Does Health Information Exchange Improve Patient Outcomes? A Longitudinal Study

The 2009 Health Information Technology for Economic and Clinical Health (HITECH) Act devoted $28 billion through its “meaningful use” incentive program to providers that adopted Electronic Health Records (EHRs) and participated in Health Information Exchange (HIE). Underlying these substantial investments is a belief that timely transfer of standardized electronic health information such as laboratory results and clinical summaries across the care continuum can facilitate coordinated patient care and improve health outcomes. Despite the recent growth of HIE and its potential benefits, only a few studies have examined the impact on quality of care in inpatient settings, and, to the best of our knowledge, no US-based studies have reported on HIE impacts on the tradeoff between readmission and a variety of quality measures.

We conducted a large scale retrospective study to examine the impact of HIE engagement on individual patients’ outcomes of Acute Myocardial Infarction (AMI) that is directly targeted by the Hospital Readmissions Reduction Program and a variety of other Centers for Medicare and Medicaid Services (CMS) programs, including the Hospital Value-Based Purchasing Program, and the Bundled Payments for Care Improvement (BPCI) Initiative. We linked the Florida State Inpatient Discharge (SID) data, which allows us to track a patient’s longitudinal visits across hospitals, with the American Hospital Association Annual and Information Technology Supplement surveys.

Using a difference-in-differences (DID) estimation approach, we compared changes in outcomes of a treatment group of targeted admissions before and after HIE engagement, relative to changes in outcomes of a control group that never participated in HIE. Our main outcome measures are the 30-day, 45-day, and 60-day all-cause readmission rates. To investigate whether the changes in readmission came at the cost of other quality measures, we also analyzed the impacts on length of stay, total charges, total number of procedures, discharges to a nursing facility or home health care, and in-hospital mortality. Our models adjust for patient characteristics and include hospital specific fixed effects to control for unobservable confounding factors. We employed placebo tests to rule out the concern that changes in outcome measures may have already started in time periods prior to the participation of HIE.

Overall, we found that HIE engagement did lower 30-day all-cause readmission rates for AMI patients. The decrease in readmissions after HIE engagement primarily came from reduced readmission to a different hospital. In addition, associated with the reduction in readmission were the rises in length of stay, number of procedures, and total charges, but there were no statistically significant changes in transfer, discharge destination or in-hospital mortality.

These results suggest that the decrease in readmission was achieved through the increased treatment intensity of inpatient care, but was not due to any strategic transfers or changes in discharge destination. HIE may have played an important role in determining the optimal cost tradeoff between inpatient care and readmission. A back-of-the-envelope calculation reveals that, for AMI condition alone, the HIE participation in Florida hospitals reduced 235 avoidable readmissions and saved $2,964,290 in cost annually.