[R-meta] It is possible to calculate the Hazzard Ratio and 95% CI on different reference groups from summary available data?

[Mario Petretta]

Sorry for misspelling..Hazard Ratio 

Inviato da iPad

> Il giorno 2 lug 2019, alle ore 17:55, Prof. Mario Petretta <petretta using unina.it> ha scritto:
> 
> Dear mailing list members
> 
> I am doing a meta-analysis on the prognostic value of diastolic blood
> pressure (BP). 
> A study reported the unadjusted hazard ratio (from Cox regression) for three
> categories: 
> 
> 1)    BP under 90 - hazard ratio 1 (reference)
> 2)    BP 90 - 99 - hazard ratio 1.89 (95% CI 1.09, 3.33)
> 3)    BP over 100 - hazard ratio 3.03 (95% 1.67, 5.56)
> 
> It is possible to combine these hazard ratios and the 95% confidence
> intervals for three categories in two categories, considering together the
> reference category and the second category as a new reference vs the third
> category? 
> 
> A more general question is: It is possible to convert hazard ratios and 95%
> CI for 3 or more categories to a hazard ratio for 2 categories, changing the
> reference category? 
> 
> Thanks for your attention.
> 
> 
> ___________________________________________
> Mario Petretta, MD, FAHA
> Associate Professor of Internal Medicine
> Department of Translational Medical Sciences
> Naples University "Federico II" - Italy
> 
> 
>