In patients with myelodysplastic syndromes with del(5q), factors other than age and sex contribute to the prognostic advantage, which diminishes over time.

This study aimed to determine the extent to which the prognostic advantage of myelodysplastic syndromes (MDS) with del(5q) is due to the more favourable age and sex distribution of patients in that group when compared to other MDS subtypes. A total of 1912 MDS patients from the Duesseldorf registry with less than 5% blasts in the bone marrow were evaluable and had complete covariates. As endpoints, overall survival and progression to acute myeloid leukaemia (AML) were considered. Cox models were computed for both outcomes. A multivariate Cox model for survival confirmed higher age and male sex as risk factors. In addition, we found a survival advantage of 9·1 years for MDS del(5q) patients compared to refractory cytopenia with unilineage dysplasia, while the survival advantage of MDS del(5q) over refractory cytopenia with multilineage dysplasia was 18·6 years. Considering progression to AML, we did not find any significant differences between the World Health Organization classification subtypes. Our analyses show that the higher survival probabilities of MDS del(5q) patients are not only due to age and sex, although higher age and male sex were also important risk factors. Interestingly, it seems that the survival advantage of MDS del(5q) decreases over time.