ACO-Level Administrative Claims-Based Measure of Days at Home for Patients With Complex Chronic Conditions

Stakeholders have called for measures of how much time patients spend at home and in the community to incentivize coordinated, timely, and primary care-based services and reduce unnecessary acute care.

We developed a claims-based "Days at Home" Accountable Care Organization (ACO) measure for Medicare beneficiaries, intended to assess the number of days in a calendar year that adults with complex chronic disease spend at outside acute or postacute inpatient facilities.

Testing used 2017 and 2018 Medicare claims for fee-for-service patients enrolled in 610 Shared Savings Program ACOs. We used a split-half method for reliability testing, and a survey of technical experts and comparison to related measures for validity. The measure adjusts for 51 clinical and demographic variables and one social determinant of health (Medicaid dual-eligibility). To avoid unintended consequences of discouraging medically appropriate care and excessive reliance on nursing homes, the measure adjusts for mortality and new admissions to long-term nursing home care.

The cohort (N=1,154,779) was predominantly White (84.9%) and aged 65 years or older (84.0%), and 22.8% were Medicaid dual-eligible. Mean ACO-level adjusted days at home was 330.4, ranging from 291.0 to 345.9 days (interquartile range: 329.1-332.1). Split-sample reliability was 0.833. External experts rated the measure as having face validity; in assessing external validity the measure generally correlated with related measures.

The Days at Home ACO measure is a reliable and valid measure that can be used to promote coordinated and prevention-focused home-based and community-based care.