Appendix Table 1.

Characteristics of study sample with depression: comparison of ACOs vs. control group

Beneficiary characteristics	Unadjusted pre-contract mean	Differences between ACOs and control group in pre-contract perioda			Differential change from pre-contract period to post-contract period, ACOs vs. control group
		Pioneer N=19,502 person-years	MSSP 2012 entry cohort N=38,062 person-years	MSSP 2013 entry cohort N=43,008 person-years	Pioneer		MSSP 2012 entry cohort	MSSP 2013 entry cohort
					Post Year 2012 N=7,577	Post Year 2013 N=7,963	Post Year 2013 N=16,112	Post Year 2013 N=14,246
Mean age, years	62.1	.2	1.1	.6	.4	.3	.1	.04
Female sex, %	70.7	2.3***	2.0***	1.5***	−.8	−.6	−1.3**	−.7
Race/Ethnicity, %
Non-Hispanic white	79.0	1.6	−1.1	.9	−.1	−.5	.1	.2
Non-Hispanic black	9.6	−.03	.4	−.5	.2	.2	−.2	−.3
Hispanic	8.5	−.4	.4	−.6	−.7*	−.2	.1	.1
Other	2.9	−1.2*	.2	.2	.6*	.5	0	.02
Medicaid recipient, %	51.1	−3.0*	.8	−3.8***	.7	0	−.2	−.5
Disabled, %b	59.4	−1.0	−2.6*	−2.0*	−.5	−1.5*	−.1	−.3
End-stage renal disease, %	1.4	.2*	.1	−.1*	−.1	−.2	.1	.1
Nursing home resident, %	6.3	−.5	3.3	−1.5***	−0	−.5	−.3	−.2
ZCTA-levelc characteristics, mean
Below FPL, %	10.4	−.5	−.4*	−.6**	.1	−.05	.05	.1
High school degree, %	73.3	2.1**	.7	1.4**	−.1	.2	−.1	−.1
College degree, %	18.3	2.3**	.6	1.3**	−.1	.1	−.1	−.1
CCW conditionsd
Total number, mean	6.1	0	.1	−.1	0	0	.1*	0
≥6 conditions, %	53.0	1.0	1.4	−.5	−.2	−.7	.6	0
≥9 conditions, %	25.2	0	1.4	−.7	.7	.1	.4	−.1
HCCe risk score, mean	1.7	0	0	0	0	0	0	−.01

^*p<.05

^**p<.01

^***p<.001

^aThe pre-contract period took place between 2009–2011 for the Pioneer and 2012 MSSP ACOs and between 2009–2012 for the 2013 MSSP ACOs.

^bIndicates that disability was the original reason for Medicare eligibility.

^cZip code tabulation area from the U.S. census data.

^dConditions assessed from the Chronic Condition Data Warehouse (CCW), including: 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, 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, glaucoma, and cataracts.

^eHierarchical Condition Category (HCC) score, which predicts annual spending based on diagnoses present in the prior year of claims and is used by Medicare for risk adjustment.