Questions tagged [hazard]
The hazard rate is the instantaneous rate at which units that have survived until time $t$ die at $t$. The hazard ratio is the ratio of 2 specified hazards.
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Am I able to calculate the p-value from hazard ratios and effect size? [duplicate]
I ran a Cox proportional-hazards (coxph) model on my data, which contains individuals with either a disease status1 or disease status2, and they have been administered either treatment A or treatment ...
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Survival analysis interaction interpretation: interaction is insignificant, but pairwise comparison does hold significance
I'm new with survival analyses, and have been breaking my head over this for a while, so I hope someone can explain this in a simple manner:
Variable
HR
Gender(Female)
1.391*
Treat (Yes)
0.544***
...
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In a survival meta-analysis shouldn't you use HR instead of RR?
I found this interesting survival meta-analysis: https://pubmed.ncbi.nlm.nih.gov/23216926/
Why do they compare OS between the different studies using RR and not HR?
Indeed the authors of this paper ...
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Cox regression hazard ratio (group 1 vs. group 4) changes calculation changes after combining group 2 and 3?
I am working on a project which involves fitting a Cox proportional hazard model to a time to event situation in SAS. We have the variables:
y - event or censor (0/1)
timeto - time to event y
x - ...
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Estimating probability of attack in Ukraine, given count data
I was looking at some attack count data in Ukraine for different days. The data is gathered from the ACCLED dataset, and there is a picture below. The picture shows individual attacks, but I can apply ...
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Competing Risks without Censoring
I am trying to estimate the probability that an entity goes from state $A$ to either state $B$, $C$, or $D$. The probability should be dependent on how long the entity has been in state $A$.
My data ...
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My teacher names hazard rates "probability". How can it be, since h(t) is unbounded as quotient?
Hazard rate, depending on the time scale, can be 0.1 or 100 or 1000. It's just a ratio. So why do people call it a "conditional probability"? Will I fail an exam, if I say that?
So, is this ...
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Statistical terminology: "hazard ratio" or "hazards ratio"
I have a question related to statistical terminology. More specifically, about the hazard ratio.
When describing the ratio between two hazard rates, we use the term "hazard ratio".
The term &...
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Is it possible to calculate number of events in each treatment arm if we have hazard ratio and number of patients in each treatment group
I have a question regarding calculating event numbers. I have a trial where the hazard ratio of treatment arm compared to control arm is 0.75 (95% CI: 0.59-0.96). I know the number of patients ...
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Extracting hazard ratio for subgroup from overall hazard ratio and hazard ratio of another subgroup?
Hi I have a relatively naive question here. Suppose in a clinical trial the overall HR of treatment A compared to treatment B is 0.66 (95% CI: 0.61 to 0.73). Now we perform a subgroup analysis of the ...
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Why don’t we just model the hazard ratio directly as a linear function of the covariates in a cox regression model?
Came across this question in my notes and I wish for some confirmation in my answer. The full question is : why don't we just model the hazard ratio $\phi= \frac{\lambda_{1}(t)}{\lambda_{0}(t)}$, ...
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What if proportional hazard assumption does not hold for a confounder in Cox PH model
If proportionality hazard assumption does not appear to hold for a covariate in the Cox PH model, is it a serious matter?
The covariate is included in order to adjust for potential confounding. I am ...
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How to simulate a time dependent variable on a existing dataset?
I made a coursera course abouth survival analysis. It uses a heart failure dataset for the examples. (That same dataset can be found on Kaggle https://www.kaggle.com/jackleenrasmybareh/heart-failure)
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Combining Time-Defined Hazard Ratios and Odds Ratios in Meta-Analysis
I am attempting to complete a meta-analysis of studies that variously report Odds Ratio of death at 30 days, and Hazard Ratios for death at 30 days.
All are reported as being close to 1 (range 1.2-1....
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Is it possible to calculate conditional PD / unconditional PD from Hazard Rate?
I'm just wondering that can I convert hazard rate to probability of default? Suppose I have the lifetime table data as per below:
Time
Total
Default
Non-Default
At Risk
0
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-
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356,335
1
5,587
1,...
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I cannot match the results of KaplanMeier and Nelson Aalen by hand
I have fitted both models by using lifelines python library.
The results of .event_table from both models are identically matched.
However, when I try to ...
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Survival function of accumulated hazard in Cox model
I have this setup:
Independent subjects following a Cox model
$$\lambda_i(t,X_i) = \lambda_0(t) \exp(X_i^T \beta ) $$
the observed right censored survival data $(T_i, \delta_i, X_i)$ are i.i.d. and $...
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Cumulative Incidence function and competing risks
Let $R_1,...,R_K$ be competing risks and put $T=\min(R_1,...,R_K)$ and $\delta = i$ if $T=R_i$. The cumulative incidence function is then defined as $F_i(t):=P(T\le t,\delta = i)$. The cause-specific ...
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Connecting Survival Analysis to Overall Predicted Survival Probabilities
I've got a question on combining survival analysis with predicted survival probabilities that I'm sure someone must have thought about, but I just can't find anything out there.
Imagine I have a good ...
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How does the hazard ratio change when the exposure is doubled?
I am a medical student who somehow ended up having to do a meta-analysis. I have no knowledge about statistics.
For example, if the cardiovascular mortality hazard ratio associated with a 5μg/m3 ...
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Survival data simulation based on confidence interval of Hazard ratio
I got a published hazard ratio (HR) of 0.464 with 95%CI as (0.337, 0.639) from a paper.
My question is
How can I get the distribution of the HR, so that I can check the different quantiles?
is that ...
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In Survival Analysis, does "Non - Cumulative" Hazard Exist?
In the context of Survival Analysis, I have seen that the standard (non-parametric) estimate of the Hazard Function is through the Nelson-Aalen Estimator :
As seen from this formula, the Nelson-Aalen ...
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Distance between hazard functions? [closed]
Let $F$ and $G$ two cumulative distribution functions with support on $(0,\infty)$. I know of many distances between distributions: Total Variation, Wasserstein, Hellinger, Kullback Liebler (...
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Plot of hazard ratio for primary endpoint and continuous covariate
I wonder if you could tell me the R code to use to obtain a graph similar to the one below. (from: https://www.nejm.org/doi/full/10.1056/NEJMoa1215740)
That is, I would like to graph the association ...
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How do you interpret outputs of Cox regression based on data type of an independent categorical variable?
I have the following data frame which consists of a grouping variable, as well as time ans status variables for survival analysis:
...
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Cumulative incidence vs Cumulative hazard: What's the difference?
Does anyone know what he difference between the 2 is? I want to calculate the cumulative incidence, but all I see is cumulative hazard in SAS.
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Hazard function of a simple system of components
I have been asked to complete these tasks, and a few more, but I am stuck somehow:
Figure 6 is the simple system above.
For task number 1: [DONE] I started by recognizing that the total survival time ...
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Cox Proportional Hazards Interaction Hazard Ratios
I am looking at the interaction of dose (continuous with mean=2241 and sd=949.4) and cause of death (values of 0 or 1) in a survival analysis. The interaction is tending towards significance, and ...
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Why are confidence intervals of hazard ratios not symmetric?
My understanding is that the confidence interval for a hazard ratio should be symmetrical about the mean (the distance between the lower limit and the mean is the same as the distance between the mean ...
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Calculate the standard deviation from a hazard ratio's confidence interval
I often come across hazard ratios and their confidence intervals in the published literature on clinical trials. I would like to calculate the standard deviation from these confidence intervals for ...
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Meta analysis Hazard Ratio with small number of studies (n=2)
I am doing a fixed effect meta-analysis pooling hazard ratios from 2 very similar cohorts.
I understand that the inverse variance method is most commonly used to pool HR, however I also read that this ...
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Mathematical connection between hazard functions for e.g. Cox models and expected values in GLMs
I intuitively understand why the hazard function is interesting to link to patient attributes, as explained in this answer. However, is there a mathematical reason this is done? I'm particularly ...
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Why does random survival forest use Cumulative Hazard Function to calculate C Index?
I am working with Random Survival Forests and I found out in the documentation that it uses Sum of Cumulative Hazard Function to define a worse predicted outcome, which is subsequently used to compute ...
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Presenting raw hazard ratios, not log(hazard ratio), in forest plot for meta-analysis using metafor
I'm trying to perform a meta-analysis in R with metafor of trials for which the hazard ratios(HR) and 95% CI are available as outcomes.
I am aware that I have to use log(HR) for calculation, but I ...
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How to get beta coefficients for reference group in Cox proportional hazards regression model survival analysis (R or other)?
The model was calculated using the coxph and survival functions from the survival package (R). Each of nine variables was set as categorical with a reference strata.The criterion was the survival ...
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How to find hazard function from a survival curve
I have just started learning survival analysis. And i came across the survival curves and graphs and hazard function. Help me answer with the following question: Given a well structured graph of ...
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Merging survival data with time varying covariates
In merging the data in R the censored observations are merged well but the observed subjects are not. For example, the second subject had an event at time 0.546. How can I merge the time varying ...
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How to find out hazard ratio and confidence interval from LASSO cox regression ans plot momogram in R?
I am working on a prognostic model based on time to event endpoint. The training data consists of 800 participants and test data around 400. The number of variables is 21. I was using glmnet package.
...
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How to plot the hazard ratio of a categorised variable in its original continuous scale? take BMI for an example
I have BMI divided into quartiles. I fitted two cox regression models that included BMI as a categorical and continuous variable respectively. Now I want to plot the hazard ratio of categorical BMI ...
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Network meta-analysis with trials of different follow-up time [closed]
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I am trying to do a network meta-analysis, and calculating anticipated absolute differences, I have seen other papers generating anticipated absolute differences for treatment for x number of years. ...
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Regression on time passed until certain threshold is "re-reached"
I would like to test the time/duration it takes for a certain variable to reach a certain level (e.g. time passed after companies reach a pre-crisis level at point x again in their recovery process ...
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Can one compare Hazard Ratio and Average Hazard Ratio?
I would like to compare three predictors of survival by comparing three cox regression models.
One model violates the PH assumption which brought me to weighted cox regression as implemented by ...
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How to sample non-event data for survival analysis
I am building a model to predict customer churn using survival analysis, COX regression in particular. While it is pretty straight forward to collect churn events, it is a little tricky to sample for ...
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Cox PH model and regression with log-log link function: is there a connection?
In this post: interpreting estimates of cloglog logistic regression, I read that when interpreting the results of a regression with a log-log link function, the exponent of the estimated coefficient ...
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Computing Chi-square values from Schoenfeld residuals
Based on page 164-165 of [Collett:Modelling Survival data in medical research (Third edition-2014)] the Schoenfeld for individual test and for global test can be obtained as follows[1].
However, ...
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Hazard function to PDF computation [closed]
I am trying to formulate the computation between the Hazard function and probability density function.
Given an example: pdf_arr = [0.2, 0.2, 0.2, 0.2, 0.2].
My ...
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Intuition behind Weibull distribution?
I don't understand the physical meaning of Weibull distribution's $k$ parameter. Here is a simplified formula of cumulative probability function of Weibull in the simplest form:
$$p(\xi \geq x) = e^{-(...
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Calculate the confidence interval of a Hazard Ratio from the ones of the survival
I have 2 populations with their survival at n years and their 95% confidence interval.
Under the assumption of exponential distribution, the hazard ratio can be ...
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Stratified KM curve plot for estimation of proportional hazards assumption violation
I am reading a paper that attempts to investigate time varying covariates in Cox proportional hazard model for breast cancer patients. I read that we can plot stratified KM curves for two groups of ...
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