Table 1.
Characteristics of ACO Patients in Year before MSSP Entry and 2014, by MSSP Cohort
| MSSP 2012 cohort | MSSP 2013 cohort | MSSP 2014 cohort | ||||
|---|---|---|---|---|---|---|
| Patient characteristic | Pre-MSSP Year (2011) | 2014 | Pre-MSSP Year (2012) | 2014 | Pre-MSSP Year (2013) | 2014 |
| Mean age, y | 71.7 | 71.6 | 71.8 | 71.8 | 70.9 | 70.9 |
| Female sex, % | 58.4 | 57.6 | 57.3 | 56.7 | 57.9 | 57.6 |
| Race/ethnicity, % | ||||||
| White | 82.2 | 81.4 | 81.5 | 80.9 | 82.2 | 82.0 |
| Black | 8.2 | 8.3 | 8.1 | 8.2 | 9.3 | 9.1 |
| Hispanic | 5.1 | 5.3 | 6.2 | 6.2 | 5.1 | 5.1 |
| Other | 4.4 | 5.0 | 4.2 | 4.7 | 3.4 | 3.7 |
| Medicaid, full or partial dual1,% | 21.3 | 20.6 | 19.6 | 18.6 | 21.4 | 20.9 |
| Disabled,2 % | 23.2 | 23.7 | 22.4 | 22.2 | 25.8 | 25.6 |
| End-stage renal disease, % | 1.1 | 1.2 | 1.0 | 1.1 | 1.2 | 1.2 |
| Nursing-home resident, prior year, % | 1.7 | 1.4 | 1.4 | 1.3 | 1.6 | 1.6 |
| ZCTA-level characteristics, mean | ||||||
| % below FPL | 9.1 | 9.1 | 9.2 | 9.1 | 8.8 | 8.7 |
| % with high school degree | 75.7 | 75.8 | 75.6 | 75.7 | 76.0 | 76.1 |
| % with college degree | 19.2 | 19.2 | 18.7 | 18.9 | 19.1 | 19.2 |
| CCW conditions3 | ||||||
| Total no., mean | 5.81 | 5.94 | 5.90 | 5.97 | 5.87 | 5.87 |
| ≥6 conditions, % | 50.2 | 51.5 | 51.1 | 51.8 | 49.9 | 49.8 |
| ≥9 conditions, % | 20.9 | 22.7 | 21.5 | 22.5 | 22.2 | 22.4 |
| HCC risk score4, mean | 1.25 | 1.26 | 1.25 | 1.26 | 1.27 | 1.27 |
Abbreviations: Accountable care organization (ACO), Chronic Condition Warehouse (CCW), Hierarchical Condition Categories (HCC), Medicare Shared Savings Program (MSSP), ZIP Code tabulation area (ZCTA)
Means adjusted for the beneficiary’s HRR of residence and the ACO to which the beneficiary was attributed to hold constant over time the distribution of ACO-attributed beneficiaries across areas and ACOs.
Medicare and Medicaid dual eligibility defined as “full” or “partial” dual status using the “dual status” variable values 1-5, 6 and 8 as defined by CMS (https://www.resdac.org/cms-data/variables/Dual-Status-Code-occurs-12-times)
Indicates that disability was the original reason for Medicare eligibility
Chronic conditions from the Chronic Conditions Data Warehouse (CCW) included 27 conditions: acute myocardial infarction, Alzheimer’s disease, Alzheimer’s disease and related disorders or senile dementia, anemia, asthma, atrial fibrillation, benign prostatic hyperplasia, chronic kidney disease, chronic obstructive pulmonary disease, depression, diabetes, heart failure, hip/pelvic fracture, hyperlipidemia, hypertension, hypothyroidism, ischemic heart disease, osteoporosis, rheumatoid arthritis/osteoarthritis, stroke/transient ischemic attack, breast cancer, colorectal cancer, endometrial cancer, lung cancer, prostate cancer, cataracts, and glaucoma. Indicators for all 27 conditions were included in models. Counts of conditions included all conditions except cataracts and glaucoma.
Hierarchical Condition Categories (HCC) risk scores are derived from demographic and diagnostic data in Medicare enrollment and claims files, with higher scores indicating higher predicted spending in the subsequent year. For each beneficiary in each study year, we assessed the HCC score based on enrollment and claims data in the prior year.