Q: Is this considered a salami publication?
We are currently conducting a study that measures multiple variables. The paper A (focusing on pain) was already accepted by an international journal. Next, we would like to complete the paper B (focusing on QOL). The number of n and the number of cooperating facilities are increasing due to continuous measurement. The number of n and the research questions are different, so we assume this is not a salami publication. Is this understanding correct?
Journals discourage the submission of more than one article dealing with related aspects of the same study. If the study is designed around a single hypothesis and uses the same population and methods, its results must be presented in a single paper. However, from your question, it appears that both the research question and the dataset (the number of participants) are different in the two studies. Therefore, as you rightly assume, this is not a case of salami slicing.
A good practice in such a case, however, would be to openly declare that the findings of different aspects of a single study have been used to create separate papers and to cross reference or include a copy of the companion paper (if the first one has been published).
Hope this helps. All the best for your study!