[R-meta] Fwd: meta analysis package "metafor" --- one group survival outcome?

Wed, Jun 28, 2017 7:57 AM

A method for pooling KM estimates (at a particular time point) across multiple studies is described in:

Coplen, S. E., Antman, E. M., Berlin, J. A., Hewitt, P., & Chalmers, T. C. (1990). Efficacy and safety of quinidine therapy for maintenance of sinus rhythm after cardioversion: A meta-analysis of randomized control trials. Circulation, 82(4), 1106-1116.

In essence, we can just pool the KM estimates in the usual manner (FE/RE model). The variance of the KM estimates can be computed using Greenwood's formula (https://en.wikipedia.org/wiki/Kaplan%E2%80%93Meier_estimator#Statistical_considerations).

You can do the pooling with metafor (or other packages). In metafor, just use rma(yi, vi) where yi are the KM estimates and vi the corresponding variances.

This approach uses the KM estimates directly. Indeed, the sampling distribution of KM estimates may not be normal, but that may not be a major issue unless you suspect that the underlying true survival rates are close to 0 or 1.

As for your question about a sample size calculation -- I am not quite sure what you are after. You (typically) do not have any influence on the number of studies included in a meta-analysis or the sample sizes thereof. So what are you trying to accomplish here?

Best,
Wolfgang

[R-meta] Fwd: meta analysis package "metafor" --- one group survival outcome?

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