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I've recently calculated a hazard ratio doing a multi variable Cox regression analysis (Kaplan Meier) for an assignment. Part of my feedback was to adjust the hazard ratio to a 'crude ratio'.

How do I do that? I'm using SPSS 19/PASW.

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up vote 4 down vote accepted

Actually, it sounds like the hazard ratio you obtained was the adjusted ratio, whereas by definition the crude ratio has no adjustment for covariates.

When you did your multivariable Cox regression, you included some covariates in the model, and the crude ratio would be the hazard ratio without these covariates included in the model.

To get this, you can re-run your Cox regression without including the covariates.

I would recommend reading the following link: http://faculty.chass.ncsu.edu/garson/PA765/cox.htm

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Thanks for your reply. Do you mean only including a single covariate? A presume so, because if I don't include any covariates I don't see where I should read actual crude ratio in the output? (BTW: I read the fine article, but I didn't read anything in there particularly about crude ratios) – Alex Jun 27 '11 at 13:13
Unfortunately I'm not an SPSS user, but I presume this was a Cox regression with two groups and one or more covariates that you were adjusting for. What you need to do is just run the regression using only the groups and leave out the adjustment for any covariates. This will give you the crude model. – pmgjones Jun 27 '11 at 18:17
OK, great. Thank you again! ;) – Alex Jun 28 '11 at 7:57

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