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RE: st: How to handle large (or small) odds ratios


From   Tim Evans <Tim.Evans@wmciu.nhs.uk>
To   "'statalist@hsphsun2.harvard.edu'" <statalist@hsphsun2.harvard.edu>
Subject   RE: st: How to handle large (or small) odds ratios
Date   Fri, 18 May 2012 12:53:17 +0100

Hi David,

Thanks for your response - my table formatting was not quite like that when it was sent!

Having reviewed the data behind the analysis, Ive decided the prudent approach is to remove the staging analysis for those particular adjusted O/Rs as they were based on small numbers. I've also had a look at: 

'How should one interpret 1.00E+00 as the LCI and UCI for Complex mixed
and stromal?  Is the standard error of that OR so small that the LCI
and UCI both round to 1.00?  Many other CIs are fairly wide.'

Again, having looked at the number of cases, they are based upon either a single case, or a very small fraction of the total and appear to be behaving in the exact manner as the reference group. Given the apparent lack of robustness here, I've removed these also.

Thanks for helping me to see the obvious. The results I have now are much more sensible.

Best wishes

Tim


-----Original Message-----
From: owner-statalist@hsphsun2.harvard.edu [mailto:owner-statalist@hsphsun2.harvard.edu] On Behalf Of David Hoaglin
Sent: 18 May 2012 12:09
To: statalist@hsphsun2.harvard.edu
Subject: Re: st: How to handle large (or small) odds ratios

Hi, Tim.

When your message arrived, the columns in the table didn't line up
well, and some entries for LCI and UCI were missing (e.g., Stage 2,
Stage 4, and Unknown stage --- I assume that Stage 1 is the reference
category).

The OR for Stage 3 seems to be 1.00E+00.  Does that have an
explanation when the ORs for Stage 2 and Stage 4 are 4.75E+05 and
1.66E+06, respectively?  All the ORs are adjusted ORs; but if the OR
for Stage 3 is actually 1.00E+00, it needs investigation.  In the
particular area of oncology, does other research indicate that having
a stage other than Stage 1 at diagnosis increases the risk of dying so
greatly?

Only the ORs for the Stages are very LARGE.  In the body of the table,
you could note that they are large, and give the details in a
footnote.  Do articles in the target journal have any examples of how
the journal prefers to handle large ORs?  Putting them in a footnote
should not be a problem when you submit your manuscript; the editor
can tell you what the journal prefers.

How should one interpret 1.00E+00 as the LCI and UCI for Complex mixed
and stromal?  Is the standard error of that OR so small that the LCI
and UCI both round to 1.00?  Many other CIs are fairly wide.

David Hoaglin

On Fri, May 18, 2012 at 5:06 AM, Tim Evans <Tim.Evans@wmciu.nhs.uk> wrote:
> Hi all,
>
> Not specifically a Stata question, however, I have run a series of logistic regressions (in Stata) comparing the effects of delay in treatment  and a persons likelihood of dying within a given time period. I have exported the analysis in readiness to produce tables, but what I wanted to know is whether there is a convention for dealing with very large odds ratios when producing publication tables, in order to produce neat legible tables. Many of these large odds ratios are very significant. Any advice gratefully received.
>
> Best wishes
>
> Tim
>
> Here is an example of my table:
>
>
> Characteristic                          OR      LCI     UCI
> Delay category
> Not Delayed                             *       1.00
> Delayed                                 1.12    0.47    2.67
> Morphological Type
> Adenomas and Adenocarcinomas            1.00
> Squamous Cell                           1.00    1.00    1.00
> Cystic, Mucinous and Serous             5.01    0.87    29.05
> Complex mixed and stromal               1.00    1.00E+00        1.00E+00
> Other                                           1.69    0.57    5.06
> Stage at diagnosis
> Stage 1                                 1.00
> Stage 2                                 4.75E+05        0.00E+00
> Stage 3                                 1.00E+00        1.00E+00        1.00E+00
> Stage 4                                 1.66E+06        0.00E+00
> Unknown stage                           3.65E+05        0.00E+00
> Age at diagnosis (per year)             *1.08   1.03    1.13
> Deprivation quintile
> Most deprived                           1.00
> More deprived                           1.08    0.29    4.01
> Average deprivation                     1.32    0.41    4.24
> Less deprived                           1.18    0.35    3.94
> Least deprived                          1.41    0.39    5.05
> Sex
> Male                                            *1.00
> Female                                  0.37    0.15    0.92
> Admission method
> Elective                                        1.00
> Emergency                                       1.31    0.45    3.78
> Charlson combordity
> 0                                               **1.00
> 1                                               0.79    0.27    2.31
> 2                                               0.86    0.17    4.26
> 3                                               13.77   4.87    38.92
> Diagnosis year
> 2006                                            1.00
> 2007                                            1.03    0.26    4.07
> 2008                                            1.24    0.33    4.59
> 2009                                            1.17    0.31    4.39
> 2010                                            1.04    0.30    3.65

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