LACE Index — Readmission Risk Calculator
The LACE Index predicts the risk of unplanned 30-day hospital readmission or death. It combines Length of stay, Acuity of admission, Comorbidity (Charlson), and Emergency department visits in the prior 6 months into a single validated risk score.
About
The LACE Index was developed by Dr. Carl van Walraven and colleagues in 2010 and published in the Canadian Medical Association Journal (CMAJ). It was derived from a cohort of 4,812 medical and surgical patients discharged from 11 teaching and community hospitals in Ontario, Canada. The score uses four components: L — Length of stay (categorized into 6 levels from 1 to ≥14 days, with weighted points 1-7), A — Acuity of the admission (3 points if admitted through the ED or as an urgent case, 0 otherwise), C — Comorbidity as measured by the Charlson Comorbidity Index (converted to a 0-5 point scale), and E — Emergency department visits in the 6 months prior to admission (0-4 visits, weighted 0-4 points). The total score ranges from 0 to 19. The LACE Index has been externally validated in multiple healthcare systems and demonstrates reasonable discriminative ability for 30-day readmission (c-statistic 0.68-0.78). It is widely used in hospital quality improvement programs, transition of care initiatives, and as a case-mix adjustment tool for readmission benchmarking.
Formula
LACE = L(LOS) + A(Acuity) + C(Charlson) + E(ED visits past 6 months)
LOS: 1 day=1, 2=2, 3=3, 4-6=4, 7-13=5, ≥14=7. Acuity: 3 if admitted from ED or urgent, else 0. Charlson: 0=0, 1=1, 2=2, 3=3, ≥4=5. ED visits (past 6 months): 0=0, 1=1, 2=2, 3=3, ≥4=4.
Score Interpretation
Hospital readmissions are a major quality metric and cost driver in healthcare systems worldwide. The LACE Index is one of the most widely validated readmission prediction tools and is used by hospitals for risk stratification, resource allocation for transitional care programs, and as a risk-adjustment variable in readmission benchmarking. The index has been embedded in electronic health records and discharge planning workflows across Canada, the United States, and Europe. Studies have shown that LACE-guided transitional care interventions can reduce 30-day readmission rates by 15-30% in high-risk populations.
Low Readmission Risk — 0–4
Low probability of 30-day unplanned readmission.
Management: Routine discharge planning; low readmission probability.
Moderate Readmission Risk — 5–9
Moderate probability of 30-day unplanned readmission.
Management: Early follow-up within 7-14 days. Medication reconciliation and patient education recommended.
High Readmission Risk — 10–19
High probability of 30-day unplanned readmission.
Management: Intensive discharge planning and transitional care. Follow-up within 7 days. Home health referral and telehealth monitoring.
Reference Ranges
| Population | Normal Range |
|---|---|
| General medical/surgical inpatients | 0 (low risk) to 19 (high risk) |
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View medical review board & editorial policy →Example Calculation
A 65-year-old man with diabetes (CCI=2), admitted from the ED for cellulitis, LOS 8 days, with 2 ED visits in the prior 6 months. L=5 (LOS 7-13), A=3 (ED admission), C=2 (CCI=2), E=2 (2 visits). Total LACE = 5+3+2+2 = 12/19 (high risk). Recommended: intensive transitional care with 7-day follow-up.
Related Conditions
Common Mistakes
Counting planned ED visits (e.g., scheduled IV therapy) in the ED visits component
Only count unplanned ED visits in the 6 months prior to admission. Scheduled or planned visits should not be included.
Using total hospital days including days in the ED observation unit
LOS should only include days after admission to an inpatient bed. Observation unit or ED holding time should not be counted.
Frequently Asked Questions
Can the LACE Index be used for all types of patients?
What is a high-risk LACE score cutoff?
References
- van Walraven C, Dhalla IA, Bell C, et al. Derivation and validation of an index to predict early death or unplanned readmission after discharge from hospital to the community. CMAJ. 2010;182(6):551-557. PubMed
- Grunier A, Dhalla IA, van Walraven C, et al. Validation of the LACE Index to predict early death or unplanned readmission after discharge. J Hosp Med. 2011;6(8):444-450.