Time changes in predictive power of established and recently proposed clinical, cytogenetical and comorbidity scores for Myelodysplastic Syndromes.

Recent improvements in the treatment of Myelodysplastic Syndromes have fostered further interest in the development of prognostic scores. Prognostic indices such as the IPSS were developed and later validated assuming their predictive values to be unchanged over time. A systematic analysis of the possible variability of predictive power over time in different scores is still lacking and was the aim of this study.For 243 primary MDS patients from a single institution treated with supportive care, 19 established or modified scoring systems based on different prognostic factors (clinical, cytogenetical and/or comorbidity) were analysed for their variability over time by statistical methods that quantify time variations in the risk relations (specifically the risk ratios of Cox models) between prognostic subgroups.Established scores based mainly on clinical parameters showed strong to moderate loss of predictive power over time whereas cytogenetic scores maintained their predictive power. Scores including comorbidity data showed gain of predictive power over time.The development and comparison of prognostic systems have to take into account their stability versus the possibility or need for re-evaluation. Possibly not only re-evaluation after time is of importance, but also different weighting of items constituting scores.