Hazards Regression
Survival
Log-rank test
Atopic dermatitis and osteoporosis
Survival Analysis
Time Intervals |
N Alive |
NDied |
Proportion Died |
Proportion Survived |
Cumulative Survival |
6 months |
169 |
22 |
0.1152 |
0.8848 |
0.8848 |
12 months |
144 |
17 |
0.1056 |
0.8944 |
0.7914 |
24 months |
87 |
31 |
0.2627 |
0.7373 |
0.5835 |
36 months |
36 |
10 |
0.2174 |
0.7826 |
0.4566 |
Log-rank test
P <0.0001, indicates a significant difference in the patient's survival in the 4 clinical stages.
Clinical Stage | Survival at 6 Months | Survival at 12 Months | Survival at 24 Months | Survival at 36 Months | Median Survival |
Stage 1 | 0.9327 | 0.9186 | 0.8376 | 0.7908 | |
Stage 2 | 0.8980 | 0.7906 | 0.5124 | 0.3933 | 25.4600 |
Stage 3 | 0.8696 | 0.7391 | 0.5593 | 0.4187 | 31.9700 |
Stage 4 | 0.6667 | 0.4000 | 0.0667 | 0 | 7.2900 |
Yes, this agrees with the plot and statistical test. The survival rates are different for patients in various clinical stages.
Stage 2 – 3.739. Death risk is 3.739 times higher in Stage 2 compared to Stage 1.
Stage 3 – 3.659. The risk of death is 3.659 times higher in Stage 3 compared to Stage 1.
Stage 4 – 13.851. The risk of death is 13.851 times higher in Stage 4 compared to Stage 1.
This agrees with the previous findings.
Stage 2 – 3.848. The risk of death is 3.848 times higher in Stage 2 compared to Stage 1.
Stage 3 – 4.115. The risk of death is 4.115 times higher in Stage 3 compared to Stage 1.
Stage 4 – 15.893. The risk of death is 15.893 times higher in Stage 4 compared to Stage 1.
The risk of death is 1.070 times higher among patients who don’t have insurance covers.
The risk of death is 1.459 times higher for Black patients.
The risk of death is 1.436 times higher for Hispanic patients.
Increase in the Annual hospital patient volume by increasing the risk of death by 0.981.
The confounders increase the risk ratios between clinical stage and time to mortality.
Code for Survival
*Upload the dataset and run proc import statement*;
*Kaplan-Meier Method for time to mortality;
ods graphics on;
proclifetest data=work.mortality plots=s(atrisk=0 to 42 by 6);
timedx_lastcontact_death_months*mortality(0); label dx_lastcontact_death_months='Months from Diagnosis';
run;
ods graphics off;
*Kaplan-Meier Method for time to mortality by clinical stage (1, 2, 3, and 4);
ods graphics on;
proclifetest data=work.mortality plots=s(nocensoratrisk=0 to 36 by 6) maxtime=36;
timedx_lastcontact_death_months*mortality(0); label dx_lastcontact_death_months='Months from Diagnosis';
strataClin_Stage; label Clin_Stage='Clinical Stage';
run;
ods graphics off;
*Univariate Cox Proportional Hazards Model for Clinical Stage*;
procphreg data=work.mortality; class clin_stage(ref='1') /param=reference;
modeldx_lastcontact_death_months*mortality(0) = clin_stage /rl;
run;
*Multivariable Cox Proportional Hazards Model for Clinical Stage*;
procphreg data=work.mortality; class clin_stage(ref='1') /param=reference;
modeldx_lastcontact_death_months*mortality(0) = clin_stagenoinsur black hispanic volume /rl;
run;
Information on Study Data, including Data Dictionary:
NAME: Cancer Mortality Data (Mortality.csv)
SIZE: 200 observations, 8 variables
DATA DICTIONARY:
Variable Label | Variable |
ID | Patient ID (1-200) |
Dx_LastContact_Death_Months | Months from cancer diagnosis to death or date of the last follow-up |
CLIN_Stage | Clinical Stage (1-4) |
Volume | Annual hospital patient volume |
Noinsur | Patient insurance status (0=no insurance, 1=insurance) |
Black | Black race (0=no, 1=yes) |
Hispanic | Hispanic ethnicity (0=no, 1=yes) |
Mortality | Survival status (0=alive, 1=dead) |