterogeneous group of patients, it can mean that in
intervention trials, if "true" CFS patients only make up a tiny fraction of
the cohort, useful interventions could come up as showing no effect (or even
being detrimental); alternatively, interventions may come up as being useful
for CFS when in fact if one had only looked at those with "true" CFS, the
intervention may have made no difference or may even have been detrimental.
So you can see it is a serious issue.
Similarly with regard to risk factors for the illness, incorrect information
could be gathered. For example, the CDC have now done not one but two
studies looking at the relationship between CFS and Childhood trauma.
However the results may have looked very different had a different
definition been used. The same applies to biological testing and also the
search for biomarkers - having a very broad and inexact definition means
progress in that area may never occur.
I am unsure of the specifics of how the CFSAC acts but I hope it will be
able to do something on this issue. My views are inline with what I have
read by Dr Leonard Jason on the issue so I would ask people to listen
carefully to whatever points he has to make on the issue.
I am appending comments I have posted on articles, which show my general
concerns. These are generally referenced comments, which had to be reviewed
before they were posted (beside the CDC papers). The method the CDC is
using to define Chronic Fatigue Syndrome can be a bit difficult to
understand so the comments may also help people understand what the
definition actually is.
Thank you for your time.
Appendix 1: Comments I have been made on the "empirical definition" (Reeves,
2005) that have been "published" online beside CDC papers.
[Aside: I have not actually included all of the comments here]
[Internet version: In what I submitted, I included the comments (I didn't
send in the first comment from the first link). However if I included them
here, it would make the E-mail very long. It is also much easier to read
the comments at the site as they are formatted]
Prof. Peter White commenting on the empirical definition (Reeves, 2005)