Limitations
The presented single-center study retrospectively analyzed patients from a clinical everyday population whose grouping was based solely on clinical assessment criteria. Thus, retrospective analysis looked for group-specific differences in collectives that were not fully comparable, which could result in a distorted picture. In addition, the fundamentally limited informative value of retrospective data analyses and observational studies should be pointed out, and last but not least, the small and unequal case numbers of the subgroups could cause a bias.