+ Reply to Thread
Results 1 to 7 of 7

Thread: Can I combine univariate and multivariate HR?

  1. #1
    Points: 40, Level: 1
    Level completed: 80%, Points required for next Level: 10

    Posts
    4
    Thanks
    2
    Thanked 0 Times in 0 Posts

    Can I combine univariate and multivariate HR?




    Hi guys.
    I'm doing a meta-analysis of survival based on a blood marker, and not all the studies have provided a multivariate hazard ratio. Some have given a univariate hazard ratio (usually where it is not significant) and I would like to put them into the random effects analysis also. Should I do this, or is there another way to incorporate the studies?
    Thanks

  2. #2
    Omega Contributor
    Points: 38,396, Level: 100
    Level completed: 0%, Points required for next Level: 0
    hlsmith's Avatar
    Location
    Not Ames, IA
    Posts
    7,001
    Thanks
    398
    Thanked 1,186 Times in 1,147 Posts

    Re: Can I combine univariate and multivariate HR?

    Theoretically would the missing control variables impact the effect of the variable of interest. So is there any omitted variable bias resulting from say not controlling for an interaction, confounding, or mediation variable. Or could some variables be correlated, but are excluded, so SEs may be more inflated in multivariate analyses than the univariate?


    What hypothetical threats could exist?


    P.S., I am not overly familiar with MA using HR results, there could be other issues.
    Stop cowardice, ban guns!

  3. #3
    Points: 40, Level: 1
    Level completed: 80%, Points required for next Level: 10

    Posts
    4
    Thanks
    2
    Thanked 0 Times in 0 Posts

    Re: Can I combine univariate and multivariate HR?

    Thanks for the response.
    I guess you are right, I cannot control for the influence of the other variables

  4. #4
    Omega Contributor
    Points: 38,396, Level: 100
    Level completed: 0%, Points required for next Level: 0
    hlsmith's Avatar
    Location
    Not Ames, IA
    Posts
    7,001
    Thanks
    398
    Thanked 1,186 Times in 1,147 Posts

    Re: Can I combine univariate and multivariate HR?

    That is given there is actually a plausible relationship. If the other variable are just being controlled for then you could have a little wiggle room. Not sure of the protocol how to handle this in MA, but you could always run the MA with and without them. Do the univariate studies list in there limitations why or why not the control variables may have been used.


    Are any of these randomized control trials?
    Stop cowardice, ban guns!

  5. #5
    Points: 40, Level: 1
    Level completed: 80%, Points required for next Level: 10

    Posts
    4
    Thanks
    2
    Thanked 0 Times in 0 Posts

    Re: Can I combine univariate and multivariate HR?

    They are not RCT's, mainly observational case series looking at various markers for prognosis (tumour size etc). The univariate HRs I want to include are all for non significant variables and hence their lack of further analysis in the original studies.

  6. #6
    Omega Contributor
    Points: 38,396, Level: 100
    Level completed: 0%, Points required for next Level: 0
    hlsmith's Avatar
    Location
    Not Ames, IA
    Posts
    7,001
    Thanks
    398
    Thanked 1,186 Times in 1,147 Posts

    Re: Can I combine univariate and multivariate HR?

    If they come from observational studies, well that may mean the underlying patient baseline characteristics may differ between studies and univariate estimates COULD possibly be biased, depending on what they are for in particular. An example, you may not be controlling for treatment differences, type of hospital or interventions, comorbidities, etc. The variable of interest may be influenced by these things and not controlling for them, given they could differ between sample (e.g., study), may be a potential issue.
    Stop cowardice, ban guns!

  7. The Following User Says Thank You to hlsmith For This Useful Post:

    ngmowbray (02-22-2017)

  8. #7
    Points: 3,006, Level: 33
    Level completed: 71%, Points required for next Level: 44

    Posts
    177
    Thanks
    1
    Thanked 29 Times in 29 Posts

    Re: Can I combine univariate and multivariate HR?


    The first question you should ask is how many studies do you have (i.e. if you have 50 studies without the univariate studies, its probably not worth inclusion and having a reviewer get upset over it...which they probably will for the reasons raised thus far).

    At worst, if you want to include them, they should be flagged with a dummy variable in your analysis. Its very likely that these univariate studies will fall within the normal distribution of your meta-analysis. So when you run your meta-regression, include a dummy variable that signifies "univariate studies" and include that in your results.

  9. The Following User Says Thank You to the42up For This Useful Post:

    ngmowbray (02-22-2017)

+ Reply to Thread

           




Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts






Advertise on Talk Stats