1) https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6020383/

2) https://journals.lww.com/md-journal/fulltext/2020/08210/association_of_patterns_of_multimorbidity_with.30.aspx

3) the attached PDF is the third article.

this is all related about comorbidity and length of stay in hospitals. (age / severity of illness / various health issues)

( 3 paragraphs each article)