e-journal

Accrual by groups in trials with discrete-time survival endpoints

---

In many fields of science, event status is often recorded in intervals or
at discrete points in time and can be investigated in experimental settings. Conducting
such trials requires thorough planning before they are actually performed.
Purpose To investigate accrual by groups in a trial with discrete-time survival endpoints
and to describe how to choose the number of accrual groups, the size of the
accrual groups, and the duration of the trial to achieve a sufficient power level.
Methods In trials with multiple time periods, the event status is recorded at the
end of each period, but the event may occur at any time between the time points
the measurements are taken. Therefore, time is recorded discretely, but the underlying
process is continuous. To find the risk of event occurrence in each time interval,
a continuous-time survival function is used and the generalized linear model is
applied.
Results It is observed that the combination of the number of accrual groups, the
size of the accrual groups, and the duration of the trial that gives a sufficient power
level depends on the shape of the continuous-time survival function, the proportion
of subjects who have experienced the event after a fixed number of time periods,
and the size of the treatment effect.
Limitations The results of the study are only presented graphically, because there is
no simple closed-form expression for finding the variance of the treatment effect.
The authors provide MATLAB software to perform the power calculations.
Conclusions More subjects should be recruited in each accrual group or more
accrual groups should be included if the effect size or the proportion of the subjects
who have experienced the event after a fixed number of time periods decreases, or
the probability of the event occurrence is concentrated toward the end of the study
duration.

---

Ketersediaan

Tidak ada salinan data

Informasi Detail

Judul Seri

Clinical Trials

No. Panggil

-

Penerbit

: SAGE Publications Ltd., 2013

Deskripsi Fisik

Clinical Trials 2013; 10: 32–42

Bahasa

English

ISBN/ISSN

-

Klasifikasi

-

Tipe Isi

-

Tipe Media

-

Tipe Pembawa

-

Edisi

-

Subjek

KESEHATAN
FARMASI

Info Detail Spesifik

-

Pernyataan Tanggungjawab

hasnidar

Versi lain/terkait

Lampiran Berkas

Komentar

---

Anda harus masuk sebelum memberikan komentar