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R. Pierce Butler
medicine forum addict
Joined: 23 Jun 2005
Posts: 86
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 Posted: Sat May 13, 2006 8:41 pm Post subject:
Stress tests - inaccurate
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I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all? |
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Susan
medicine forum Guru
Joined: 05 May 2005
Posts: 932
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| Posted: Sat May 13, 2006 8:53 pm Post subject:
Re: Stress tests - inaccurate
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x-no-archive: yes
R. Pierce Butler wrote:
| Quote: | I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all?
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To defray the cost of the doctor's machinery.
Seriously.
Susan |
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R. Pierce Butler
medicine forum addict
Joined: 23 Jun 2005
Posts: 86
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| Posted: Sat May 13, 2006 9:25 pm Post subject:
Re: Stress tests - inaccurate
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Susan <nevermind@nomail.com> wrote in news:4cmvahF172emtU1@individual.net:
| Quote: | x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them
performed when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A
907- 555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have
significant heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive
rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
|
Isn't that a bit unethical? I think there has to be a better answer. |
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Susan
medicine forum Guru
Joined: 05 May 2005
Posts: 932
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| Posted: Sat May 13, 2006 9:38 pm Post subject:
Re: Stress tests - inaccurate
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x-no-archive: yes
R. Pierce Butler wrote:
| Quote: |
Isn't that a bit unethical? I think there has to be a better answer.
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In the U.S., doctors get paid well for procedures, not for spending
their time with a patient or for researching and thinking about his case.
You may think it's unethical, but it's just economics at work.
Stress testing will pick up some gross abnormalities.
The % of accuracy goes even lower if you're female.
Susan |
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Jim Chinnis
medicine forum Guru
Joined: 30 Apr 2005
Posts: 1030
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| Posted: Sat May 13, 2006 10:13 pm Post subject:
Re: Stress tests - inaccurate
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Susan <nevermind@nomail.com> wrote in part:
| Quote: | x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
|
Actually, those miss and false positive rates look fairly good. They are
meaningless without specifying the reference population, though.
Using the medians of the ranges, if you have "significant" heart disease,
the probabability the simple stress test in a doctor's office will detect it
is 75%. (And the chance it will miss it is 25%.) If you have no
"significant" heart disease, the test will correctly class you as ok, with
probability 65%.
Stress tests don't just result in "abnormal" and "normal," though. They add
information to a clinical picture.
You could improve the probabilities of correct classification by having an
angiogram Exploratory surgery would give essentially zero error
probabilities.
--
Jim Chinnis Warrenton, Virginia, USA |
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Susan
medicine forum Guru
Joined: 05 May 2005
Posts: 932
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| Posted: Sat May 13, 2006 10:20 pm Post subject:
Re: Stress tests - inaccurate
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x-no-archive: yes
Jim Chinnis wrote:
| Quote: | Susan <nevermind@nomail.com> wrote in part:
x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
Actually, those miss and false positive rates look fairly good. They are
meaningless without specifying the reference population, though.
Using the medians of the ranges, if you have "significant" heart disease,
the probabability the simple stress test in a doctor's office will detect it
is 75%.
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Not if you're female. :-/
Susan |
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Kurt Gavin
medicine forum Guru
Joined: 07 Apr 2006
Posts: 439
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| Posted: Sat May 13, 2006 10:20 pm Post subject:
Re: Stress tests - inaccurate
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"R. Pierce Butler" <spamsucks@google.com> wrote in message
news:Xns97C2A71E92B5Amc2500183316chgoill@10.232.1.1...
| Quote: | Susan <nevermind@nomail.com> wrote in news:4cmvahF172emtU1@individual.net:
x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them
performed when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A
907- 555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have
significant heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive
rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
Isn't that a bit unethical? I think there has to be a better answer.
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No, she gave the right answer. Another thing, over the years I've heard
studies cited that claimed about 1/3 of heart surgeries were unneccesary and
were done for the money. |
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Jim Chinnis
medicine forum Guru
Joined: 30 Apr 2005
Posts: 1030
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| Posted: Sat May 13, 2006 10:34 pm Post subject:
Re: Stress tests - inaccurate
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Susan <nevermind@nomail.com> wrote in part:
| Quote: | x-no-archive: yes
Jim Chinnis wrote:
Susan <nevermind@nomail.com> wrote in part:
x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
Actually, those miss and false positive rates look fairly good. They are
meaningless without specifying the reference population, though.
Using the medians of the ranges, if you have "significant" heart disease,
the probabability the simple stress test in a doctor's office will detect it
is 75%.
Not if you're female. :-/
|
Well, yeah, according to the numbers supplied. Different reference groups
should have different error rates, though. But we only have one set here.
--
Jim Chinnis Warrenton, Virginia, USA |
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Andrew B. Chung, MD/PhD
medicine forum Guru
Joined: 25 Mar 2005
Posts: 8540
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| Posted: Sun May 14, 2006 5:40 am Post subject:
Re: Stress tests - inaccurate
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Jim Chinnis wrote:
| Quote: | Susan <nevermind@nomail.com> wrote in part:
x-no-archive: yes
R. Pierce Butler wrote:
I have been reading about stress tests and wonder why MDs want them performed
when they are grossly innacurate in determining problems.
http://www.ocalaregional.com/CustomPage.asp?guidCustomContentID=%7B1A49A907-
555E-4FF8-ACFE-15C3B5104AE8%7D says the following:
"20-30% of patients with "normal" stress tests will still have significant
heart disease (false negative rate).
20-50% of patients can have falsely abnormal studies (false positive rate)."
Why should anyone have a stress test at all?
To defray the cost of the doctor's machinery.
Seriously.
Susan
Actually, those miss and false positive rates look fairly good. They are
meaningless without specifying the reference population, though.
|
Correct.
| Quote: | Using the medians of the ranges, if you have "significant" heart disease,
the probabability the simple stress test in a doctor's office will detect it
is 75%. (And the chance it will miss it is 25%.) If you have no
"significant" heart disease, the test will correctly class you as ok, with
probability 65%.
Stress tests don't just result in "abnormal" and "normal," though. They add
information to a clinical picture.
|
Correct.
| Quote: | You could improve the probabilities of correct classification by having an
angiogram Exploratory surgery would give essentially zero error
probabilities.
|
Neither of these two latter testing modalities help the physician match
symptoms with pathology. Collateral circulation often does not show up
on an angiogram and is underappreciated during cardiovascular surgery
(no such thing as exploratory cardiovascular surgery except
unintentional when the cardiothoracic surgeon finds something
unanticipated that makes continuing the surgery as planned unwise).
Prayerfully in Christ's amazing love,
Andrew
http://tinyurl.com/mpuzr |
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