This is the website for 'The Health Care Compliance Association' but I could not find any more about the audit:
http://www.hcca-info.org/
I saw this but have not read the full text; it is 17 years old now and the author does not seem to be a ResearchGate member:
Dempsey, J. (2000). The appropriateness of admissions and the influences on a decision to admit. Journal of quality in clinical practice, 20(2‐3), 95-99.