Telemedicine - a scientometric and density equalizing analysis.
BACKGROUND
As a result of the various telemedicine projects in the past years a large number of studies were recently published in this field. However, a precise bibliometric analysis of telemedicine publications does not exist so far.


METHODS
The present study was conducted to establish a data base of the existing approaches. Density-equalizing algorithms were used and data was retrieved from the Thomson Reuters database Web of Science.


RESULTS
During the period from 1900 to 2006 a number of 3290 filed items were connected to telemedicine, with the first being published in 1964. The studies originate from 101 countries, with the USA, Great Britain and Canada being the most productive suppliers participating in 56.08 % of all published items. Analyzing the average citation per item for countries with more than 10 publications, Ireland ranked first (10.19/item), New Zealand ranked second (9.5/item) followed by Finland (9.04/item). The citation rate can be assumed as an indicator for research quality. The ten most productive journals include three journals with the main focus telemedicine and another five with the main focus "Information/Informatics". In all subject categories examined for published items related to telemedicine, "Health Care Sciences & Services" ranked first by far. More than 36 % of all publications are assigned to this category, followed by "Medical Informatics" with 9.72 % and "Medicine, General & Internal" with 8.84 % of all publications.


CONCLUSIONS
In summary it can be concluded that the data shows clearly a strong increase in research productivity. Using science citation analysis it can be assumed that there is a large rise in the interest in telemedicine studies.
Department of Health Economics, The Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
David A
DA
Groneberg
Institute of Occupational Medicine, Charité School of Medicine, Thielallee 73, 14195 Berlin, Germany.
Shaghayegh
S
Rahimian
Department of Health Economics, The Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Matthias
M
Bundschuh
Department of Health Economics, The Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Mario
M
Schwarzer
Department of Health Economics, The Institute of Occupational Medicine, Social Medicine and Environmental Medicine, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Alexander
A
Gerber
Health Economics, Department of Gynecology and Obstetrics, Goethe University Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.
Beatrix
B
Kloft
Bibliometry; Citation; Density equalizing map; Scientometry; Telemedicine