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    Patient-year Incidence rates comparisons and p value

    Dear all, I would like to statistically compare two incidence rates from two different groupes. I found the Incidence rate difference (IRD) formula from "Sahai and Kurshid, 1996". The way to calculate (with examples) are presented in the following page ...
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    Confidence interval for person time incidence rate

    Dear everyone, I would like to estimate a 95%CI of person time incidence rate (as 45 death per 10,000 person year) Anyone knows a way to estimate it ? Same question for Kaplan Meier estimate.. Thanks a lot for your help!
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    U shaped curve modelling

    Hello, Someone knows how to modelize and test a U shaped curve and if there is a specific procedure in SAS? Thanks for your help!
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    Odds ratios lower than 1 for continous variable

    Lets says you want to check the effect of age on a specific event. In the univariate model : event = age, the odds is significantly lower than 1 which seems to show a 'protective impact' of age on this event (age increase -> probablity of event decrease) However, after checking, average of...
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    Incidence rate and Kaplan Meier

    Hello, I have a question about what we call "incidence rate" at the end of a longitudinal study. If there are a number of censored data, how do you calculate this IR. Is that the same calculation as Kaplan Meir estimate at the end of the study, or there is another way to calculate it...
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    multi level categorical variable in a cox model

    Hello everyone, I would like to know which kind of test of significance do you use for categorical variables with more than two levels in a COX model (as 3 or 4 levels). SAS supply type 3 test but I don't understand exactly what does that means. And a second question : What can we do to...
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    plots for hazard ratios / continuous variables

    Hello everyone, Somebody knows which kind of plots could I create to display a set of hazard ratios for continuous variables. I used to use forest plots for groups of comparison, but it's more suitable for categorical variables. Thanks for your help
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    COX models and continuous variables

    Hello everyone. I have a simple and basic question about cox model. When I introduce a continuous variable in the model, the hazard ratio assessed for this variable relates the increase (decrease) of the risk after an increase of one unit of the continuous variable. How to extrapolate for more...