cox regression

  1. M

    How to predict overall survival (Cox) based on a population?

    Hi, there! First of all, I am quite excited about having found this forum, and look very much forward to learning from here. (: Say I want to devise a score index for predicting patient overall survival (OS) based on a handful of co-variates, what would be the best way to do it? Briefly, I...
  2. F

    Cox regression results interpretation

    Hi! I am currently working on a statistical analysis on a prospective cohort population. We are looking at a specific protein concentration at baseline and relate this to a certain outcome. The outcome group have been matched with twice as many control individuals from the same cohort. The...
  3. P

    Should IRRs and HRs always be equal?

    I am running an analysis in a large population registry where individuals enter and leave the dataset at different time points. When i estimated the IRR between two distinct groups and a health outcome, and then a HR, I am finding a small difference (IRR 2.18, HR 2.01). Shouldn't they have...
  4. H

    Bootstrapping for cox regression analysis

    Hello, I have categorical data (high/low) on a protein which I am investigating its potential role as a prognostic utility. I have run a cox regression with the categorical data and 3 year survival as outcome (dead/alive) I get a significant results (attached). I then ran...
  5. R

    Cox Regression with missing values

    Very grateful for any advice. I'm trying to perform Cox regression on a data set with multiple random missing values. SPSS is my go-to software, but the Cox regression algorithm applies LISTWISE deletion to all cases with missing values, resulting in omission of >30% of the cases. I'd rather...
  6. M

    Study population mean as a reference for COX-regressions in SPSS

    Hi! I'm a medical student doing my master thesis. In my analysis I intend to compare two different systems for subclassing stroke as per ethiology. I have 1300 patients subtyped according to both these systems. I also have information of longterm outcome for these patients in terms of...
  7. V

    Cox regression survival analysis

    Hi, I am currently undertaking my dissertation and wondered if you could help me with some data analysis from one of my studies. The study indicates that they use Cox regression for survival analysis Results indicate that for group differences in depressive episodes the hazard ratio =0.38 95%...
  8. R

    Cox regression application in business/finance

    Hi all, I hope this is the right forum to ask as cox regression is usually use by bio-statisticians. My research is about companies which producing either product A or product B. This companies will either distress (1) or stay healthy (0). The time of production for product A/B are...
  9. I

    Cox/ Binomial Regression: How to reconcile Non-significant model with significant IVs

    Hello I'm been performing some survival and regression analyses corresponding to an event of interest being death or a certain surgical procedure, namely a shunt revision for pediatric neuro-surgical patients. I know how to properly execute the procedures w/i SPSS and am familiar w/ the...
  10. M

    How to stratify an additive hazards model?

    Hi, I am trying to conduct a stratified additive hazards model (Aalen’s additive model). I am using Stata 12.1. The stata syntax for the Aalen’s additive hazards model is stlh. I have pooled a number of cohorts and would like to calculate the coefficients for risk factors for the...
  11. R

    Which regression model should I apply?

    Dear all, I want to do an empirical analysis on the risk-return characteristics of venture capital investments across industries applying a discrete binomial tree model. Therefore, I want to do a multiple regression. However, I am struggling with the decision which regression model I should...
  12. D

    SPSS Survival analysis - Should I split data file by groups or use covariates instead

    Hello! I have to assess different factors affecting the survival after transplantation. Can you advise me which is better (or more correct)? - to split the data file by groups (for example type of disease - malignant or non-malignant) and analyze the effect of other factor/s (e.g. HLA...
  13. K

    Cox regression model, hazard ratio , using categorical data.

    Hello everyone! I am studying the effect of 8 arm of treatments on a cohort of 80 mice. The variable I have are: time status and arm of treatment. I generated KM curves and obtained by log rank test both a general p.value and pairwise comparisons between couples of curves. Then, I needed...
  14. J

    How do I calculate time dependent covariates in SPSS?

    I am new to survival analysis and would appreciate some help! (I'm from psychology, and my discipline does not tend to conduct survival analysis) At the moment, I am having difficulty calculating time dependent variables in cox regressions. Intro to my data: 7 waves of data V1: event...
  15. A

    Modelling this non-linear relationship- please help

    Hi All, I'm using usual Cox regression where my outcome is time to a binary event. My variable of interest (a biological marker) appears to show a non-linear relationship with the outcome. I categorised it as 10 quantiles with the 6th as the reference category. The HR (with 95% CI) for...
  16. G

    Help - Moderation with dummies in Cox Regression

    Hi, I am currently working on my masters thesis. I am testing how team change following an acquisition affects the survival of the acquisition itself (expecting a negative effect) and to do so I am using a Cox survival analysis. I have 2 moderators which a are 1/0 dummies, one is...
  17. A

    Another, more difficult Cox Regression/Hazard Ratio interpretation question

    So, for an assignment, we were given this data taken from the Stanford Heart Study from 1978 or so: I used equal signs because I thought dashes might be confusing. They haven no mathematical function in the following 'tables' The variables in question are: Age in years in reference to age 48...
  18. A

    Cox Regression/Hazard Ratio interpretation question

    Hi, all. I've done all the coding already for this, I just don't know how to interpret it. For an assignment, we were given this data taken from the Stanford Heart Study from 1978 or so: I used equal signs because I thought dashes might be confusing. They haven no mathematical function in the...
  19. A

    Question about Hazard Ratio Interpretation

    Hi, all. I've done all the coding already for this, I just don't know how to interpret it. For an assignment, we were given this data taken from the Stanford Heart Study from 1978 or so: I used equal signs because I thought dashes might be confusing. They haven no mathematical function in the...
  20. S

    Compare coefficients across Cox regressions to conclude x1 is more harmful than x2?

    Hi, Our question is regarding to comparison of effects of different variables in survival analysis. Usually, the Cox model tests the effects between different levels of a variable e.g. between treatment and placebo, but would it also address the effects between variables? We keep...