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name: <unnamed>
log: Z:\laplace\laplace_ex1.smcl
log type: smcl
opened on: 30 Oct 2017, 10:13:45
. /*
> The most recent version of the -laplace- command dates from 9 June 2013
> To install it use the following command
> net install laplacereg, from(http://www.imm.ki.se/biostatistics/stata) replace
> */
.
. use "http://www.imm.ki.se/biostatistics/data/kidney.dta", clear
(Metastatic renal carcinoma trial. MRCRCC. Lancet. 1999, 353:14-7)
. stset months , fail(cens)
failure event: cens != 0 & cens < .
obs. time interval: (0, months]
exit on or before: failure
------------------------------------------------------------------------------
347 total observations
0 exclusions
------------------------------------------------------------------------------
347 observations remaining, representing
322 failures in single-record/single-failure data
4511.211 total analysis time at risk and under observation
at risk from t = 0
earliest observed entry t = 0
last observed exit t = 74.56438
. sts graph , by(trt)
failure _d: cens
analysis time _t: months
. // Median survival
. stci , by(trt)
failure _d: cens
analysis time _t: months
| no. of
trt | subjects 50% Std. Err. [95% Conf. Interval]
-------------+-------------------------------------------------------------
MPA | 175 6.80548 .8902896 4.86575 8.15342
IFN | 172 9.830137 .8982793 7.7589 11.7041
-------------+-------------------------------------------------------------
total | 347 7.956164 .5699226 6.90411 9.1726
. laplacereg months trt, q(50) fail(cens)
Laplace regression No. of subjects = 347
No. of failures = 322
------------------------------------------------------------------------------
| Robust
months | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
q50 |
trt | 3.106033 1.219963 2.55 0.011 .714949 5.497118
_cons | 6.805478 .718854 9.47 0.000 5.39655 8.214406
------------------------------------------------------------------------------
. // Median survival in new drug group (trt = 1)
. lincom _cons + trt
( 1) [q50]trt + [q50]_cons = 0
------------------------------------------------------------------------------
months | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
(1) | 9.911511 .9856773 10.06 0.000 7.979619 11.8434
------------------------------------------------------------------------------
. // 25th, 50th, and 75th Percentile
. laplacereg months trt, q(25 50 75) fail(cens)
Laplace regression No. of subjects = 347
No. of failures = 322
------------------------------------------------------------------------------
| Robust
months | Coef. Std. Err. z P>|z| [95% Conf. Interval]
-------------+----------------------------------------------------------------
q25 |
trt | 1.476854 .714114 2.07 0.039 .0772168 2.876492
_cons | 2.498634 .373248 6.69 0.000 1.767082 3.230187
-------------+----------------------------------------------------------------
q50 |
trt | 3.106033 1.219963 2.55 0.011 .714949 5.497118
_cons | 6.805478 .718854 9.47 0.000 5.39655 8.214406
-------------+----------------------------------------------------------------
q75 |
trt | 3.811313 4.016758 0.95 0.343 -4.061387 11.68401
_cons | 15.87946 1.604595 9.90 0.000 12.73451 19.02441
------------------------------------------------------------------------------
. log close
name: <unnamed>
log: Z:\laplace\laplace_ex1.smcl
log type: smcl
closed on: 30 Oct 2017, 10:13:47
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