Acute Care Hospitalization Rate
The acute care hospitalization (ACH) rate is the percentage of home health stays during which the patient was admitted to an acute care hospital, historically measured over the first 60 days of home health. It is a claims-based, risk-adjusted measure that served for years as the industry's headline utilization metric before CMS began shifting to the Potentially Preventable Hospitalization measure.
How the measure works
ACH is calculated from Medicare fee-for-service claims: CMS links home health claims to inpatient hospital claims and counts stays with an acute admission in the measurement window, traditionally the first 60 days of the home health stay. Results are risk-adjusted for patient characteristics drawn from assessment and claims data, so agencies admitting sicker patients are compared against appropriately higher expected rates. Because the measure rides on claims, it captures every admission regardless of whether the agency knew about it.
The shift from ACH to PPH
CMS has been transitioning its programs from all-cause ACH toward the Home Health Within-Stay Potentially Preventable Hospitalization (PPH) measure, which counts only admissions and observation stays deemed potentially preventable and looks at the entire home health stay rather than the first 60 days. In the expanded Home Health Value-Based Purchasing model, ACH and the companion emergency department use measure were removed from scoring beginning with the CY2025 performance year in favor of PPH. The logic: an all-cause measure penalizes admissions no agency could prevent, while PPH targets the events home health can plausibly influence.
Why ACH still matters
Retirement from CMS scoring has not retired the concept. Hospitals, ACOs, and Medicare Advantage plans still evaluate post-acute partners on hospitalization rates, often using their own all-cause calculations from their own data. Internally, all-cause hospitalization remains the cleanest single indicator of clinical program effectiveness, and it is easier to track in real time than PPH, which requires knowing whether an admission was potentially preventable. Most well-run agencies track all-cause hospitalization weekly as the operational metric and treat PPH as the payment-facing translation of the same work.
How to reduce acute care hospitalizations
- Stratify hospitalization risk at start of care and front-load visits for the highest tier
- Reconcile medications at admission and after every hospital or ED contact
- Teach patients and caregivers specific red flags and who to call first
- Make on-call response fast enough that the agency, not the ED, is the path of least resistance
- Review every hospitalization within days to classify it as preventable or not, and feed the pattern into QAPI
Frequently asked questions
Is acute care hospitalization still used in HHVBP?
No. CMS removed the ACH and emergency department use measures from the expanded HHVBP model beginning with the CY2025 performance year, replacing them with the Potentially Preventable Hospitalization measure. Hospitalization performance still drives HHVBP scoring, just through the PPH lens.
Do observation stays count in the ACH rate?
The traditional ACH measure counted inpatient admissions, with emergency department and observation use captured separately. The newer PPH measure explicitly includes observation stays alongside inpatient admissions, closing a gap as hospitals shifted short stays to observation status.
What is a good hospitalization rate for a home health agency?
It depends on patient mix, which is why the official measures are risk-adjusted. Rather than chasing a universal number, compare your risk-adjusted result against state and national figures on Care Compare and track your own all-cause trend month over month.