Diagnostic Discordance, Health Information Exchange,
and Inter-Hospital Transfer Outcomes: a Population Study
Michael Usher, MD, PhD
, Nishant Sahni, MD
, Dana Herrigel, MD
, Gyorgy Simon, PhD
Genevieve B. Melton, MD, PhD
, Anne Joseph, MD, MPH
, and Andrew Olson, MD
Division of General Internal Medicine, Department of Medicine, University of Minnesota Medical School, Minneapolis, MN, USA;
Hospital Internal Medicine, Mayo Clinic Florida, Jacksonville, FL, USA;
Institute for Health Informatics, University of Minnesota Medical School,
Minneapolis, MN, USA;
Division of Colon and Rectal Surgery, Department of Surgery, University of Minnesota Medical School, Minneapolis, MN,
Division of General Internal Medicine, Department of Medicine, and Division of Pediatric Hospital Medicine, Department of Pediatrics,
University of Minnesota Medical School, Minneapolis, MN, USA.
BACKGROUND: Studying diagnostic error at the popula-
tion level requires an understanding of how diagnoses
change over time.
OBJECTIVE: To use inter-hospital transfers to examine
the frequency and impact of changes in diagnosis on pa-
tient risk, and whether health information exchange can
improve patient safety by enhancing diagnostic accuracy.
DESIGN: Diagnosis coding before and after hospital
transfer was merged with responses from the American
Hospital Association Annual Survey for a cohort of
patients transferred between hospitals to identify predic-
tors of mortality.
PARTICIPANTS: Patients (180,337) 18 years or older
transferred between 473 acute care hospitals from NY,
FL, IA, UT, and VT from 2011 to 2013.
MAIN MEASURES: We identified discordant Elixhauser
comorbidities before and after transfer to determine the
frequency and developed a weighted score of diagnostic
discordance to predict mortality. This was included in a
multivariate model with inpatient mortality as the depen-
dent variable. We investigated whether health information
exchange (HIE) functionality adoption as reported by hos-
pitals improved diagnostic discordance and inpatient
KEY RESULTS: Discordance in diagnoses occurred in
85.5% of all patients. Seventy-three percent of patients
gained a new diagnosis following transfer while 47% of
patients lost a diagnosis. Diagnostic discordance was as-
sociated with increased adjusted inpatient mortality (OR
1.11 95% CI 1.10–1.11, p < 0.001) and allowed for im-
proved mortality prediction. Bilateral hospital HIE partici-
pation was associated with reduced diagnostic discordance
index (3.69 vs. 1.87%, p < 0.001) and decreased inpatient
mortality (OR 0.88, 95% CI 0.89–0.99, p <0.001).
CONCLUSIONS: Diagnostic discordance commonly oc-
curred during inter-hospital transfers and was associated
with increased inpatient mortality. Health information
exchange adoption was associated with decreased discor-
dance and improved patient outcomes.
J Gen Intern Med
© Society of General Internal Medicine 2018
In today’s fragmented medical system, teamwork and inter-
professional communication have become increasingly funda-
mental for a safe, efficient diagnostic process.
many impediments to a patient receiving coordinated, high-
value care in this system; these barriers are most evident when
a patient is transferred between hospitals. Approximately 1.6
million patients are transferred between hospitals yearly. This
patient population is unique in its medical complexity and has
disproportionately high mortality.
Inter-hospital transfers are
complicated by incongruent information systems, indirect and
asynchronous communication, and geographical distance be-
tween institutions in a setting of high patient complexity and
This high-risk transition of care is a setting in which
breakdowns in the diagnostic process are likely to occur and
impact patient outcomes.
The impact of how diagnoses change with time and across
transitions of care is difficult to establish, particularly in large
This is despite a renewed focus on
diagnostic safety and efforts to minimize diagnostic error.
important reason for this is the lack of time varying informa-
tion in administrative datasets produced by hospitals. Studies
investigating unexpected care transitions, such as from a clinic
appointment to the hospital or readmission following dis-
charge from the ED have shown that changes in diagnoses
between each visit may help identify errors and provide feed-
back to improve care quality.
Inter-hospital transfers occur within a single day and pro-
vide data from two unique assessments. This creates an op-
portunity to capture documented changes with respect to di-
agnosis that may be associated with patient risk. In an optimal
setting where documentation is timely, accurate, and continu-
ally updated, there is little reason that documentation of diag-
noses, especially chronic conditions should differ across a
transfer except when a condition evolves, miscommunication
Electronic supplementary material The online version of this article
(https://doi.org/10.1007/s11606-018-4491-x) contains supplementary
material, which is available to authorized users.
Received June 27, 2017
Revised December 1, 2017
Accepted April 27, 2018