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  • interpretation of transition probability graph

    Hi I produce the following transition probability graph using the following code

    Question:
    With reference to the graph produced below and the data in the dataset

    Am I correct to say at
    time 5.26 years these are the following transition probabilities for the state:
    Transition 1: Alive to Relapse = 0.28
    Transiiton 2: Alive to Dead = 0.11
    Transition 3: Relapse to died = 0.60


    The reason I ask is because when I draw an imaginary line at 5.26 years for the blue shaded area (it comes up to 0.4 region) on the graph

    Code:
    use http://fmwww.bc.edu/repec/bocode/m/multistate_example,clear
    
    
    ///rfi = relapse indication
    //osi overall survvior alive or fead, times rf - relapse free, os - overall srufvial 
    msset, id(pid) states(rfi osi) times(rf os) covariates(age)
    
    //Stores matrix callted tmat name, stores the values from transmatrix 
    mat tmat = r(transmatrix)
    
    //Displays tmat ie the values of transmatrix 
    mat list tmat
    
    //Declare survival data
    stset _stop, enter(_start) failure(_status=1) scale(12)
    
    //Only focus on those who had hormonal treatment
    drop if hormon ==0  
    
    
    stmerlin age if _trans1==1, distribution(weibull)
    estimate store m1
    
    
    stmerlin age if _trans2==1, distribution(weibull)
    estimate store m2
    
    stmerlin age if _trans3==1, distribution(weibull)
    estimate store m3
    
    ///transition probabilities for a patient with age 50  
    
    predictms, transmatrix(tmat) models(m1 m2 m3) probability at1(age 50)
    graphms
    Click image for larger version

Name:	Screenshot 2024-04-25 at 13.11.37.png
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Size:	1.42 MB
ID:	1751244

  • #2
    Rose:
    for each time period, transition probabilities should sum up to 1.
    Therefore, your statement sounds correct.
    What strikes me, though, is the fact that no patients seems to fall/remain in the health state: Alive No Relapse.
    Kind regards,
    Carlo
    (StataNow 18.5)

    Comment


    • #3
      Good point, I didn't think of that,
      However, I suppose if patient stayed alive - then they wouldn't have a transition probability



      As M Crowther shows his Markov model in slide 7

      https://web-archive.lshtm.ac.uk/csm....31-03-2017.pdf

      Comment

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