Global myeloma research clusters, output, and citations: a bibliometric mapping and clustering analysis

PLoS One. 2015 Jan 28;10(1):e0116966. doi: 10.1371/journal.pone.0116966. eCollection 2015.


Background: International collaborative research is a mechanism for improving the development of disease-specific therapies and for improving health at the population level. However, limited data are available to assess the trends in research output related to orphan diseases.

Methods and findings: We used bibliometric mapping and clustering methods to illustrate the level of fragmentation in myeloma research and the development of collaborative efforts. Publication data from Thomson Reuters Web of Science were retrieved for 2005-2009 and followed until 2013. We created a database of multiple myeloma publications, and we analysed impact and co-authorship density to identify scientific collaborations, developments, and international key players over time. The global annual publication volume for studies on multiple myeloma increased from 1,144 in 2005 to 1,628 in 2009, which represents a 43% increase. This increase is high compared to the 24% and 14% increases observed for lymphoma and leukaemia. The major proportion (>90% of publications) was from the US and EU over the study period. The output and impact in terms of citations, identified several successful groups with a large number of intra-cluster collaborations in the US and EU. The US-based myeloma clusters clearly stand out as the most productive and highly cited, and the European Myeloma Network members exhibited a doubling of collaborative publications from 2005 to 2009, still increasing up to 2013.

Conclusion and perspective: Multiple myeloma research output has increased substantially in the past decade. The fragmented European myeloma research activities based on national or regional groups are progressing, but they require a broad range of targeted research investments to improve multiple myeloma health care.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bibliometrics*
  • Cluster Analysis
  • Humans
  • Multiple Myeloma*
  • Publications*
  • Reproducibility of Results
  • Research*
  • Time Factors

Grant support

This study was supported by research funds from the EU 6th FP to MSCNET (LSHC-CT-2006–037602, coordinator HEJ) (; from the Danish Cancer Society (; from the Danish Research Agency to CHEPRE (#2101–07–0007)(; from the KE Jensen Foundation (2006–2013) to HEJ and KD (; and from the Obelske Family Foundation to HEJ and MB (2006–2013) ( The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.