Implementation of HIE by an organization does not ensure utilization by individuals within the organization. Research has repeatedly demonstrated the organizational decision to adopt an innovation is frequently independent of individuals' adoption decisions.50
This exploratory study supports the point in the context of voluntary use HIE, but also suggests when and why such systems are actually used and how to improve implementation.
First, these results identify time constraints as a barrier to HIE usage. This simple finding, consistent with information-seeking theory and prior research, has immediate application to the design and function of HIE efforts. Healthcare is busy and fast-paced, and some physicians already believe HIE may not save time.52–54
Given that the voluntary access of an additional information source can be discouraged by time constraints, those wishing to implement HIE have two clear options. One avenue is to improve the utility of the information and the system; in effect, change the equation so the potentially available information is more valuable than the opportunity costs. Screen redesign, single sign-on, eliciting user needs, or improved record searching could all be means to that end. Alternatively, organizations can dramatically increase the level of functional integration between exchange partners' EHRs and their own. Case reports suggest tighter functional integration is associated with higher proportions of usage,12
and the problem of constrained time illustrates why. Directly placing the information made available by HIE into the organization's EHR may be politically, legally, organizationally, and even technically difficult, but it effectively removes from the user the decision to seek or not to seek information in such an alternative source.
However, these results provide an argument against addressing the problem of low usage by simply mandating usage. The decreased odds of usage for some encounters, but increased for others suggests users, have determined HIE is useful in some, but not all, instances. For current encounters that have little to do with previous utilization or information stored in other organizations, HIE may have less immediate value. Furthermore, the effect of comorbidities on novel usage, but not on basic usage, indicates users employ the system in a fashion to meet their immediate needs. For complex patients, the minimum information provided by the HIE system was probably not sufficient; those encounters required more detailed investigation. Mandating usage of an alternative information source that changes work processes needlessly, or when little potential value for the problem at hand exists, is a prescription for inciting resistance.55
Therefore, blanket mandatory usage of HIE systems may not solve perceived problems of underutilization.
Usage was much less likely for unfamiliar patients contradicting both expectations based on theory and conventional wisdom. An unknown patient is in effect the poster child for justifying HIE in the ED setting.56
Such a view is understandable, as repeated contact should increase provider knowledge about the patient's history and idiosyncrasies, thereby lessening the need to seek additional information. However, this unexpected relationship suggests one very practical reason why HIE, at least in the emergency setting, is actually used. In the ED, patient familiarity is undesirable, because it is indicative of patients with inappropriate sources of care. For the familiar patient, HIE might provide clinicians and organizations the necessary information to get and keep these patients out of the ED. The absence of an association between ED utilization at other locations and HIE usage reinforces this interpretation. Patient familiarity with a facility is more important than the frequency of a patient's visits to any ED.
Lastly, HIE usage appears to have non-clinical reasons as well. As noted, evidence suggests it is used in response to a facility's repeat patients, and the association between payer type and usage is also suggestive. While Medicaid does not boast the most generous reimbursement rates, some payment is better than no payment. Among patients for whom no payment could be expected, system usage was higher, suggesting the possibility of either using the system to locate past payers or to again help find patients more appropriate sources of care.
The primary limitation of this type of log file analysis is that we do not know if information-seeking efforts were successful. The files only record that a particular screen was viewed. We do not know if the user was able to locate the desired information on that screen or if it even existed. We simply know the user looked. Further studies with different designs would be necessary to investigate the success of search efforts.
Also, the results of this study have limited generalizability in terms of information system characteristics, the setting of care, and the population served. The HIE system considered in this study is a standalone system, separate from each organization's EHR. As the level of functional integration changes, the opportunities for users to access information from HIE systems also changes. In addition, the usage of separate information systems may require more substantial adjustments to work processes than are necessary to use systems with higher levels of integration. Other system or exchange effort characteristics such as technical architectures, user interfaces, and participating organizations may also limit generalizability. In addition, these ED-based finding may not be generalizable to the inpatient hospital setting, primary care encounters, or public health usage. Lastly, findings may not hold for HIEs serving broader payor groups as service needs and patterns of usage among the medically indigent in the ED may be substantially different from insured populations.
These results are limited in terms of scope, measurement, and causality. First, this study does not address any potential confounding due to user characteristics. While a necessary avenue of future inquiry, this study could not utilize measures of system users primarily because user activity is only recorded in the system for those encounters in which the system was accessed. Therefore, user characteristics could only be attributed to decisions to seek information, but not encounters where the system was not utilized. Second, the usage construct is limited because it does not include the specific information sought, particular search strategies, how usage fit into the patient encounter, or even if the search successfully yielded the desired information. Additionally, because our matching strategy was geared toward linking to patient encounters, we effectively excluded unsuccessful searches in our usages counts. Therefore, actual user interaction with the system was undoubtedly more frequent than our measure reported. Third, the strategy for linking user sessions to patient records was developed specifically for this study: it may not be applicable to other investigations. Furthermore, this method excluded usage by disease-management programs, social services, or public health. These constitute important applications not addressed in this investigation. Fourth, the cross-sectional design does not eliminate the potential bias from attrition. As noted, encounters covered by private insurance are not in the dataset. Therefore, this study may be undercounting previous utilization and previous diagnoses for some individuals. However, this limitation has no influence on the effect of a busy day at the ED (because that measure is patient-independent), injury (because it is unique to the encounter), or measures that are static across patients (ie, gender, race/ethnicity).