Poster Board I-215
Human Development Index (HDI) is used by the United Nations to evaluate socio-economic status (SES) of countries all over the world. It is calculated based on 3 sub-indices: 1) Life Expectancy Index (LEI), reflecting general health status of a population; 2) Eduction Index (EI), assessing literacy and school enrollment, and 3) Gross Domestic Product Index (GDPI). Although most of the European countries are classified as well-developed with HDI >0.85, the differences between countries exist. The goal of this study was to evaluate whether HDI influences the rates of hematopoietic stem cell transplantation (HSCT) as well as transplantation outcome for adult patients with acute leukemia.
For the analysis of HSCT rates, all adult patients with acute leukemia (n=16403) treated with HSCT in 30 European countries, and registered in the EBMT database between 2001 - 2005 were included. Highly significant correlations were found for HDI and the number of HSCT per population for all types of transplants (R=0.78; p<0.0001), as well as separately for sibling-HSCT (R=0.84; p<0.0001), URD-HSCT (R=0.66; p<0.0001) and autoHSCT (R=0.43; p=0.02). When sub-indices were analyzed separately, the strongest correlations were found between the total HSCT rates and LEI (R=0.84; p<0.0001) as well as GDPI (0.77, p<0.0001), while correlation with EI was less pronounced (R=0.39; p=0.03).
Association of HDI and the outcome of HSCT was evaluated only for adults with acute myeloid leukemia treated with myeloablative, T-cell replete, allotransplantation (either sibling- or URD-HSCT), excluding cord blood transplants. Overall 2015 patients, aged 18-70 years (median 40) were included. Countries were classified according to HDI percentiles into 5 categories and the classes were tested for differences with regard to leukemia-free survival (LFS), relapse, and non-relapse mortality (NRM). The probabilities of LFS for the 5 consecutive classes with increasing HDI were as follows: 56%, 59%, 63%, 58%, and 68% (p=0.01). In a multivariate analysis transplants performed in countries belonging to the upper HDI category were associated with significantly higher LFS compared to the remaining ones (HR=1.36, p=0.008), which resulted mainly from reduced risk of relapse (HR=1.38, p=0.04) and to a lesser extent, reduced NRM (HR=1.32, p=0.1). In a univariate analysis, among HDI sub-indices, only the GDPI but not LEI and EI influenced outcome (p=0.01).
Results of our study indicate that the HDI, being a surrogate of the SES influences the rates of all types of HSCT in Europe. In case of patients with AML treated with allo-HSCT, the HDI influences outcome, however, the positive effect is seen only with regard to few countries with particularly high HDI, while the outcome in the remaining ones is comparable. As the effect on LFS depends mainly on differences in relapse incidence, it may result from either more intense induction-consolidation therapy, more intense conditioning regimen or better immunomodulation after alloHSCT in countries with the highest HDI. Further studies should focus on detailed aspects of the SES to clarify the background of our results.
Blaise:Gemzyme: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Pierre-Fabre: Consultancy, Research Funding.
Asterisk with author names denotes non-ASH members.