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From |
ajdc@unimelb.edu.au |

To |
statalist@hsphsun2.harvard.edu |

Date |
Tue, 24 Aug 2004 11:21:06 +1000 |

Dear Stata-listers, I apologise for this long post but would appreciate anyone's thoughts. I am attempting survival analysis of asynchronously interval-censored data. Some of my covariates start out equal to zero (before the subjects acquire particular attributes) but at later, different, times take on a value which then remains constant. I've used -stsplit- to set this up. I would like to analyse this time-varying characteristic in the model if possible. I can find techniques that handle interval censored data, or time-varying covariates, but not both. The asynchronous interval censoring seems to be the sticking point. I have tried using -stpm- but can't make it work with the stsplit data if I also try to specify interval-censoring. Here is an example of a 'fail' & 'non-fail' record: . st -> stset dayssurv, id(record) failure(fail) id: record failure event: fail != 0 & fail < . obs. time interval: (dayssurv[_n-1], dayssurv] exit on or before: failure . list record _t0 _t _d dayssurv fail left invwwt gr2t if record ==1 | record ==801, noobs +------------------------------------------------------------------+ | record _t0 _t _d dayssurv fail left invwwt gr2t | |------------------------------------------------------------------| | 1 0 60 0 60 . 60 .048 0 | | 1 60 100 0 100 . 100 .048 0 | | 1 100 150 0 150 . 150 .048 0 | | 1 150 180 0 180 . 180 .048 .051 | | 1 180 210 0 210 . 210 .048 .051 | | 1 210 288 0 288 0 288 .048 .051 | |------------------------------------------------------------------| | 801 0 60 0 60 . 60 .364 0 | | 801 60 100 0 100 . 100 .364 0 | | 801 100 143 1 143 1 100 .364 0 | +------------------------------------------------------------------+ * 'invwwt' isn't time-varying; gr2t is; 'left' == _t if no failure within the interval; left == _t0 if failure occurs within the interval . xi: stpm invwwt gr1 gr2t gr3t i.sex, left(left) scale(hazard) df(2) i.sex _Isex_0-100 (naturally coded; _Isex_1 omitted) cannot have both interval censoring and late entry r(198); Is anyone aware of techniques I can use in Stata to model this kind of situation, please? Thanks in advance for any thoughts, Angus --------------------------------- Dr Angus Campbell The Mackinnon Project Faculty of Veterinary Science, University of Melbourne 250 Princes Highway Werribee, Victoria, Australia * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

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