initiation of dialysis (Cooper et al. [22)). Patients were ran- domized to either i. an early start group, where dialysis was initiated when their estimated glomerular filtration rate (GFR) was be- tween 10.0 and 15.0 mL per minute per 1.73 m? of body surface area or ii. a late start group, where dialysis was initiated when their GFR was 5.0 to 7.0 mL per minute per 1.73 m? of body surface area. The primary outcome was total mortality. There were 404 patients assigned to the early start group, of whom 152 died. There were 424 patients assigned to the late start group, of whom 155 died over the same time period. Patients were enrolled from July 2000 to November 2008 and were followed for 3 years. 10.86 What test can be used to compare the mortality rates in the two groups? 10.87 Implement the test in Problem 10.86, and report a two-sided p-value.
initiation of dialysis (Cooper et al. [22)). Patients were ran- domized to either i. an early start group, where dialysis was initiated when their estimated glomerular filtration rate (GFR) was be- tween 10.0 and 15.0 mL per minute per 1.73 m? of body surface area or ii. a late start group, where dialysis was initiated when their GFR was 5.0 to 7.0 mL per minute per 1.73 m? of body surface area. The primary outcome was total mortality. There were 404 patients assigned to the early start group, of whom 152 died. There were 424 patients assigned to the late start group, of whom 155 died over the same time period. Patients were enrolled from July 2000 to November 2008 and were followed for 3 years. 10.86 What test can be used to compare the mortality rates in the two groups? 10.87 Implement the test in Problem 10.86, and report a two-sided p-value.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
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please solve 10.87 (use two different methods)
Transcribed Image Text:Renal Disease
A study was performed among patients with progressive
chronic kidney disease to assess the optimal time for the
![initiation of dialysis (Cooper et al. [22]). Patients were ran-
domized to either
i. an early start group, where dialysis was initiated when
their estimated glomerular filtration rate (GFR) was be-
tween 10.0 and 15.0 mL per minute per 1.73 m? of body
surface area or
ii. a late start group, where dialysis was initiated when
their GFR was 5.0 to 7.0 mL per minute per 1.73 m? of
body surface area.
The primary outcome was total mortality.
There were 404 patients assigned to the early start group,
of whom 152 died. There were 424 patients assigned to
the late start group, of whom 155 died over the same time
period. Patients were enrolled from July 2000 to November
2008 and were followed for 3 years.
10.86 What test can be used to compare the mortality
rates in the two groups?
10.87 Implement the test in Problem 10.86, and report a
two-sided p-value.
In planning the study it was anticipated that 400 subjects
would be enrolled per group and that the 3-year mortality
risk would be 36% in the late start group and 26% in the
early start group.
10.88 How much power would the study have if it had
occurred under the planned mortality rates and sample
size?
One issue is that not all the late start patients actually
started dialysis when their GFR was between 5.0 and 7.0.
Indeed, 75% of the late start patients initiated dialysis at a
GFR > 7.0 due to symptoms.
10.89 If we assume that these 75% of patients had a
mortality rate that was the average of the early start and
late start groups (i.e., 31%), then how much power did
the study actually have under the same assumptions as in
Problem 10.88?](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2Fdce824c0-dc16-4019-8115-50802f81c9ba%2F060fc990-8b90-4319-8d74-6cfe05896a1e%2Fye1yxx8_processed.png&w=3840&q=75)
Transcribed Image Text:initiation of dialysis (Cooper et al. [22]). Patients were ran-
domized to either
i. an early start group, where dialysis was initiated when
their estimated glomerular filtration rate (GFR) was be-
tween 10.0 and 15.0 mL per minute per 1.73 m? of body
surface area or
ii. a late start group, where dialysis was initiated when
their GFR was 5.0 to 7.0 mL per minute per 1.73 m? of
body surface area.
The primary outcome was total mortality.
There were 404 patients assigned to the early start group,
of whom 152 died. There were 424 patients assigned to
the late start group, of whom 155 died over the same time
period. Patients were enrolled from July 2000 to November
2008 and were followed for 3 years.
10.86 What test can be used to compare the mortality
rates in the two groups?
10.87 Implement the test in Problem 10.86, and report a
two-sided p-value.
In planning the study it was anticipated that 400 subjects
would be enrolled per group and that the 3-year mortality
risk would be 36% in the late start group and 26% in the
early start group.
10.88 How much power would the study have if it had
occurred under the planned mortality rates and sample
size?
One issue is that not all the late start patients actually
started dialysis when their GFR was between 5.0 and 7.0.
Indeed, 75% of the late start patients initiated dialysis at a
GFR > 7.0 due to symptoms.
10.89 If we assume that these 75% of patients had a
mortality rate that was the average of the early start and
late start groups (i.e., 31%), then how much power did
the study actually have under the same assumptions as in
Problem 10.88?
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