Is the randomized controlled drug trial in Europe lagging behind the USA?
Authors: Heerspink Hiddo J. Lambers , Knol Mirjam J. , Tijssen Robert J. W. , Van Leeuwen Thed N. , Grobbee Diederick E. , De Zeeuw Dick 
Published: September 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT? • The USA, UK and Germany have a strong position in performance of drug and nondrug randomized controlled trials.• Europe's position in the quantitative and qualitative performance in drug randomized controlled trials in particular, and factors that drive the quantitative and qualitative performance of drug randomized controlled trials in Europe, are unknown. WHAT THIS STUDY ADDS • Europe's position in the quantitative and qualitative performance of randomized controlled drug trials lags behind USA.• Factors are identified that are associated with the difference in publication output between countries.• The number of headquarters of pharmaceutical companies in a country, the research expenditures by pharmaceutical companies, as well as health‐related R&D expenditures of a country appear to contribute to a relatively high scientific performance in randomized controlled drug trials.AIMSPerformance of randomized controlled drug trials (drugRCTs) adds to the scientific output, scientific knowledge, scientific training and up‐to‐date status of healthcare and may drive economy. The purpose of this study was to benchmark Europe's position on drugRCTs relative to the rest of the world, and to identify factors that may drive this performance.METHODSThe number of scientific publications on drugRCTs, indexed in PubMed and Thomson Scientific/Web of Science database over the period 1995–2004, was used as a proxy measure for the quantitative drugRCT output. The international citation impact of these publications was used as a proxy measure for the qualitative drugRCT output.RESULTSCountry's origin of 103 211 publications was determined. After adjustment for population size, the number of drugRCT publications from Europe, USA and Australia/Japan was 102, 124 and 44 publications per million inhabitants, respectively. The proportional increase in publication output from 1995 until 2004 was lower in Europe compared with the USA and Australia/Japan (29.1, 40.1 and 63.4%, respectively). The number of citations per publication was 4.9 in Europe, 7.0 in the USA and 3.4 in Australia/Japan. Within Europe, the UK, Germany and Italy produced most publications. Country‐specific factors associated with publication output in Europe were the number of pharmaceutical companies with headquarters in a country (R2 = 0.71, P < 0.001), national R&D expenditures by pharmaceutical companies (R2 = 0.63, P < 0.001) and health‐related R&D expenditures by national governments (R2 = 0.22, P = 0.052).CONCLUSIONSWhen adjusted for population size, quantitative and qualitative performance of drugRCTs in Europe lags behind the USA but is ahead of Australia/Japan. Several factors appear to explain the differences, among which are the number of headquarters of pharmaceutical companies in a country, the research expenditures by pharmaceutical companies, as well as health‐related R&D expenditures of a country. To enhance and strengthen Europe's position, researchers may strengthen their collaborations with local pharmaceutical companies, and national governments could increase their budgets for medical research funding.