All Questions
11 questions
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Interaction effects in a Cox model
In regression models, usually a (descriptive) indicator of an interaction effect can be plotted via a plot with x-axis with the potential interaction variable (e.g., gender) and the outcome variable ...
- 133
2
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2
answers
124
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Interpretation of Interaction when the results in one of the two groups is not statistically significant
Here is the question. Suppose we have a drug A, and we have conducted a RCT evaluating the risk of death in patients randomised to receive ...
- 706
0
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0
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61
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3 terms interaction in Cox PH model
'''
coxph(formula = Surv(time, hyper) ~ age + drink + smoke + sodium * tchl * BMI, data = male)
coxph(formula = Surv(time, hyper) ~ age + drink + smoke + sodium * tchl * BMI, data = female)
The 3-...
- 37
3
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2
answers
3k
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Difference in stratification, interaction and subsetting Cox Survival Regression
I'm struggling to understand the actual differences in these three approaches that came to my mind.
The problem is: I want to analyze the impact of age on mortality in my cohort. However, I want to ...
- 706
1
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1
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106
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If we say "Survival difference adjusted for covariates" do we mean just additive adjustment, or allow also the interactions?
Let's make it independent from any statistical package, so I will provide just numbers for the illustration. Maybe this give you some clues.
I want to compare two survival curves, for group A and B.
...
- 11
1
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1
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143
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Presentation of a 3x3 categorical interaction for Cox proportional hazards regression using RMS package
I wanted to verify my presentation of a 3x3 interaction of two categorical variables var1 (exposure of interest) and var2 (effect modifier of interest) using the rms...
- 11
1
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1
answer
771
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Interaction not significant in Cox regression model?
I ran a cox model with an interaction between two categorical variables (sex and treatment group) included like:
...
- 381
3
votes
2
answers
3k
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Why and how does adding an interaction term affects the confidence interval of a main effect?
I was wondering why, in a regression model including an interaction term, the confidence interval of one of the main effects becomes wider.
Consider this Cox regression, where the variable IR_BMI27 ...
- 305
1
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1
answer
2k
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Interpretation Interaction in Cox Regression
I am estimating a discrete choice model with the help of cox regression in SPSS.
I would like to interact two continuous predicting variables.
The main effect of one of the ineracting variables is ...
- 11
2
votes
1
answer
108
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R adds unexpected variable to interaction model
Not sure if this is more of a programming question (in which case please move to stack overflow) or a statistical model question (in which case, please read on!)
I'm exploring a data set and doing ...
- 10.2k
1
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2
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478
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Should I keep the interaction term?
I am doing research on mortality. I am running Cox regression and I am adjusting for 40 variables which are proven in the literature to be related with mortality. My main exposure is X. In my final ...
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