Hi everyone, i'm working on a dataset with counting process structure. I have something like this:
Notice that the event is hospital readmission, so i thought a PWP-TT was a good choice. I tested de PH assumption using this code:
The results suggest that substance has a time-dependent effect, so i tried this:
The question is if its possible to plot the baseline hazard for the strata, taking into account the TD effects?
i found solutions for td effects like
but i dont know how to plot strata and td effects jointly, it is possible? it makes sense?
Thank you for your help
| Id | Status | Event | tstart | tstop | sus |
| 1 | 1 | 1 | 0 | 16377 | cocaine |
| 1 | 0 | 2 | 18019 | 18213 | alcohol |
| 2 | 0 | 1 | 0 | 18169 | alcohol |
| 3 | 1 | 1 | 0 | 16037 | cocaine paste |
| 3 | 1 | 2 | 16049 | 16129 | cocaine paste |
| 3 | 0 | 3 | 16212 | 16275 | cocaine paste |
| 4 | 0 | 1 | 0 | 16617 | cocaine |
| 5 | 1 | 1 | 0 | 16750 | marijuana |
| 5 | 0 | 2 | 17123 | 17525 | marijuana |
Code:
stset tstop, fail(status) exit(time .) id(id) enter(tstart) stpm2 sus, df(5) scale(hazard) predict su1, at(sus 1) hazard predict su2, at(sus 2) hazard predict su3, at(sus 3) hazard predict su4, at(sus 4) hazard predict su5, at(sus 5) hazard stphplot, by(sus) stcox i.sus stphtest, rank detail
Code:
stphtest, rank detail
Test of proportional-hazards assumption
Time: Rank(t)
----------------------------------------------------------------
| rho chi2 df Prob>chi2
------------+---------------------------------------------------
1b.sus | . . 1 .
2.sus | -0.05253 66.45 1 0.0000
3.sus | -0.08080 156.46 1 0.0000
4.sus | -0.04212 42.66 1 0.0000
5.sus | -0.10743 276.38 1 0.0000
------------+---------------------------------------------------
global test | 341.50 4 0.0000
----------------------------------------------------------------
Code:
stcox sus, tvc(sus) strata(event)
Code:
Stratified Cox regr. -- Breslow method for ties
No. of subjects = 79,710 Number of obs = 103,775
No. of failures = 24,066
Time at risk = 1338295692
LR chi2(2) = 2273.74
Log likelihood = -239219.92 Prob > chi2 = 0.0000
------------------------------------------------------------------------------
_t | Haz. Ratio Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
main |
sus | 3.071586 .211246 16.32 0.000 2.684244 3.514823
-------------+----------------------------------------------------------------
tvc |
sus | .9999414 4.21e-06 -13.90 0.000 .9999332 .9999497
------------------------------------------------------------------------------
Stratified by event
Note: Variables in tvc equation interacted with _t.
i found solutions for td effects like
Code:
scurve_tvc
Thank you for your help
