A study is conducted to estimate survival in patients following kidney transplant. Key factors that adversely affect success of the transplant include advanced age and diabetes. This study involves 25 participants who are 65 years of age and older and all have diabetes. Following transplant, each participant is following for up to 10 years. the following are times to death, in years, or the time to last contact (at which time the participants was known to be alive). Deaths: 1.2, 2.5, 4.3, 5.6. 6.7, 7.3 and 8.1 years Alive: 3.4, 4.1, 4.2, 5.7, 5.9, 6.3, 6.4, 6.5, 7.3, 8.2, 8.6, 8.9, 9.4, 9.5, 10, 10, 10 and 10 years Interval in Years Number At Risk During Interval, Nt Average Number At Risk During Interval, Nt*=Nt-Ct/2 Number of Deaths During Interval, Dt Lost to Follow-Up, Ct Proportion Dying qt = Dt/Nt* Proportion Surviving pt = 1-qt Survival Probability St = pt*St-1 0-2 2-4 4-6 6-8 8-10 Use the Kaplan-Meier approach to estimate the survival function. Referring to the graph below: What is the probability of surviving 6.5 years? A. None B. 0.85 C. 0.60 D. 0.90 Patients have an 85% chance of surviving how many years? A. 6.0 B. 4.25 C. 3.2 D. 5.5 Time, Complete the table below Years Number at Risk Nt Number of Deaths Dt Numbers Censored Ct Survival Probability St+1= St*((Nt-Dt)/Nt) 0 25 1.2 2.5 3.4 4.1 4.2 4.3 5.6 5.7 5.9 6.3 6.4 6.5 6.7 7.3 8.1 8.2 8.6 8.9 9.4 9.5 10.0 Interval in Years Number At Risk During Interval, Nt Average Number At Risk During Interval, Nt*=Nt-Ct/2 Number of Deaths During Interval, Dt Lost to Follow-Up, Ct Proportion Dying qt = Dt/Nt* Proportion Surviving pt = 1-qt Survival Probability St = pt*St-1 0-2 2-4 4-6 6-8 8-10 Solution Probability of surviving 6.5 years: A. None of the above 85% chance of surviving: B. 4.25 years.

1. A study is conducted to estimate survival in patients following kidney transplant. Key factors
that adversely affect success of the transplant include advanced age and diabetes. This study
involves 25 participants who are 65 years of age and older and all have diabetes. Following
transplant, each participant is following for up to 10 years. the following are times to death, in
years, or the time to last contact (at which time the participants was known to be alive).
Deaths: 1.2, 2.5, 4.3, 5.6. 6.7, 7.3 and 8.1 years
Alive: 3.4, 4.1, 4.2, 5.7, 5.9, 6.3, 6.4, 6.5, 7.3, 8.2, 8.6, 8.9, 9.4, 9.5, 10, 10, 10 and 10 years
Interval in Years
Number At Risk During Interval,
Nt
Average Number At Risk During Interval,
Nt*=Nt-Ct/2
Number of Deaths During Interval,
Dt
Lost to Follow-Up, Ct
Proportion Dying
qt = Dt/Nt*
Proportion Surviving pt = 1-qt
Survival Probability
St = pt*St-1
0-2

2. 2-4
4-6
6-8

3. 8-10
Use the Kaplan-Meier approach to estimate the survival function.
Referring to the graph below:
What is the probability of surviving 6.5 years?
A. None
B. 0.85
C. 0.60

4. D. 0.90
Patients have an 85% chance of surviving how many years?
A. 6.0
B. 4.25
C. 3.2
D. 5.5
Time,
Complete the table below
Years
Number at Risk
Nt
Number of Deaths
Dt
Numbers Censored
Ct
Survival Probability
St+1= St*((Nt-Dt)/Nt)
0
25
1.2

5. 2.5
3.4
4.1
4.2

6. 4.3
5.6
5.7
5.9

7. 6.3
6.4
6.5
6.7

8. 7.3
8.1
8.2
8.6

9. 8.9
9.4
9.5
10.0

10. Interval in Years
Number At Risk During Interval,
Nt
Average Number At Risk During Interval,
Nt*=Nt-Ct/2
Number of Deaths During Interval,
Dt
Lost to Follow-Up, Ct
Proportion Dying
qt = Dt/Nt*
Proportion Surviving pt = 1-qt
Survival Probability
St = pt*St-1
0-2
2-4

11. 4-6
6-8

12. 8-10
Solution
Probability of surviving 6.5 years: A. None of the above
85% chance of surviving: B. 4.25 years