Study limitations
As this is a post hoc analysis, results should be used only for hypothesis generation. In addition to the small number of patients in some defined subgroups, larger prospective studies are warranted to confirm the findings. Laboratory values were partly assessed in different local and central laboratories and any slight variability in values was not considered. Reference ranges were not compared individually to those provided by the different laboratories, however values from the different labs were compared to more general reference ranges described in the literature [