Changing x-axis from days into years on kaplan meier

[Roshani Patel]

Dear Stata community,

Thank you for all your help so far.

I am doing some KM analysis for my study and the time in is days. The last exit on the survival data is about 13,000 days. In order for the reader to understand clear, I would like to convert the x-axis into years (ideally 5 yearly intervals e.g. 5, 10, 15, 20, 25, 30, 35). I am reluctant to convert the actual variable into years as this results in multiple records at same instant and therefore I lose some of the data. Is there a way just to change the the x-axis on the KM graph into years?

Many thanks for your help once again,

Roshani

[Andrew Musau]

For twoway type graphs, you have the option of specifying your own x/y labels. So do the math and add the labels

sysuse census
tw scatter marriage pop, xlab(5000000 "13" 10000000 "Whatever") scheme(s1color)

Res.:

[Nick Cox]

Andrew Musau has it right. Here is a helper command to do such conversion of scales. You want say 0(5)40 in years but your scale is days.

ssc install mylabels
mylabels 0(5)40, myscale(365.25*@) local(xlabel)

displays this (which is also held in the local macro.

0 "0" 1826.25 "5" 3652.5 "10" 5478.75 "15" 7305 "20" 9131.25 "25" 10957.5 "30" 12783.75 "35" 14610 "40"

so that you can use the local macro in your graph call or even copy and paste into that.

[Marcos Almeida]

Just speculating, maybe the stset option - scale(365.25) - would do the trick.

[Nick Cox]

Marcos Almeida is I guess right.

I've never used Kaplan-Meier myself.

[Roshani Patel]

Dear All,

Thank you for your fast responses!

Marcos - I used your scale option and this has worked perfectly!!

Thanks so much!!!
Roshani

[Marcos Almeida]

Thanks for informing the suggestion worked well.