Table 3.

Overview of Experimental and Quasi-experimental Studies and Their Findings

Study reference	Study design	Population type	Effect on outcome	Findings
Eftekhari et al.24 (2017)	Quasi-experimental: Instrumental Variable	Outpatient	Beneficial effect	HIE tenure was related to a significant reduction in the repetition of therapeutic medical procedures
				HIE tenure had no effect on the reduction of repetition of diagnostic medical procedures
Boockvar et al.32 (2017)	Randomized controlled trial as well as difference-in-difference	Inpatient	Beneficial effect	A significantly greater number of medication discrepancies were identified when HIE was used
				No effect was seen in the number of adverse drug events experienced when HIE was used
Murphy et al.37 (2017)	Randomized controlled trial	Emergency Department	Beneficial effect	Over a 12-month period costs HIE use resulted in $3200 savings related to ED use
Cunningham et al.35 (2017)	Quasi-experimental: Interrupted time series	HIV care	Beneficial effect	Use of Laboratory HIE was associated with higher odds of anti-retroviral therapy, viral suppression, and reduced racial disparities
Yaraghi30 (2015)	Quasi-experimental	Emergency Department	Beneficial effect	HIE usage was associated with a significant reduction in both laboratory tests as well as radiology examinations ordered per patient
Jung et al.27 (2015)	Quasi-experimental: Propensity score matching	Community	Beneficial effect	HIE usage was related to reduction in repeat imaging.
				Reduced repeat imaging was significantly related to annual savings of $32 460
Vest et al.17 (2015)	Quasi-experimental: Propensity score matching	Outpatient	Beneficial effect	HIE usage was related to reduction lower odds of readmission. This reduction was related to estimated savings of $605 000