Spreading a Medical Home Redesign: Effects on Emergency Department Use and Hospital Admissions

Robert J. Reid; Eric A. Johnson; Clarissa Hsu; Kelly Ehrlich; Katie Coleman; Claire Trescott; Michael Erikson; Tyler R. Ross; David T. Liss; DeAnn Cromp; Paul A. Fishman

doi:10.1370/afm.1476

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Figure 1
Use of in-person office visits, secure electronic message threads, and telephone encounters over time, 2008–2012.

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Table 1

Baseline Characteristics of the Study Populations, 2009

Characteristic	Group Health Practices (n=305,578)	Network Practices (n=107,365)	Total (N=412,943)
Age, mean (SD), y	43.5 (22.6)	40.4 (21.9)	42.7 (22.5)
Age-group, No. (%)
1–5 years	12,889 (4.2)	5,104 (4.9)	17,993 (4.4)
6–11 years	18,307 (5.9)	8,050 (7.7)	26,357 (6.4)
12–16 years	19,156 (6.2)	8,283 (7.9)	27,439 (6.6)
17–34 years	57,226 (18.5)	18,328 (17.5)	75,554 (18.3)
35–44 years	37,959 (12.3)	13,556 (13.0)	51,525 (12.5)
45–64 years	109,707 (35.6)	38,753 (37.1)	148,461 (36.0)
65–74 years	26,836 (8.7)	6,644 (6.4)	33,480 (8.1)
75–84 years	17,860 (5.8)	4,300 (4.1)	22,160 (5.4)
≥85 years	8,563 (2.8)	1,411 (1.4)	9,974 (2.4)
Education, neighborhood level, No. (%)
High	13,679 (40.1)	37,118 (35.5)	160,797 (39.0)
Medium	152,462 (49.4)	53,327 (51.1)	205,789 (49.8)
Low	32,331 (10.5)	13,985 (13.4)	46,316 (11.2)
Family income, neighborhood level, median (SD), $	59,882 (19,833)	51,909 (15,122)	57,787 (19,037)
Residence location, RUCA, No. (%)
Urban	269,515 (96.1)	75,241 (72.0)	371,756 (90.0)
Metropolitan/large rural	5,868 (1.9)	19,598 (18.8)	25,466 (6.2)
Small rural/isolated areas	2,811 (0.9)	7,472 (7.2)	10,283 (2.5)
Not mapped	3,309 (1.1)	2,129 (2.0)	5,438 (1.3)
Insurance segment, No. (%)
Medicare	55,435 (18.0)	13,038 (12.5)	68,473 (16.6)
Medicaid	9,196 (3.0)	838 (0.8)	10,034 (2.4)
Commercial/self-pay	221,190 (71.7)	86,904 (83.2)	308,064 (74.6)
Individual or family plan	22,682 (7.4)	3,660 (3.5)	26,342 (6.4)
Health plan product, No. (%)
HMO	257,466 (83.5)	73,383 (70.3)	330,849 (80.1)
PPO/POS	51,037 (16.5)	31,057 (29.7)	82,094 (19.9)
Insurance benefit design, No. (%)
Well-care waiver	203,166 (66.0)	65,949 (63.0)	269,115 (65.2)
High-deductible plan	3,157 (1.0)	997 (1.0)	4,154 (1.0)
Drug coverage	267,857 (87.0)	95,880 (92.0)	363,737 (88.1)
Morbidity, ACG RUB category, No. (%)
0 (nonusers)	37,417 (7.1)	11,134 (6.0)	48,551 (6.8)
1 (low morbidity)	36,332 (6.9)	12,414 (6.7)	48,746 (6.8)
2	53,530 (10.1)	19,901 (10.7)	73,431 (10.3)
3	133,188 (25.2)	45,905 (24.8)	179,093 (25.1)
4	31,992 (6.0)	10,613 (5.7)	42,535 (6.0)
5 (high morbidity)	14,142 (2.7)	4,026 (2.2)	18,168 (2.5)

HMO = health maintenance organization; POS = point of service; PPO = preferred provider organization; ACG = adjusted clinical group; RUB = Resource Utilization Band; RUCA = rural urban commuting area.

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Table 2

Adjusted Changes in Use for PCMH Patients Relative to Nonequivalent Control Patients

Measure of Use and Period	Change^a (95% CI)	P Value
Monthly primary care office visits per 1,000 enrollees
Implementation (year 1)
Q1	7.54 (6.22 to 8.85)	<.001
Q2	5.32 (3.84 to 6.80)	<.001
Q3	−1.18 (−2.87 to 0.51)	.17
Q4	−10.93 (−12.74 to −9.13)	<.001
Early stabilization (year 2)	−9.65 (−11.82 to −8.07)	<.001
Late stabilization (year 3)	−12.62 (−14.46 to −10.79)	<.001
Monthly ED visits per 1,000 enrollees
Implementation (year 1)
Q1	−0.02 (−0.38 to 0.35)	.93
Q2	−0.59 (−1.00 to −0.18)	.005
Q3	−0.86 (−1.33 to −0.38)	.000
Q4	−1.43 (−1.94 to −0.92)	<.001
Early stabilization (year 2)	−1.73 (−2.17 to −1.28)	<.001
Late stabilization (year 3)	−2.31 (−2.82 to −1.80)	<.001
Monthly inpatient admissions (total) per 1,000 enrollees
Implementation (year 1)
Q1	0.55 (0.30 to 0.80)	<.001
Q2	0.63 (0.36 to 0.91)	<.001
Q3	0.27 (−0.04 to 0.57)	.09
Q4	0.07 (−0.25 to 0.40)	.66
Early stabilization (year 2)	−0.01 (−0.28 to 0.25)	.93
Late stabilization (year 3)	0.05 (−0.25 to 0.35)	.74
Inpatient admissions (total; ACS conditions) per 1,000 enrollees
Implementation (year 1)
Q1	0.03 (−0.04 to 0.10)	.45
Q2	0.04 (−0.03 to 0.12)	.25
Q3	0.02 (−0.06 to 0.10)	.65
Q4	−0.04 (−0.12 to 0.05)	.38
Early stabilization (year 2)	−0.02 (−0.09 to 0.05)	.61
Late stabilization (year 3)	0.03 (−0.05 to 0.11)	.49

ED = emergency department; PCMH = patient-centered medical home; ACS = ambulatory care sensitive; ADG = adjusted diagnosis group.
↵a Estimated differences derived from regression models in the change in use for PCMH patients compared with nonequivalent control patients adjusted for age, sex, education, family income, residence location, insurance segment, health plan product, insurance benefit design, ADG mix, and calendar month.

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Supplemental Appendix. Contextual Factors at Group Health

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