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From |
"Tom Trikalinos" <ttrikalin@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: Meta-analysis |

Date |
Mon, 17 Mar 2008 14:52:59 -0400 |

yup, this is why this is a big topic ;-) ... with no easy answer... conducting and interpreting sparse event meta-analysis is challenging... especially when you find a difference in the end. [and on top of that, as Ingram complains, no one uses the angular (tukey-freeman) transformation ;) ] t On Mon, Mar 17, 2008 at 1:54 PM, Marcello Pagano <pagano@hsph.harvard.edu> wrote: > Welcome to one of the few areas in statistics where people promote > throwing data away with impunity. One could say that whether you > discard experiments where there are no events on either arm, or not, > depends which side of the argument you are on. Since no events on > either arm is evidence towards equality of the two arms, then throw the > data away if you are trying to show a difference :-) Otherwise, why > throw the data away? > > The usual reason proffered for discarding the data is that it is > embarrassing when looking at odds ratios to have to divide zero by zero. > But the question you have to ask yourself is why are you looking at odds > ratios? If you have to, for example if you have a case-control study, > then you have a problem, otherwise stay clear of odds ratios and you > won't have a problem if you use appropriate methods for analysis. > > m.p. > > > > On 3/17/2008 1:24 PM, Tom Trikalinos wrote: > > this is a big topic. > > see for example: > > > > Stat Med. 2007 Jan 15;26(1):53-77. Much ado about nothing: a > > comparison of the performance of meta-analytical methods with rare > > events. Bradburn MJ, Deeks JJ, Berlin JA, Russell Localio A. > > > > Stat Med. 2004 May 15;23(9):1351-75. What to add to nothing? Use and > > avoidance of continuity corrections in meta-analysis of sparse data. > > Sweeting MJ, Sutton AJ, Lambert PC. > > > > and quite a few other papers that are out there. The ones discussing > > the recent rosiglitazone meta-analysis are also relevant. Do a PubMed > > search if you have not already. > > > > My take: Assuming you do not go Bayesian and that you use the typical > > garden variety meta-analysis methods: > > > > 1. Random effects per Der Simonian and Laird are probably a no for > > main analyses (biased tau^2 in simulation studies). > > 2. Peto OR seems to do well in terms of bias and coverage > > probabilities for the CI (!). > > 3. Mantel-Haenszel (MH) OR seems to do well, I presume the same for RR > > though i think this is not as clear, or so i remember. > > 4. M-H RD is reported to give somehow biased estimates and conservative CI > > > > 5. If you use multiplicative effect sizes - e.g. an OR I would > > calculate main analyses without 0% vs 0% studies, then add them in in > > a sensitivity analysis > > > > All the above allowing for the caveat that one an operational > > knowledge of the relevant methods literature and knowledge of which > > methods need fudge factors to correct for 0 cells... > > > > hope this helps > > > > tom > > > > > > > > On Mon, Mar 17, 2008 at 12:42 PM, Sripal Kumar <sripalkumar@gmail.com> wrote: > > > >> I was wondering what are your thoughts on meta analysis of trials with > >> limited number of events. Should studies with no events be censored > >> from the analysis? > >> > >> Any input is highly appreciated. > >> thanks, > >> Sripal. > >> > * > * For searches and help try: > * http://www.stata.com/support/faqs/res/findit.html > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/support/faqs/res/findit.html * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**References**:**st: Meta-analysis***From:*"Sripal Kumar" <sripalkumar@gmail.com>

**Re: st: Meta-analysis***From:*"Tom Trikalinos" <ttrikalin@gmail.com>

**Re: st: Meta-analysis***From:*Marcello Pagano <pagano@hsph.harvard.edu>

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