Today, clinicians are more and more involved in conducting and evaluating
results of diagnostic tests, procedures and clinical trials. Clinicians
realise that to do this properly it is necessary to be aquainted with the main
features and methodology of statistics applied to these areas.
During the last few years, although there has been a slow progress towards an
evidence based practice of medicine, the current situation is far from
satisfactory.
Among the principal reasons why the slow progress is being made is the lack of
knowledge in the use of mathematical and statistical tools and thus the
tendency to avoid using these.
Those who can help remedy this situation are clinicians who have acquired this
knowledge and who can not only communicate with their colleagues using
appropriate terminology, but also present the information in a way best suited
to their colleagues.
This guide to meta-analysis is the work of a clinician and is aimed at dealing
with the difficulties mentioned above.
The reader is introduced to the main aspects of meta analysis using simple
terminology, but avoiding a simplistic approach.
There are examples of the most common errors made in its use.
The programme is designed for ease of use, which will help clinicians to
utilize meta-analysis.
The handbook contains a small chapter dedicated to the statistical procedures
which assumes that the reader has a knowledge of the basic points of
statistical methods, but could also prove interesting and informative to those
who are currently learning or who are consolidating their statistical
knowledge.
The author's choice to concentrate on a practical guide is justified as he has
dealt with this extensively, rather than concentrating on describing
statistical methods.
I am therefore very pleased to present this handbook of meta analysis, in the
certainty that it will be a success.
Prof. Giuseppe GALLUS
University of Milan - Italy
This handbook and accompanying program META, is divided into three parts: the
first deals with meta-analysis, the second illustrates some examples and the
third is the users manual.
The first part, even though it describes statistical methodology in detail, is
necessary for a good understanding of meta - analysis. It does not substitute
the classic texts on meta - analysis, but is intended to help users to
understand the main principles and to encourage them to become aquainte with
the subject and to guide them in the optimal use of the program.
The program contains very useful functions such as re-ordering and correction
of the archives, cumulative meta analysis, Number needed to Treat (NnT),
Publication Bias Assessment and graphics (eg. the Galbraith plot for the odds
ratio and risk difference and the cumulative Meta-Analysis).
The handbook allows the reader to integrate clinical and statistical methods
and can be used as a tool for teaching both practical and theoretical aspects
of meta analysis.
The reader should be able to carry out a formal meta analysis, report the
results and be able to interpret these correctly. Where a more detailed
evaluation is desired the reader is advised to look up the texts or articles
referred to in the bibliography.
The second part shows examples of meta analysis analysed both from the
meta-analytical stand point and also from the methodological view point,
illustrating the various functions described in the handbook.
PRESENTATION .............................................................................. | .......................................... | 7 |
PREFACE ........................................................................................... | .......................................... | 9 |
PART ONE ........................................................................................ | ......................................... | 11 |
INTRODUCTION ........................................................................... | ......................................... | 13 |
A BRIEF HISTORY ........................................................................ | ......................................... | 17 |
OBJECTIVES ................................................................................... | ......................................... | 19 |
PHASES OF A META-ANALYSIS TEST .................................. | ......................................... | 21 |
DIAS IN SEARCH IN META-ANALYSIS ................................. | ......................................... | 29 |
APPENDIX ...................................................................................... | ......................................... | 37 |
STATISTICAL PROCEDURES .................................................... | ......................................... | 39 |
Fixed effects models ..................................................................... | ......................................... | 40 |
Random effects models ............................................................... | ......................................... | 47 |
OPERETING PROCEDURES ......................................................... | ......................................... | 49 |
Control of data .............................................................................. | ......................................... | 49 |
Graphical rappresentation ........................................................... | ......................................... | 51 |
Numerical output .......................................................................... | ......................................... | 60 |
PART TWO ....................................................................................... | ......................................... | 69 |
5-ASA IN CROHN'S DISEASE ..................................................... | ......................................... | 71 |
OMEPRAZOLE VS. H-2 ANTAGONIST |
IN THE THERAPY OF GRASTRIC ULCER .............................. | .......................................... | 77 |
META-ANALYSIS IN LITERATURE: REFLECTION | ||
ON STATISTICAL HETEROGENITY ....................................... | .......................................... | 83 |
PROTON PUMP INHIBITORS (PPI) IN THE PREVENTIONS | ||
OF SEVERE ACUTE NSAID-RELATE STRIC DAMAGE IN | ||
HEALTY SUBJECTS ................................................................... | .......................................... | 87 |
HOW TO PRESENT A META-ANALYSIS .............................. | .......................................... | 89 |
REFERENCES .................................................................................. | .......................................... | 95 |
PART TREE ..................................................................................... | .......................................... | 97 |
CHAPTER 1 .................................................................................... | .......................................... | 99 |
GENERAL INFORMATION ........................................................ | .......................................... | 99 |
Minimum requirements .............................................................. | .......................................... | 99 |
Structure of the Program ............................................................ | ......................................... | 100 |
Principal Characteristics ............................................................ | ......................................... | 100 |
General user interfaces ............................................................... | ......................................... | 101 |
CHAPTER 2 .................................................................................... | ......................................... | 109 |
INSTALLATION .......................................................................... | ......................................... | 109 |
CHAPTER 3 .................................................................................... | ......................................... | 111 |
STARTING UP .............................................................................. | ......................................... | 111 |
CHAPTER 4 .................................................................................... | ......................................... | 115 |
PROCEDURES ............................................................................... | ......................................... | 115 |
Organization of studies in the tables ....................................... | ......................................... | 115 |
Statistical elaboration of studies .............................................. | ......................................... | 121 |
Display of the numerical result ................................................. | .......................................... | 127 |
Display of graph ......................................................................... | ......................................... | 128 |
CHAPTER 5 .................................................................................... | ......................................... | 133 |
RESTORING THE ARCHIVES .................................................... | ......................................... | 133 |
CHAPTER 6 .................................................................................... | ......................................... | 135 |
COPY/RESTORE ........................................................................... | ......................................... | 135 |
Copy from hard disk to floppy ................................................. | ......................................... | 136 |
Restore from floppy to hard disk ............................................. | ......................................... | 137 |
Formatting new disk ................................................................... | ......................................... | 137 |
Set up for the copy ..................................................................... | ......................................... | 137 |
Restore from automatic copy .................................................... | ......................................... | 139 |
CHAPTER 7 .................................................................................... | ......................................... | 141 |
SET UP THE VARIUS PARAMETERS ..................................... | ......................................... | 141 |
Setting up of tables of the studies ........................................... | ......................................... | 141 |
Set up of the output ................................................................... | ......................................... | 142 |
Setting up the paper directory .................................................. | ......................................... | 142 |
Setting up for the screen ........................................................... | ......................................... | 143 |
Time and date of the system ..................................................... | ......................................... | 147 |
Passwords to access the data .................................................. | ......................................... | 148 |
Setting up the printer ................................................................. | ......................................... | 149 |