Multicentre trials meta-analysis

A data set consisting of a series of results by treatment for a number of centres is closely analogous to one consisting of a number of results by treatment for a number of trials. Accordingly, many similar issues to those that arise in meta-analysis arise in the analysis of multicentre trials, although traditions in the two cases are rather different. Hence, there may be some value in studying this chapter and Chapter 16 on meta-analysis together. 

Choices between fixed- or random-effect estimators arise wherever we have data sets with multiple levels within the experimental units for example, patients within trials for a meta-analysis, episodes per patient for a series of n-of-1 trials or patients within centres for a multicentre trial. The issue is an extremely complex one and it is difficult to give hard and fast rules as to which is appropriate. 

There are a number of techniques which may be used. If the studies involved have a similar structure and use the same outcome variables and the meta-analyst has access to the original data (which is usually the situation of the drug developer), then an analysis of these raw data is both possible and (almost invariably) desirable. This has been referred to as a type A meta-analysis (Senn, 2000b). The situation is then very like that in a multicentre trial, with trials rather than centres forming the strata. In principle all the controversies, issues and difficulties which arise with multicentre trials may be attendant on such an analysis but there is no particular reason why new difficulties should present themselves. 

Table 2.1.2. Complication rates in RFA of solid organs in the abdomen derived from two multicentre trials and a comprehensive meta-analysis (Mulier et al. 2002 Livraghi et al. 2003 Rhim et al. 2003)...

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