Web Appendix 1.

Characteristics of Beneficiaries Included and Excluded from the Study.

	Four or More Visits in 2011 (Included)	Fewer than Four Visits in 2011 (Excluded)
N (%)	3,200,158 (69.5)	1,405,475 (30.5)
Female, %	58.7	56.8
Age, mean yrs.	76.8	75.4
Race/ethnicity, %
Non-Hispanic white	84.8	82.8
Black	6.7	7.6
Hispanic	4.6	5.0
Asian	2.5	2.5
Other	1.2	2.1
Medicaid dual eligible, %	15.5	18.2
Original coverage from disability, %	8.8	7.0
HCC score, median (IQR)	1.3 (1.0-1.8)	1.1 (0.9-1.3)
Visit patterns 2011-13, median (IQR)
COC score	0.258 (0.17-0.42)	0.333 (0.19-0.78)
UPC score	0.467 (0.33-0.63)	0.667 (0.50-1.0)
Total visits	14 (8-21)	4 (2-7)
Total physicians	13 (8-21)	4 (1-6)
ED episode 2011-13, %	59.8	46.9
Emergency visit	32.8	26.5
Observation stay	7.8	5.0
Admission through the ED	19.2	15.3

NOTE: Continuously enrolled Medicare fee-for-service beneficiaries were at least 66 years of age and had 4 or more or fewer than 4 ambulatory evaluation and management visits in 2011 and were followed up to 24 months until death or first emergency department (ED) episode, if one occurred. An emergency department (ED) episode is an ED visit and discharge, observation stay through the ED, or admission through the ED. Visit patterns and ED episodes from 2011-13 were not calculated over the same number of months for all beneficiaries. Hierarchical Condition Category (HCC) score was calculated from utilization in 2010. IQR is interquartile range.