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st:ODDSRISK module and continous covariates


From   Nanlesta Pilgrim <[email protected]>
To   [email protected]
Subject   st:ODDSRISK module and continous covariates
Date   Fri, 4 Feb 2011 00:44:51 -0500

 I'm  new to the ODDSRISK module.  My dataset is longitudinal and I'm
using log binomial regression (specifically GEE) to model my outcome
which is not rare.  The problem is that the adjusted model does not
converge.  As such, we decided to do logistic regression and then
convert the ORs to RRs using Zhang's formula.  In reading Zhang's
paper and the description of ODDSRISK, all the examples are based on
the predictors being binary or categorical.  When I compare the ORs
from the logistic regression to that of the ODDSRISK they change
somewhate in the reprint (see below).  As such, I'm wondering if
anyone can point me to sources on how to appropriately transform ORs
to RRs for continous predictors in multivariate models?

. xi:xtgee marrphys  disalcdays i.rdisoccup disageyrs i.rdiseducyrs
i.disipvatt manypartner  ///
> i.rcrossgenrltn i.newsaidsrsk  i.rdiswealth newdispoly disfamsize i.marrstructure i.newmarrparstatus, nolog f(bin) l(logit)
> corr(uns) vce(robust) eform
i.rdisoccup       _Irdisoccup_0-15    (naturally coded; _Irdisoccup_0 omitted)
i.rdiseducyrs     _Irdiseducy_0-1     (naturally coded; _Irdiseducy_0 omitted)
i.disipvatt       _Idisipvatt_0-3     (naturally coded; _Idisipvatt_0 omitted)
i.rcrossgenrltn   _Ircrossgen_0-1     (naturally coded; _Ircrossgen_0 omitted)
i.newsaidsrsk     _Inewsaidsr_0-7     (naturally coded; _Inewsaidsr_0 omitted)
i.rdiswealth      _Irdiswealt_0-2     (naturally coded; _Irdiswealt_0 omitted)
i.marrstructure   _Imarrstruc_0-1     (naturally coded; _Imarrstruc_0 omitted)
i.newmarrpars~s   _Inewmarrpa_0-3     (naturally coded; _Inewmarrpa_0 omitted)

GEE population-averaged model                   Number of obs      =      1109
Group and time vars:              id time1      Number of groups   =       983
Link:                                logit      Obs per group: min =         1
Family:                           binomial                     avg =       1.1
Correlation:                  unstructured                     max =         2
                                                Wald chi2(23)      =     46.59
Scale parameter:                         1      Prob > chi2        =    0.0025

                                     (Std. Err. adjusted for clustering on id)
------------------------------------------------------------------------------
             |             Semirobust
marrphys | Odds Ratio   Std. Err.      z    P>|z|     [95% Conf. Interval]
-------------+----------------------------------------------------------------
  disalcdays |   1.633986   .3207118     2.50   0.012     1.112188    2.400593
_Irdisoccu~1 |   1.112781   1.476963     0.08   0.936     .0825341    15.00327
_Irdisoccu~3 |   1.282093   1.700855     0.19   0.851     .0952129    17.26408
_Irdisocc~15 |   1.652254    2.21541     0.37   0.708     .1193305    22.87718
   disageyrs |   .9908942   .0936334    -0.10   0.923      .823368    1.192506
_Irdiseduc~1 |   1.329675   .3183714     1.19   0.234     .8316442    2.125952
_Idisipvat~1 |   3.318917   1.477306     2.70   0.007     1.387114    7.941099
_Idisipvat~2 |   3.637085   1.603931     2.93   0.003     1.532425    8.632326
_Idisipvat~3 |   3.059167   1.465666     2.33   0.020     1.196154    7.823824
 manypartner |   1.419517   .4760212     1.04   0.296     .7356958    2.738941
_Ircrossge~1 |    .887271   .1854241    -0.57   0.567     .5890743    1.336419
_Inewsaids~1 |   1.798441   .7136119     1.48   0.139     .8263116    3.914249
_Inewsaids~2 |   2.751564   1.126913     2.47   0.013     1.233011    6.140338
_Inewsaids~3 |   2.001107   .9327574     1.49   0.137     .8026158    4.989224
_Inewsaids~7 |   .7764457   .5858674    -0.34   0.737     .1769443    3.407105
_Irdisweal~1 |   1.504489    .368856     1.67   0.096     .9304643    2.432643
_Irdisweal~2 |   1.417855   .3204714     1.54   0.122     .9104129    2.208132
  newdispoly |   2.026248    .728694     1.96   0.050      1.00133    4.100227
  disfamsize |   .9496166   .0639217    -0.77   0.442     .8322451    1.083541
_Imarrstru~1 |   2.023349   .7418727     1.92   0.055     .9862177    4.151154
_Inewmarrp~1 |   1.144711   .3113246     0.50   0.619     .6717321    1.950721
_Inewmarrp~2 |   2.019597   .6692795     2.12   0.034     1.054831    3.866754
_Inewmarrp~3 |   1.196413   .3741348     0.57   0.566     .6481846    2.208328
------------------------------------------------------------------------------

.
.
. xi:oddsrisk marrphys disalcdays i.rdisoccup  disageyrs i.rdiseducyrs
  i.disipvatt manypartner  ///
> i.rcrossgenrltn i.newsaidsrsk  i.rdiswealth newdispoly disfamsize i.marrstructure i.newmarrparstatus
i.rdisoccup       _Irdisoccup_0-15    (naturally coded; _Irdisoccup_0 omitted)
i.rdiseducyrs     _Irdiseducy_0-1     (naturally coded; _Irdiseducy_0 omitted)
i.disipvatt       _Idisipvatt_0-3     (naturally coded; _Idisipvatt_0 omitted)
i.rcrossgenrltn   _Ircrossgen_0-1     (naturally coded; _Ircrossgen_0 omitted)
i.newsaidsrsk     _Inewsaidsr_0-7     (naturally coded; _Inewsaidsr_0 omitted)
i.rdiswealth      _Irdiswealt_0-2     (naturally coded; _Irdiswealt_0 omitted)
i.marrstructure   _Imarrstruc_0-1     (naturally coded; _Imarrstruc_0 omitted)
i.newmarrpars~s   _Inewmarrpa_0-3     (naturally coded; _Inewmarrpa_0 omitted)

---------------------------------------------------------------------
Incidence for unexposed risk group =     0.1373
---------------------------------------------------------------------
Predictor    Odds Ratio   Risk Ratio     [95% Conf. Interval]
---------------------------------------------------------------------
disalcdays      1.6031       1.4805       1.0533       2.0248
_Irdisoccup_1   1.1745       1.1470       0.1436       4.6239
_Irdisoccup_3   1.3855       1.3158       0.1650       4.9334
_Irdisoccup_15   1.8436      1.6523       0.2130       5.3963
disageyrs       1.0244       1.0210       0.8633       1.2021
_Irdiseducy_1   1.2594       1.2161       0.8245       1.7434
_Idisipvatt_1   3.8656       2.7744       1.4022       4.4693
_Idisipvatt_2   3.9932       2.8304       1.4420       4.5213
_Idisipvatt_3   3.1882       2.4518       1.1189       4.2725
manypartner     1.6944       1.5470       0.9356       2.4063
_Ircrossgen_1   0.8891       0.9029       0.6262       1.2783
_Inewsaidsr_1   1.9766       1.7430       0.8445       3.1325
_Inewsaidsr_2   3.1465       2.4305       1.2359       4.0136
_Inewsaidsr_3   2.1753       1.8731       0.8036       3.5800
_Inewsaidsr_7   0.8583       0.8753       0.2206       2.7236
_Irdiswealt_1   1.4401       1.3581       0.9031       1.9714
_Irdiswealt_2   1.4018       1.3286       0.9154       1.8733
newdispoly      2.1276       1.8424       1.0139       3.0218
disfamsize      0.9578       0.9634       0.8597       1.0774
_Imarrstruc_1   1.7927       1.6168       0.8463       2.7852
_Inewmarrpa_1   1.2046       1.1717       0.7470       1.7724
_Inewmarrpa_2   2.1030       1.8265       1.0965       2.8210
_Inewmarrpa_3   1.2156       1.1807       0.7026       1.8907
---------------------------------------------------------------------

.

Thanks!
Nanlesta

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