The Impact of Community Health Information Exchange Usage on Time to Reutilization of Hospital Services

Chantel Sloan-Aagard; Jeffrey Glenn; Juan Nañez; Scott B. Crawford; J. C. Currey; Emily Hartmann

doi:10.1370/afm.2903

Article Figures & Data

Figures

Tables
Additional Files

Download figure
Open in new tab
Download powerpoint
Figure 1.
Flowchart of cohort and group selection.
ED = emergency department; ICD-10 = International Statistical Classification of Diseases, 10th Revision; PCP = primary care physician; PHIX = Paso del Norte Health Information Exchange.
^a These codes were excluded because they indicate normal pregnancy or elective termination of pregnancy. For example, patients with false labor were labeled as inpatient in the system. They were expected to return as inpatient for delivery, and thus were excluded.
^b Patients brought to the hospital through the prison system, border control, or other law enforcement agencies could not be reliably followed-up. Also, patients with military insurance are referred out from military hospitals for specific purposes, making them non-representative of the larger population.
Download figure
Open in new tab
Download powerpoint
Download figure
Open in new tab
Download powerpoint
Figure 2.
Survival curves for key characteristics by case group (ED or inpatient visit).
ED = emergency department; F = female; HIE = health information exchange; INP = inpatient; = male; NonHisp = Non-Hispanic; PHIX = Paso del Norte Health Information Exchange.
Note: Censoring events are shown as crosses and CIs are included except for insurance categories, for ease of viewing. Time (x axis) is in days. Median number of days to second hospital visit for each group are shown in the upper right corner of the plot. If the number of persons re-entering the ED or INP never drops below 50%, the median cannot be calculated.
Download figure
Open in new tab
Download powerpoint
Figure 3.
Proportion of ICD-10 code groups reported during hospital visits and physician use of HIE.
ED = emergency department; HIE = health information exchange; ICD-10 = International Statistical Classification of Diseases, 10th Revision.
Note: Graphic represents the proportion of ICD-10 code groups reported during hospital visits, divided by the first inpatient visit and the second visit (ED or inpatient combined, cases only), and whether the HIE was accessed between the first and second visit by a primary care physician. A similar chart for all variables in the model is included in Supplemental Figure 3.

View popup

Table 1.

Cohort Characteristics by HIE Lookup at Post-Discharge Appointment (N = 8,216)

Characteristic	HIE Lookup (n = 270)	No HIE Lookup (n = 7,946)	P Value
Gender, No. (%)			.09
Female	151 (56)	4,860 (61)
Male	119 (44)	3,085 (39)
NA	0 (0)	1 (0)
Age, y, No. (%)			.60
18-49	115 (43)	3,245 (41)
≥50	155 (57)	4,701 (59)
Ethnicity, No. (%)			<.001^{^a}
Hispanic	153 (57)	5,611 (71)
Non-Hispanic	54 (20)	1,083 (14)
NA	63 (23)	1,252 (16)
Insurance status, No. (%)			.57
Medicaid	33 (12)	1,049 (13)
Medicare	63 (23)	1,929 (24)
Private	75 (28)	2,368 (30)
Self-pay	52 (19)	1,236 (16)
Uninsured	24 (9)	705 (9)
NA	23 (9)	659 (8)
Patient days, median, (IQR)	108 (11-256)	66 (11-169)	<.001^{^a}

HIE = health information exchange; IQR = interquartile range; NA = not available.
↵a Significance level 0.001

View popup

Table 2.

Cohort Characteristics by Outcome Group (N = 8,216)

Characteristic	Case Group 1: ED Visit (n = 3,809)	Case Group 2: Inpatient Visit (n = 2,627)	Controls: No Second Hospital Visit (n = 1,780)	P Value
Gender, No. (%)				<.001^{^b}
Female	2,441 (64)	1,661 (63)	909 (51)
Male	1,367 (36)	966 (37)	871 (49)
NA	1 (0)	0 (0)	0 (0)
Age, y, No. (%)				<.001^{^b}
18-49	1,411 (37)	1,111 (42)	838 (47)
≥50	2,398 (63)	1,516 (58)	942 (53)
NA	0 (0)	0 (0)	0 (0)
Ethnicity, No. (%)				.003^{^a}
Hispanic	2,498 (66)	2,005 (76)	1,261 (71)
Non-Hispanic	465 (12)	370 (14)	302 (17)
NA	846 (22)	252 (10)	217 (12)
Insurance status, No. (%)				<.001^{^b}
Medicaid	509 (13)	368 (14)	205 (12)
Medicare	1,038 (27)	616 (23)	338 (19)
Private	1,095 (29)	831 (32)	517 (29)
Self-pay	484 (13)	293 (11)	511 (29)
Uninsured	323 (8)	302 (11)	104 (6)
NA	360 (9)	217 (8)	105 (6)
HIE accessed, No. (%)				<.001^{^b}
Yes	107 (3)	60 (2)	103 (6)
No	3,702 (97)	2,567 (98)	1,677 (94)
Patient days, median (IQR)	43 (10-108)	26 (2-88)	290 (207-343)	<.001^{^b}

ED = emergency department; HIE = health information exchange; IQR = interquartile range; NA = not available.
Note: Outcome groups were based on whether a patient visited an ED or was rehospitalized (inpatient visit) for the same or similar symptoms as indicated by the ICD-10 codes from first hospital discharge.
↵a Significance level 0.01
↵b Significance level 0.001

View popup

Table 3.

Cox Proportional Hazards Results by Case Group

Characteristic	Case Group 1: ED Visit (n = 3,809)			Case Group 2: Inpatient Visit (n = 2,627)
Characteristic	Coefficient	HR (LCI, UCI)	P Value	Coefficient	HR (LCI, UCI)	P Value
Gender
Female	Reference	Reference	Reference	Reference	Reference	Reference
Male	−0.26	0.77 (0.71, 0.84)	<.001^{^c}	−0.28	0.75 (0.69, 0.82)	<.001^{^c}
Age, y
18-49	Reference	Reference	Reference	Reference	Reference	Reference
≥50	0.17	1.18 (1.08, 1.3)	<.001^{^c}	0.13	1.13 (1.02, 1.26)	.02^{^a}
Ethnicity
Hispanic	Reference	Reference	Reference	Reference	Reference	Reference
Non-Hispanic	−0.20	0.82 (0.73, 0.91)	<.001^{^c}	−0.17	0.84 (0.75, 0.95)	.004^{^b}
Insurance type
Medicaid	Reference	Reference	Reference	Reference	Reference	Reference
Medicare	−0.13	0.88 (0.76, 1.02)	.08	−0.10	0.91 (0.77, 1.07)	.24
Private	−0.22	0.81 (0.71, 0.91)	<.001^{^c}	−0.17	0.84 (0.74, 0.96)	.01^{^a}
Self-pay	−0.71	0.49 (0.43, 0.57)	<.001^{^c}	−0.94	0.39 (0.33, 0.46)	<.001^{^c}
Uninsured	0.00	1 (0.85, 1.17)	1.00	0.04	1.04 (0.88, 1.23)	.65
HIE accessed
No	Reference	Reference	Reference	Reference	Reference	Reference
Yes	−0.53	0.59 (0.46, 0.76)	<.001^{^c}	−0.59	0.56 (0.42, 0.74)	<.001^{^c}

ED = emergency department; HIE = health information exchange; HR = hazard ratio; LCI = lower confidence interval; UCI = upper confidence interval.
Note: The dependent variables are being rehospitalized (inpatient visit) or having an ED visit after the post-inpatient primary care physician visit. Independent variables are whether the HIE was accessed, insurance category, age, ethnicity, and gender.
↵a Significance level 0.05
↵b Significance level 0.01
↵c Significance level 0.001