Changes in the use of hematopoietic stem cell transplantation: a model for diffusion of medical technology

Background
Innovations in hematology spread rapidly. Factors affecting the speed of introduction, international diffusion, and durability of use of innovations are, however, poorly understood.

Design and Methods
We used data on 251,106 hematopoietic stem cell transplants from 591 teams in 36 European countries to analyze the increase and decrease in such transplants for breast cancer and chronic myeloid leukemia and the replacement of bone marrow by peripheral blood as the source of stem cells as processes of diffusion. Regression analyses were used to measure the quantitative impact of defined macro- and microeconomic factors, to look for significant associations (t-test), and to describe the coefficient of determination or explanatory content (R2).

Results
Gross national income per capita, World Bank category, team density, team distribution, team size, team experience and, team innovator status were all significantly associated with some or all of the changes. The analyses revealed different patterns of associations and a wide range of explanatory content. Macro- and micro-economic factors were sufficient to explain the increase of allogeneic hematopoietic stem cell transplants in general (R2 = 78.41%) and for chronic myeloid leukemia in particular (R2 = 79.39%). They were insufficient to explain the changes in stem cell source (R2 =26.79% autologous hematopoietic stem cell transplants; R2 = 9.67% allogeneic hematopoietic stem cell transplants) or the decreases in hematopoietic stem cell transplants (R2 =10.22% breast cancer; R2=33.17% chronic myeloid leukemia).

Conclusions
The diffusion of hematopoietic stem cell transplants is more complex than previously thought. Availability of resources, evidence, external regulations and, expectations were identified as key determinants. These data might serve as a model for diffusion of medical technology in general.