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  • Accounting for baseline in a multiple outcomes radiology analysis. Help!

    Dear all,
    I have a study with different outcomes represented by differences in brain areas measured at two different timepoints. The length of followup varies from subject to subject and is indicated by the variable "Months_between_MRI Diagnosis".

    The areas are indicated starting from the first, "a2", while the others go progressively up to 67 (a3, a4...a67).

    So the outcomes of my analysis are "deltaa2", "deltaa3"..."deltaa67".

    The goal of the analysis is to understand whether the delta of each area depends on the followup time or not.

    I am using the "wyoung" command to perform a p correction for multiple testing.

    If I didn't consider the baseline, the command would be:

    Code:
    wyoung deltaa2-deltaa67, cmd(regress OUTCOMEVAR Gender Months_between_MRI Diagnosis) familyp(Months_between_MRI) bootstraps(1000) seed(20) replace
    However, if I wanted to include the baseline, for each area, how could I do it?
    It's a problem, because the wyoung command corrects all the regression models for the same covariates, while the baseline of the different areas are obviously different from each other.

    Does anyone have an idea? I really don't know how to get out of this problem.

    For convenience, below I report the dataset for the first 5 areas

    Code:
    * Example generated by -dataex-. For more info, type help dataex
    clear
    input byte(id Age Gender) float(deltaa2 deltaa3 deltaa4 deltaa5 baselinea2 baselinea3 baselinea4 baselinea5)
     1 30 0   .0019999924  -.02300009 -.036999952  -.23999995 2.406 2.544 1.987 2.917
     2 36 0          .739   .05800011    .3919999   .26099998 1.969 2.105 1.668 1.083
     3 34 0    -.12099997       -.182        .661        .038 2.637 2.274 1.796  .944
     4 44 0    -.13100006  -.14399996    .9399999        .603 1.936 2.137 1.374   .83
     5 49 0          .207       -.337    .7459999 -.003000028 1.783 2.322 1.403  .945
     6 25 0     -.3330001       -.789        .313      -1.806 3.064 2.445 1.973 3.265
     7 24 0     .12799993       -.327       1.289        .495 2.386 2.184  1.28  .905
     8 15 1     -.7780001   -.1940001    .2489999       -.928 3.226 2.501 2.098 3.217
     9 32 0         -.329   .51400006    .7830001        .808 2.497 1.735 1.562  .935
    10 13 0         -.284  -.57399994    .3190001        .608  2.35 2.353 1.821 1.099
    11 49 0      .9899999   .58000004        .916        1.46 1.646 1.771 1.396   .79
    12 67 1     .14900011   .17399994        .541  -.22399995 3.412 2.567 2.179 3.151
    13 47 0    -.26400006   .17299993  -.20400003        .587 2.712 2.453  2.15 2.979
    14 30 1     -.7479999       -.673        .488      -2.184 3.253  2.56  2.13 3.245
    15 22 0     -.7120001  -.03599991       -.406      -1.771 2.609 2.617 2.101 3.211
    16 55 0     -.5170001       -.405         .23      -1.223 2.969  2.57 2.125 2.792
    17 28 0     -.2819999  -.23100004    .6030001        .828 2.468 2.373 1.797 1.965
    18 44 0          .622    .2019999        .525       2.658 1.987 2.293 1.431 1.117
    19 35 0    -.04399993   .02899999   1.0109999        .753 2.145 2.333 1.375 1.023
    20 20 1     -.3540001  -.13600005   .04399997       -.352 3.204 2.571 2.167 3.707
    21 18 0      .5030001   -.4240001    .4259999        .991 1.864  2.84 1.822 1.295
    22 54 0      .9620001   .17199998       1.673       1.788 2.043 2.006  1.06  .785
    23 39 0    -.20200007   .03000001   .59200007    .3920001 2.272 1.983 1.575 2.005
    24 21 0     -.7720001       -.414        .398       -1.82 2.865 2.237 2.006 3.356
    25 24 0      .7089999   -.6439999       1.101    .5389999 2.039 2.561 1.637 1.574
    26 38 1     .04400001    .4290001    .7620001        .379 2.492 1.823  1.73 1.453
    27 33 0      .3289999   -.4630001    .8069999   .22400004 2.113 2.546 1.392 1.468
    28 75 1         1.193    .5079999   .11899997        .309  1.88 1.753 1.633 1.648
    29 38 1     -.6810001  -.57400006   .04899991  -1.1570001  2.84 2.458 2.097 3.077
    30 19 1         -.664   -.4990001   .11499997      -1.177 2.615 2.619 2.267   3.2
    31 44 0     -.8909999   -.3210001   .16800007        -.67 3.337 2.539 2.285 2.756
    32 45 0          .213    .3359999        .772         .74 2.284 1.599  1.35  .837
    33 34 0          .614         .51       1.039       1.702 2.965 2.174   .97  .945
    34 12 1      .4209999  -.26199993   .02200002 -.019000005 2.077 2.373 1.856 1.575
    35 53 0     1.1710001    .7800001       1.607       1.911 1.851 1.804 1.223 1.132
    36 45 1             0           0           0           0     0     0     0     0
    37 20 0        -1.591       -1.62      -1.253       -1.57 1.591  1.62 1.253  1.57
    38 50 0     -.5209999  -.11800011   .27200004        .252 2.809 2.409 1.905 1.896
    39 47 1         -.883       -.488    .8060001       -1.64 3.199  2.39 2.127 3.321
    40 40 0          .424        .443       1.588        .862 2.343 1.909 1.219 1.089
    41 40 1      .4859999    .6459999    .5619999    .6940001 2.479 1.967 1.689  1.69
    42 63 1    .008999996   -.4620001        .357       -.934 2.945  2.69 2.268 3.273
    43 34 0             0           0           0           0     0     0     0     0
    44 24 0        -2.191      -2.684      -1.053      -1.124 2.191 2.684 1.053 1.124
    45 63 0     -.6969999   -.5000001 -.019000055      -1.937 2.755 2.712 2.102 3.464
    46 40 1         -.781       -.394    .0510001      -1.963 3.278 2.581 1.964 3.181
    47 33 0             0           0           0           0     0     0     0     0
    48 44 0    -.13000004 -.005999957       1.058  -.04499999 2.101 1.836 1.228 1.035
    49 27 1             0           0           0           0     0     0     0     0
    50 19 0          .398   -.2399999        .647    .9030001 2.059  2.38 1.573 1.409
    51 52 1    .019999957   .13000005        .645        .066 2.451 2.162 1.693 1.008
    52 30 0          .488   -.1919999        .915        .474 1.946 2.204 1.441  .945
    53 14 0    -1.1639999       -.708       -.246      -2.251   3.4 2.573 2.047 3.414
    54 66 0    .063000105       -.214       1.225    .6380001  2.35 2.053 1.158 1.177
    55 63 0    -.56600004   .11599991  -.11699998  -.14500012 2.711 2.201 2.041 3.242
    56 36 1        -1.102        .003   .28900003      -1.459  3.28 2.372 2.023 3.276
    57 18 1     -.6940001       -.381  -.10599995      -1.207 3.001 2.347 2.074  3.15
    58 37 1     -.7559999   -.7770001  -.09600002      -2.003 3.166 2.406 1.917 3.173
    59 50 0         1.307   .24700004    .8360001   .54899997 1.543 2.144 1.502 1.149
    60 33 0     -.6990001   -.6819999    .1060001      -1.595 2.772 2.576 2.113 3.672
    61 49 0         -.452  -.12399995        .315   -.8080001 3.179  2.62 2.113 2.987
    62 48 1    -.09499995  -.22099994    .1659999    .2479999 2.739 2.592  1.98 3.332
    63 20 1         -.798       -.434   .08999995   -.8780001 2.966 2.339 2.108 3.234
    64 72 1     .07299996   .53900003        .226       1.267 2.115  2.03 1.958 1.716
    66 45 1     -.4070001  -.44300005  -.12899995      -1.443 3.188 2.595 2.125 3.444
    67 53 1    -1.1020001   -.1880001        .867      -1.405 2.764 2.459 2.037 3.434
    68 24 0    -.22599994   .14999995 -.021000044   .36200005 2.837 2.354 2.117 3.075
    69 61 1    -.28399992  -.08000001   -.1970001   .15700006 3.125 2.465 2.501 2.852
    70 43 0     -.3899999       -.697  -.21200003      -1.397 2.793 2.358 2.145 3.063
    71 50 0     -.4679999   -.2589999    .3410001  -1.1519998 3.348 2.442 2.151 3.157
    72 25 0      .4440001   .17399994         1.4        .356 2.147 1.886 1.399 1.252
    73 16 0         1.297    .7469999        .296       1.918  1.42 1.846 1.569  1.71
    74 29 0 1.4305114e-08       -.473    .9079999    .7419999 1.985 2.349 1.603 1.165
    75 42 1     -.3659999   -.2980001  -.16099995   -.4830001 3.332 2.589 2.259 3.425
    76 50 0     .03100011    .1570001        .842  -.10600004 2.132 1.996 1.536 1.378
    77 41 0         -.396       -.659  -.26399997      -1.815 2.639 2.418 2.071 3.061
    78 24 0     .28700003         -.6       1.004   .17199996  2.42 2.572 1.813 1.039
    79 49 1     .10500007  -.11799993   1.1110001        .317 2.144 2.275 1.319   1.4
    80 39 0      .1520001       -.434   1.0070001   .33699995 2.317 2.228 1.271  .889
    81 17 1     .53999996   .05200009        .829    .7009999  2.28 1.983 1.408 1.547
    82 23 1   -.003000055   .15999997    .8239999    .3749999 2.586 1.796 1.299 1.198
    83 57 1     -.8339999       -.665   .02900001       -.961  3.07  2.55 2.234 3.205
    84 21 1         1.475   -.1119999        .402   .53900003 1.591 2.377 1.562  .936
    85 46 0          .719    .3800001        .465   .56799996 2.047 2.293 1.735 1.281
    end
    Last edited by Gianfranco Di Gennaro; 03 Oct 2024, 09:07.

  • #2
    You can allow controls to vary across outcomes by using the `controls()` option, or by using Syntax 2 to specify each individual regression. See Example 7 in the Stata help file.

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    Associate Professor of Finance and Economics
    University of Illinois
    www.julianreif.com

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