Download U.S. Hospital Use of Echocardiography

JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY
VOL. 67, NO. 5, 2016
ª 2016 BY THE AMERICAN COLLEGE OF CARDIOLOGY FOUNDATION
ISSN 0735-1097/$36.00
PUBLISHED BY ELSEVIER
http://dx.doi.org/10.1016/j.jacc.2015.10.090
U.S. Hospital Use of Echocardiography
Insights From the Nationwide Inpatient Sample
Alexander Papolos, MD, Jagat Narula, MD, PHD, Chirag Bavishi, MD, MPH, Farooq A. Chaudhry, MD,
Partho P. Sengupta, MD, DM
ABSTRACT
BACKGROUND Increased use of echocardiography (echo) raises questions of whether echo is an overused diagnostic
procedure in the United States.
OBJECTIVES This study investigated national trends, practice patterns, and patient outcomes associated with inpatient
echo use reported in the Nationwide Inpatient Sample (NIS).
METHODS We identified admission diagnoses most commonly associated with echo use and performed multivariate
logistic regression within each diagnosis cohort to assess whether echo use was associated with all-cause inpatient
mortality. Secondary analysis was performed within our institution to validate use trends identified in the NIS database.
RESULTS Between 2001 and 2011, the absolute volume and incidence of echo steadily increased at average annual rates
of 3.41% and 3.04%, respectively. In 2010, the use of echo was associated with lower odds of inpatient mortality among
hospitalizations for acute myocardial infarction (adjusted odds ratio [OR]: 0.74; 95% confidence interval [CI]: 0.63 to
0.86; p < 0.001), cardiac dysrhythmia (adjusted OR: 0.72; 95% CI: 0.55 to 0.94; p ¼ 0.02), acute cerebrovascular
disease (adjusted OR: 0.36; 95% CI: 0.31 to 0.42; p < 0.001), congestive heart failure (adjusted OR: 0.82; 95% CI: 0.72
to 0.94; p ¼ 0.005), and sepsis (adjusted OR: 0.77; 95% CI: 0.70 to 0.85; p < 0.001). In 2010, these 5 diagnoses
accounted for 3.7 million hospital admissions (9% of all hospitalizations); however, echo was reported in only 8% of
cases. Secondary analysis of imaging practices at our institution confirmed underuse of echo among patients who died
during hospitalization for indications identified in the NIS database.
CONCLUSIONS Despite increasing rates of performance, echo may be underused during critical cardiovascular
hospitalizations. (J Am Coll Cardiol 2016;67:502–11) © 2016 by the American College of Cardiology Foundation.
E
chocardiography (echo) is the most ubiqui-
showed that the use of echo (transthoracic echocardi-
tous, versatile, and cost-effective cardiac
ography [TTE] and transesophageal echocardiogra-
imaging
These
phy [TEE]) increased by 7.7% per year from 1999 to
attributes, in combination with an infinitesimal risk-
2004 (5), and it nearly doubled from 1999 to 2008
to-benefit ratio, explain why echo has become a
(6). Reports from the Veterans Healthcare Adminis-
mainstay of the cardiovascular evaluation. Wide-
tration also demonstrated an annual increase in total
spread reliance on echo has fostered growing concern
echo volume of 3.9% from 2000 to 2007, but this
for its overuse and has led to the formation of appro-
finding was primarily driven by population expansion
priate use criteria (1). Although several studies have
rather than by a change in imaging practices (7).
demonstrated adherence to these guidelines in
Given the paucity of data, this study was conducted
clinical practice (2–4), national trends in the use of
to describe trends, practice patterns, and patient
echo have not been fully described. The closest ap-
outcomes associated with the use of echo through
proximations are from Medicare literature, which
a comprehensive assessment of hospitalizations
modality
available
(1–5).
Listen to this manuscript’s
audio summary by
JACC Editor-in-Chief
Dr. Valentin Fuster.
From the Mount Sinai Medical Center, New York, New York. Dr. Narula has received research grants to the institution from Philips
Healthcare and GE Healthcare in the form of equipment. Dr. Sengupta is an advisor to Saffron Technology Hearts Labs; and is a
consultant to Edwards Lifesciences. All other authors have reported that they have no relationships relevant to the contents of
this paper to disclose. Brian Griffin, MD, served as Guest Editor for this paper.
Manuscript received August 28, 2015; revised manuscript received October 7, 2015, accepted October 8, 2015.
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
503
Echocardiography Use in U.S. Hospitals
available in the Nationwide Inpatient Sample (NIS)
artery disease (CAD), sepsis, valvular disease,
ABBREVIATIONS
database (8).
and nonspecific chest pain (CCS diagnoses
AND ACRONYMS
codes: 2, 96, 100, 102, 101, 106, 108, and 109).
METHODS
We subsequently applied 3 criteria to the
We first queried the NIS to quantify temporal trends
in inpatient echo use between 2001 and 2011. Next we
explored the 2010 database to investigate whether
echo use was associated with all-cause in-hospital
mortality among the diagnoses for which echo is most
commonly performed.
sample: 1) non–emergency department ad-
AMI = acute myocardial
infarction
APR-DRG = All Patient
missions were excluded to control for con-
Refined–Diagnosis Related
founding hospital-to-hospital transfers; 2)
Group Severity Score
hospitalizations lasting <24 h were excluded
CAD = coronary artery disease
to counter bias created by critically ill patients
CCS = Clinical Classification
in whom a fatal outcome occurred without
Software
sufficient lead time to obtain an echo exami-
CHF = congestive heart failure
DATA SOURCE. The NIS is the largest, publicly
nation if clinically indicated; and 3) neonatal
echo = echocardiography
available, all-payer inpatient database in the United
patients were excluded. The final sample
ICD-9-CM = International
included an estimated 3,651,503 hospitaliza-
Classification of Disease-9th
States
(8).
Annually,
the
NIS
is
composed
of
discharge-level data from roughly 8 million hospi-
tions and contained 31% of all estimated
talizations and approximates a stratified sample of
inpatient echo examinations performed in
20% of community hospitals in the United States. The
2010. State-specific rates of inpatient echo use
sampling methodology of the NIS permits the appli-
were derived by dividing estimated statewide
cation of weighting variables that allow for the
echo volume by the corresponding volume of
calculation of national estimates, which have been
estimated hospitalizations, as recorded in the
validated against other U.S. hospital registries (9).
2010 NIS.
edition-Clinical Modification
NIS = Nationwide Inpatient
Sample
OR = odds ratio
TEE = transesophageal
echocardiography
TTE = transthoracic
echocardiography
Each hospitalization within the database contains
Patients’
PATIENT-RELATED AND HOSPITAL CHARACTERISTICS.
diagnoses are documented in parallel, as both Inter-
To assess for association between echo performance
national Classification of Disease-9th edition-Clinical
and diagnosis-specific hospital mortality rates, we
clinical
and
resource-use
information.
Modification (ICD-9-CM) and clinically meaningful
stratified the sample by primary CCS diagnosis code
clusters of ICD-9-CM’s, termed Clinical Classification
(admission diagnosis). Available independent vari-
Software (CCS) codes.
ables for analyses included the patient’s age, race,
sex, insurance status, number of comorbidities,
SEE PAGE 512
median household income by zip code, illness
severity score, and admission day (weekend vs.
TEMPORAL TRENDS IN ECHO USE. The Healthcare
weekday). Information on race was categorized as
Cost and Utilization Project online NIS registry
white, black, Hispanic, and other (Asian, Pacific
(HCUPnet) (10) was queried by the ICD-9-CM for echo
Islander, Native American, and unknown). Insurance
(procedure code 88.72). This provided national esti-
status was classified based on the expected primary
mates of hospitalizations in which echo was per-
payer and included Medicare, Medicaid, private in-
formed from 2001 through 2011. The ICD-9-CM 88.72
surance, and other insurance types, including pa-
is used for coding of all forms of echo. Therefore the
tients who were uninsured. The number of comorbid
database cannot differentiate admissions in which
conditions was a sum of all listed diagnoses. Median
TTE examinations or other forms of echo such as TEE
household
were performed. However, this limitation is likely to
divided into income quartiles defined as follows:
be insignificant given that the approximate ratio of
1) $1 to $40,999; 2) $41,000 to $50,999; 3) $51,000
TTE use to TEE use is close to 100:1 (6), as well as the
income
per
patient’s
zip
code
was
to 66,999; and 4) $$67,000. Illness severity was
clinical insight that few patients receive TEE without
based on All Patient Refined–Diagnosis Related
first undergoing TTE.
Group (APR-DRG) severity score, a validated clini-
STUDY POPULATION. The 2010 NIS was used to eval-
uate for an association between echo use and diagnosis
specific all-cause hospital mortality. The dataset was
first confined to admission diagnoses associated with
the greatest proportion of echo use (representing
one-half of all estimated inpatient echo studies in
cally coherent set of illness severity and risk of
mortality subclasses that adjust for the interactions
between a patient’s primary diagnosis, comorbidities, age, and procedures occurring during hospitalization, defined as: 1) minor; 2) moderate; 3) major;
and 4) extreme (11).
2010) (10). This included acute myocardial infarction
HOSPITALIZATION
(AMI), cardiac dysrhythmia, acute cerebrovascular
point was in-hospital mortality and was analyzed
OUTCOME. The
disease, congestive heart failure (CHF), coronary
using multivariate regression, as described later.
primary end-
504
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
STATISTICAL ANALYSIS. Temporal trends in the
distribution of the NIS study sample. We attempted to
incidence of national echo use per hospitalization
correct for this disparity and more closely emulate the
between 2001 and 2011 were obtained by dividing the
NIS study sample by including only patients who
estimated annual volume of studies performed by the
were $60 years of age. We then performed both
estimated total number of annual hospitalizations.
univariate analysis and multivariate logistic regres-
Use growth (absolute and per hospitalization) was
sion adjusting for patients’ sex, race, insurance type,
analyzed by calculating the average annual percent-
number of chronic diseases, administration of diag-
age change from 2001 to 2011.
nostic cardiac catheterization or cardiac stress test,
The 2010 sample was dichotomized into hospitali-
admission day, and APR-DRG severity index among
zations in which echo was or was not performed, and
each admission-diagnosis cohort to assess for an as-
descriptive statistics were generated on frequencies
sociation between echo performance and hospital
and proportions for categorical variables (age, sex,
mortality rates.
race, insurance, income quartile by zip code, number
Results were reported as adjusted odds ratios (ORs)
of chronic diseases, administration of diagnostic car-
with 95% confidence intervals (CIs). All statistical
diac catheterization, administration of cardiac stress
analyses incorporated primary sampling units and
test [exercise and pharmacologic], admission day,
clusters to obtain national estimates and were per-
and APR-DRG severity score). Means with standard
formed using Statistical Analysis Software (SAS, Cary,
error were reported for continuously coded variables
North Carolina) version 9.3 with a 2-sided significance
(age and number of chronic diseases). Student t tests
level set at p < 0.05.
and the chi-square tests were used to evaluate
This study was considered to be exempt research
demographic features among groups. To assess
with respect to the requirement for informed con-
for an association between echo performance and
sent, as assessed by the Mount Sinai Medical
diagnosis-specific hospital mortality rates, we strati-
Center Institutional Review Board. All authors vouch
fied the sample by admission diagnosis (primary
for the accuracy and completeness of the data
CCS diagnosis code). Within each subpopulation
presented.
multivariate logistic regression was conducted on
weighted numbers and was adjusted for patients’ age,
sex, race, insurance, income quartile by zip code,
number of chronic diseases, administration of diagnostic cardiac catheterization, administration of cardiac stress test, admission day, and APR-DRG severity
score. Diagnostic catheterization was adjusted for,
despite no significant difference observed between
the sample arms, because it could potentially portend
a mortality bias.
RESULTS
ANALYSIS OF TRENDS. An estimated 7,669,000 echo
examinations were performed in U.S. hospitals from
2001 to 2011. During this period, echo use grew at an
average annual rate of 3.41% (Central Illustration,
panel A). An evaluation of resource use and patients’
outcomes found that hospitalizations in which echo
was coded as the primary procedure had declining
rates of hospital mortality and length of stay. How-
SINGLE-CENTER VALIDATION ANALYSIS. To vali-
date our analysis of the NIS we evaluated all hospitalizations that occurred during the calendar year
2014 within our home institution, a large tertiary academic medical center in New York City. The
ICD-9-CM procedure code 88.72 was reported by
ever, these trends were associated with rising hospitalization charges (Central Illustration, panels B to D).
These trends motivated us to undertake a detailed
analysis for investigating whether underuse of echo
may be related with hospital outcomes and thus serve
as a marker of clinical care.
Mount Sinai hospital for reportable inpatient TTE
GEOGRAPHIC ECHO DISTRIBUTION. The highest rates
performed before October 1, 2015. The calendar year
of echo use per hospitalization were observed
2014
hospitalizations,
throughout the East Coast (Figure 1). On a state-by-state
among which we gated on the 8 admission diagnoses
basis, Rhode Island, New York, and Montana were
of interest and applied the same inclusion criteria as
the leading inpatient echo users, whereas the lowest
described earlier. The population was dichotomized
rates were observed in Wyoming, Alaska, and
by the performance or lack thereof inpatient echo,
New Mexico.
and demographic features were compared using
2010 NATIONWIDE INPATIENT SAMPLE AND SAMPLE
sample
contained
57,547
Student t tests and chi-square tests as appropriate.
DEMOGRAPHICS. Table 1 displays the 2010 NIS and the
We observed that the average age in the echo group
study population stratified by echo use and categor-
was advanced 11 years beyond that of the nonecho
ical variables. An estimated 816,500 echo exami-
group; this was markedly different from the age
nations
were
performed
nationally
in
2010,
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
CENTRAL I LLU ST RAT ION
Echocardiography Use in U.S. Hospitals
U.S. Hospital Trends in Echo Use: 2001 to 2011
Papolos, A. et al. J Am Coll Cardiol. 2016; 67(5):502–11.
(A) Annual national volume (shaded area) and incidence (dashed line) of echocardiography (echo) use per hospitalization. (B) Average charge of hospitalization in which echo was coded as the principal procedure performed versus the national average. (C) Average length of hospitalization in which echo
was coded as the principal procedure performed versus the national average. (D) Incidence of inpatient mortality of hospitalizations in which echo was
coded as the principal procedure performed versus the national average. LOS ¼ length of stay.
corresponding to 2.09% of all hospital admissions for
morbidity (p < 0.001), and had more chronic medical
that year. As expected, the proportion of hospi-
problems (p < 0.001) (Table 1).
talizations in which echo was performed was signifi-
SAMPLE ECHO RATES. The prevalence of echo use in
cantly higher within our sample (7.01%; p < 0.001).
the admission-diagnosis cohorts was as follows:
The distributions observed within categorical vari-
valvular disease (22%), acute cerebrovascular disease
ables were similar between the echo and nonecho
(12%), cardiac dysrhythmia (10%), CHF (7%), AMI
arms of our study population. However, significant
(6%), CAD (6%), sepsis (5%), and nonspecific chest
differences were observed across all domains, barring
pain (4%) (Figure 2). To explore the surprising low
use of diagnostic cardiac catheterization. In a com-
echo rates reported in patients with AMI and CAD, we
parison of the 2 sample arms, patients undergoing
scrutinized the uses of parallel imaging modalities
echo were younger (p < 0.001), received more cardiac
capable of providing a determination of ventricular
stress tests (p < 0.001), resided in higher-income zip
function. Rates of both cardiac stress testing and
codes (p < 0.001), were at higher risk of death and
cardiac magnetic resonance imaging were negligibly
505
506
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
F I G U R E 1 Echo Use per 100,000 Hospitalizations by State, 2010
Ontario
North Dakota
Idaho
New Hampshire
Massachusetts
Rhode Island
Delaware
New Jersey
District of Columbia
Alabama
MEXICO
The highest inpatient echocardiography (echo) use was seen in Rhode Island, New York, and Montana, whereas the lowest rates were observed
in Wyoming, Alaska, and New Mexico.
low, and cardiac computed tomography documenta-
SINGLE-CENTER VALIDATION ANALYSIS. Between
tion was variable. However, as expected, a large
2003 and 2014, the incidence of echo use per hospi-
proportion of the AMI and CAD cohorts underwent
talization at the Mount Sinai Medical Center steadily
diagnostic coronary catheterization (64% and 62%,
increased at an average annual rate of 4.75%. Echo
respectively) (Figure 2).
was performed during 14.6% of the 57,547 hospitalizations in 2014. Of these hospitalizations, 18,401 were
MORTALITY ANALYSIS. Multivariate logistic regres-
for 1 of the 8 admission diagnoses of interest and met
sion adjusting for key variables (age, sex, race, in-
the inclusion criteria previously described. Within
surance, income quartile by zip code, number of
this population we observed that the patients un-
chronic diseases, administration of diagnostic cardiac
dergoing echo were older (p < 0.001), more likely to
catheterization, and administration of cardiac stress
receive diagnostic coronary catheterization or stress
testing, admission day, and APR-DRG severity score)
testing (p < 0.001), and more critically ill (p < 0.001)
within each admission-diagnosis cohort was per-
(Online Table 1).
formed to evaluate for association between echo use
In our analysis of imaging practices in our home
and the odds of a patient’s death. We found that the
institution we observed underuse of echo for in-
use of echo was associated with significantly lower
dications identified in the NIS database (Table 2),
odds of all-cause hospital mortality in AMI (adjusted
most notably among patients with AMI, 25% of whom
OR: 0.74; 95% CI: 0.63 to 0.86; p < 0.001), cardiac
were discharged without echo evaluation and 17% of
dysrhythmia (adjusted OR: 0.72; 95% CI: 0.55 to 0.94;
whom were discharged without any form of cardiac
p ¼ 0.02), acute cerebrovascular disease (adjusted OR:
imaging. Death occurred in 9.4% of patients admitted
0.36; 95% CI: 0.31 to 0.42; p < 0.001), CHF (OR: 0.82;
for AMI, and the mortality rate was marginally higher
95% CI: 0.72 to 0.94; p ¼ 0.005), and sepsis (adjusted
in those patients in which echo was not performed
OR: 0.77; 95% CI: 0.70 to 0.85; p < 0.001). Significance
(10.1% vs. 9.1%), although this difference was not
was not observed in the subsamples for CAD (adjusted
statistically significant (p ¼ 0.14).
OR: 0.66; 95% CI: 0.40 to 1.08; p ¼ 0.09), valvular
The association between echo performance and the
disease (adjusted OR: 0.71; 95% CI: 0.40 to 1.25;
odds of inpatient mortality did not reach significance
p ¼ 0.24), or nonspecific chest pain (adjusted OR: 0.75;
in 6 of the remaining 7 admission diagnoses. Notably,
95% CI: 0.18 to 3.15; p ¼ 0.7) (Figure 3).
however,
42%
of
patients
who
died
during
Hospitalizations
Age, yrs
Sample
Without Echo
Echo
39,008,298
38,191,759
816,539
48.36 0.37
48.07 0.38
62.22 0.64
p Value
<0.001
Total
Without Echo
Echo
3,651,503
3,395,355
256,148
68.18 0.19
68.34 0.18
66.43 0.49
p Value
<0.001
Sex
Male
16,485,595 (42)
16,057,035 (42)
428,560 (52)
<0.001
1,825,729 (50)
1,689,377 (50)
136,352 (53)
<0.001
Female
22,436,406 (58)
22,048,547 (58)
387,859 (48)
<0.001
1,824,942 (50)
1,705,188 (50)
119,755 (47)
<0.001
White
22,564,721 (65)
22,116,303 (65)
448,417 (62)
0.0269
2,316,389 (69)
2,168,212 (70)
148,177 (63)
0.013
Black
5,577,833 (16)
5,428,059 (16)
149,774 (21)
562,055 (17)
513,749 (17)
48,306 (21)
Hispanic
4,219,597 (12)
4,148,024 (12)
71,574 (10)
287,797 (9)
264,819 (9)
22,977 (10)
Other
2,245,104 (6)
2,196,558 (6)
48,547 (7)
82,241 (2)
76,836 (2)
5,405 (2)
JACC VOL. 67, NO. 5, 2016
2010 NIS
Total
FEBRUARY 9, 2016:502–11
T A B L E 1 2010 NIS and Study-Sample Demographics*
Race
Payer
<0.001
Medicare
14,544,759 (37)
14,113,915 (37)
430,844 (53)
2,265,956 (62)
2,121,589 (63)
144,367 (56)
Medicaid
8,272,829 (21)
8,167,081 (21)
105,749 (13)
347,149 (10)
319,843 (9)
27,307 (11)
Private
1,2454,459 (32)
12,254,377 (32)
200,082 (25)
739,257 (20)
681,129 (20)
58,127 (23)
2,131,556 (5)
2,076,304 (5)
55,253 (7)
189,649 (5)
170,769 (5)
18,880 (7)
209,751 (1)
205,171 (1)
4,580 (1)
19,307 (1)
17,679 (1)
1,628 (1)
1,300,605 (3)
1,281,727 (3)
18,877 (2)
82,241 (2)
76,836 (2)
5,405 (2)
No
37,725,470 (97)
37,003,688 (97)
721,782 (88.4)
3,041,068 (83)
2,826,660 (83.2)
214,408 (83.7)
Yes
1,282,828 (3)
1,188,071 (3)
94,757 (11.6)
610,435 (17)
568,696 (16.8)
41,740 (16.3)
No
38,917,418 (99.8)
38,127,941 (99.8)
789,476 (96.7)
3,603,854 (99)
3,361,029 (99)
242,825 (94.8)
Yes
90,880 (0.2)
63,818 (0.2)
27,063 (3.3)
47,650 (1)
34,327 (1)
13,323 (5.2)
1–40,999
11,275,123 (30)
11,051,276 (30)
223,847 (29)
1,043,876 (29)
977,149 (30)
66,727 (27)
41,000–50,999
9,670,553 (25)
9,501,298 (26)
169,255 (22)
898,297 (25)
848,776 (26)
49,522 (20)
51,000–66,999
9,120,533 (24)
8,949,167 (24)
171,366 (22)
863,755 (24)
809,683 (24)
54,072 (22)
67,000þ
7,907,969 (21)
7,690,712 (21)
217,257 (28)
751,136 (21)
675,928 (20)
75,208 (31)
No
31,320,829 (80)
30,675,493 (80)
645,336 (79)
2,693,958 (74)
2,501,627 (74)
192,331 (75)
Yes
7,676,673 (20)
7,505,470 (20)
171,203 (21)
957,545 (26)
893,729 (26)
63,816 (25)
Self
No charge
Other
<0.001
Imaging
Diagnostic catheterization
<0.001
0.576
Stress test†
<0.001
<0.001
Income quartile, U.S. $
0.0027
<0.001
<0.001
<0.001
Severity index‡
<0.001
57,911 (0)
57,592 (0)
319 (0)
257 (0)
246 (0)
11 (0)
13,278,231 (34)
13,176,047 (34)
102,184 (13)
572,391 (16)
537,942 (16)
34,449 (13)
2
14,144,527 (36)
13,885,989 (36)
258,538 (32)
1,285,850 (35)
1,197,068 (35)
88,783 (35)
3
8,815,466 (23)
8,517,016 (22)
298,449 (37)
1,185,136 (32)
1,097,150 (32)
87,986 (34)
4
Number of chronic diseases
2,712,163 (7)
25,55,114 (7)
157,049 (19)
3.84 0.042
3.79 0.043
6.20 0.101
<0.001
607,868 (17)
562,949 (17)
44,919 (18)
6.4 0.053
6.38 0.054
6.72 0.107
<0.001
<0.001
Papolos et al.
0
1
Echocardiography Use in U.S. Hospitals
Weekend admission
Values are n, mean SE, or n (%). *p values comparing categorical variables between the echocardiography and nonechocardiography arms of each population were derived from Student t tests or chi-square test as appropriate. †Exercise and pharmacological cardiac
stress test. ‡All Patient Refined–Diagnosis Related Group severity score.
507
Echo ¼ echocardiography; NIS ¼ Nationwide Inpatient Sample.
508
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
F I G U R E 2 Sample Rates of Diagnostic Cardiac Catheterization and Echo by Admission Diagnosis
70%
Cath
Echo
60%
50%
40%
30%
20%
10%
0%
AMI
CAD
Nonspecific
chest pain
CHF
Dysrhythmia
Sepsis
Acute
Valvular heart
cerebrovascular
disease
disease
AMI ¼ acute myocardial infarction; CAD ¼ coronary artery disease; Cath ¼ cardiac catheterization; CHF ¼ congestive heart failure; Echo ¼
echocardiography.
hospitalization with reasons related to their primary
available all-payer inpatient database in the United
diagnosis did not undergo an echo examination
States suggests that echo maybe underused for com-
before death (Table 2).
mon and appropriate indications.
The cumulative use of parallel imaging modalities
capable of providing an assessment of cardiac function
NATIONAL ECHO USE. Between 2001 and 2011, the
other than echo (contrast ventriculogram, cardiac
absolute volume and incidence of echo per hospital-
computed tomography, radionuclide ventriculogram,
ization steadily increased at average annual rates of
cardiac magnetic resonance imaging, pharmacological
3.41% and 3.04%, respectively, less than one-half the
and nonpharmacological stress testing) per diagnosis
average annual growth rate described among Medi-
cohort were similar to our findings nationally (Online
care beneficiaries from 1999 to 2004 by Pearlman
Table 2). The reason for the lack of echo in these pa-
et al. (5). This discrepancy likely reflects differences
tients, however, could not be established during the
in study populations because our demographic was
analysis.
specific to the inpatient setting and pertained to an
all-payer population. This finding implies high rates
of echo use among Medicare beneficiaries in the
DISCUSSION
outpatient domain.
Widespread availability and familiarity with echo
performance per hospitalization was 2.09% in 2010,
have led to concern for its potential overuse.
which is consistent with an independent assessment
Recently, investigators have reported that echo use
of the NIS database reported previously (12). The
nearly doubled between 1999 and 2008 (6), consti-
geographic distribution of echo use was heteroge-
tuting approximately one-half of all cardiac imaging
neous, with the highest rates observed on the East
services among Medicare beneficiaries (5). Interest-
Coast. These results are consistent with previous re-
ingly, however, our analysis of the largest publicly
ports of echo use among Medicare beneficiaries in
Overall, the estimated national incidence of echo
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
1995 by Lucas et al (13). Although our analysis did not
lead to a definitive explanation for regional variation
F I G U R E 3 Adjusted Odds Ratio (95% CI) of In-Hospital Death in Patients Who
Underwent Echo by CCS Admission Diagnosis
in echo use, we speculate that this variation may
reflect geoeconomic disparities in access to health
Diagnosis
care, previously described geographic variation in
Cardiac Dysrhythmia
diagnostic practices, and elevated age-adjusted major
cardiovascular death rates in the region (14,15).
Acute Cerebrovascular Disease
CHF
MORTALITY
RATES
IN
PATIENTS
UNDERGOING
ECHO. In 2010, approximately one-half of all inpa-
tient echo examinations could be identified in the NIS
database during hospital admissions for AMI, cardiac
CAD
Sepsis
AMI
dysrhythmia, acute cerebrovascular disease, CHF,
CAD, sepsis, valvular disease, and nonspecific chest
pain. Adjusting for key variables, we observed that
Heart Valve Diseases
Nonspecific Chest Pain
the use of echo was associated with lower odds of
hospital mortality among 5 of these disease pro0.0
cesses. As the least expensive and lowest-risk cardiac
0.5
1.0
3.0
imaging modality available (16), echo is a first-tier
diagnostic tool that routinely leads to the initiation
Results control for age, sex, race, insurance, income quartile by zip code, number of
of various therapeutic interventions such as heart
chronic diseases, All Patient Refined–Diagnosis Related Group (APR-DRG) severity index,
failure regimens, use of implantable devices, surgery,
and revascularization, all of which have been shown
administration of cardiac catheterization and/or cardiac stress test, and admission day.
Cath ¼ coronary catheterization; CCS ¼ Clinical Classification Software (codes);
CI ¼ confidence interval; other abbreviations as in Figure 2.
to improve mortality rates in the appropriate clinical
setting (17). Although this study was not designed to
determine a causal link between echo and patients’
outcomes, we believe that the association observed
here is the product of information provided by echo
that assists physicians in management decisions and
patient risk stratification. This hypothesis is supported by a study conducted in a major academic
medical center, which found that 32% of inpatient
echo examinations led to an active change in medical
care (3). Extrapolation of this intervention rate could
explain the positive association observed in our
analysis.
The argument could be made that patients treated
in larger medical centers equipped with comprehen-
catheterization, and assuming that ejection fraction
was approximated by contrast ventriculography, an
assessment of cardiac function could not be substantiated in roughly 30% of this group. Although low
rates of echo use in the NIS database may reflect
underreporting because echo may not be required for
reimbursement
by
DRG
assignments
(non-DRG
procedures), the data continue to highlight underuse
of functional cardiac assessment, as reported in previous investigations. A population-based study of
2,317 patients hospitalized with myocardial infarction
from the Mayo Clinic in Minnesota reported that the
sive ancillary and diagnostic services would be more
likely to receive an echo examination and perhaps
T A B L E 2 Single-Center Echo Use Rates*
have access to more expert physicians. This position
would impose a significant bias toward echo use and
improved patient outcomes. For this reason we find it
Diagnosis
Echo Use
Echo Use in Patients
With Death Related to
Primary Diagnosis
important to convey that there was no difference in
CAD
1,287/3,439 (37)
79/131 (60)
the distribution of echo use among hospitalizations in
Dysrhythmia
1,587/3,704 (43)
115/208 (55)
small, medium, or large medical centers for the
CHF
927/1,744 (53)
58/81 (72)
Sepsis
514/1,467 (35)
108/220 (49)
16/29 (55)
admission diagnoses studied.
Acute cerebrovascular disease
380/734 (52)
DIAGNOSIS-SPECIFIC ECHO RATES. The use of echo for
NSCP
309/655 (47)
the initial evaluation and re-evaluation of ventricular
Valvular heart disease
525/1,011 (52)
35/52 (67)
function after acute coronary syndrome is in accor-
AMI
208/277 (75)
19/26 (73)
dance with current standards of care and is supported
by appropriate use criteria (1). However in 2010, echo
was identified in only 6.2% of our AMI cohort. Within
this cohort, 64% underwent diagnostic coronary
7/7 (100)
Values are n/N (%). *Admission diagnosis–specific rates of echo use within our single-center
sample and among the subpopulation of admissions in which inpatient death occurred.
AMI ¼ acute myocardial infarction; CAD ¼ coronary artery disease; CHF ¼ congestive heart
failure; Echo ¼ echocardiography; NSCP ¼ nonspecific chest pain.
509
510
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
use of echo within the first 30 days after AMI
database, the NIS data are subject to potential over-
increased from 14% in 1979 to 65% by 1986 (18).
sights in documentation and coding. The low use of
Another study from Olmsted County, Minnesota
echo in the NIS database may simply represent insti-
compiled features of 791 patients who developed
tutional underreporting of ICD-9-CM procedure cod-
heart failure after AMI and reported that left ven-
ing in the inpatient claim data. Because the database
tricular function was not assessed after the diagnosis
comprises survey-level data of de-identified dis-
of heart failure in 38% of patients (19). More recently,
charge information, coding inaccuracy, coding preci-
data from the Worcester Heart Attack Study reported
sion, and readmission data cannot be corrected for.
that in 2003, echo was used in slightly more than 50%
Indications for echo administration are not recorded
of patients hospitalized for AMI and that ejection
in the NIS, so admission diagnosis was used as a
fraction was not assessed among 27% of patients
surrogate. The NIS does not provide information
before discharge (20).
about survival beyond the inpatient period; hence,
We attempted to investigate AMI-related cardiac
longer-term outcomes are unknown. Finally, the
imaging practices in our home institution. In our
sample size of our single-center validation cohort was
sample of 277 admissions to the Mount Sinai Medical
underpowered to demonstrate a significance associ-
Center in 2014 for AMI, we found that 75% of these
ation between echo and mortality; larger prospective
patients
studies are needed.
underwent
echo,
and
41%
underwent
another mode of cardiac imaging, primarily coronary
artery catheterization. We found that 17% of patients
admitted for AMI were discharged without an
assessment of cardiac function. Of these 277 hospitalizations, 26 were associated with the patient’s
death (9.4%), and among those who died, cardiac
imaging was not performed in 27%.
Similarly, the appropriate use criteria support the
re-evaluation of cardiac function by echo among patients with heart failure, arrhythmia, and known
valvular disease in the event of a change in clinical
status without a clear precipitant (1). In our nationally
representative sample, rates of echo use among patients requiring hospitalization with these admission
diagnoses ranged from 7% to 22%.
We confirmed our observation that echo is underused on the national level by demonstrating the
underuse of echo in a tertiary care referral center
located in one of the most diagnostically advanced
regions in the United States. However, multivariate
mortality analysis of our single-center cohort did not
reach statistical significance.
Low rates of echo performance observed nationally
may in part be explained by the diagnostic stewardship of physicians or by cost bundling agreements
between insurance companies and hospitals that
place extra incentives to shift inpatient procedures
CONCLUSIONS
Echo use was associated with decreased odds of
hospital mortality among 5 of the leading 6 admission
diagnoses for which echo was most commonly
reported in the 2010 NIS database. These 5 diagnoses
account
for
approximately
3.7
million
national
hospitalizations annually; however, in 2010 the NIS
database reported echo use in only 8% of cases.
Because patient selection and appropriate echo use
are key to cost efficiency, this study suggests that
echo may be underused during critical cardiovascular
hospitalizations, most notably in the treatment
of AMI.
REPRINT REQUESTS AND CORRESPONDENCE: Dr.
Partho P. Sengupta, Mount Sinai’s Zena and Michael A.
Wiener
Cardiovascular
Institute,
Marie-Josée
Gustave L. Levy Place, New York, New York 10029.
E-mail: [email protected].
PERSPECTIVES
COMPETENCY IN SYSTEMS-BASED PRACTICE:
Patients hospitalized with myocardial infarction, heart
failure, cardiac dysrhythmia, acute cerebrovascular
into the post-discharge outpatient domain.
ischemia, or sepsis who underwent echo faced a lower
STUDY LIMITATIONS. Considerable caution is required
in interpreting the results of the study. Information in
the
NIS
is
generated
from
discharge
abstracts
designed to facilitate hospital payment. These abstracts customarily are prepared by trained coding
specialists after reviewing inpatient medical records
to capture provider care and services that warrant
reimbursement. Just as in any other administrative
and
Henry R. Kravis Center for Cardiovascular Health, One
likelihood of inpatient mortality than did patients
without echo.
TRANSLATIONAL OUTLOOK: Further studies are
required to clarify the links between access to echo
and clinical outcomes among hospitalized patients in
the United States.
Papolos et al.
JACC VOL. 67, NO. 5, 2016
FEBRUARY 9, 2016:502–11
Echocardiography Use in U.S. Hospitals
REFERENCES
1. Douglas PS, Khandheria B, Stainback RF, et al.
ACCF/ASE/ACEP/AHA/ASNC/SCAI/SCCT/SCMR 2008
appropriateness criteria for stress echocardiography:
a report of the American College of Cardiology
Foundation Appropriateness Criteria Task Force,
American Society of Echocardiography, American
College of Emergency Physicians, American Heart
Association, American Society of Nuclear Cardiology, Society for Cardiovascular Angiography
and Interventions, Society of Cardiovascular
Computed Tomography, and Society for Cardiovascular Magnetic Resonance Endorsed by the
Heart Rhythm Society and the Society of Critical
Care Medicine. J Am Coll Cardiol 2008;51:
1127–47.
2. Ballo P, Bandini F, Capecchi I, et al. Application
of 2011 American College of Cardiology Foundation/American Society of Echocardiography
appropriateness use criteria in hospitalized patients referred for transthoracic echocardiography
in a community setting. J Am Soc Echocardiogr
2012;25:589–98.
3. Matulevicius S, Rohatgi A, Das S, Price AL,
DeLuna A, Reimold S. Appropriate use and clinical
impact of transthoracic echocardiography. JAMA
Intern Med 2013;173:1600–7.
4. Patil HR, Coggins TR, Kusnetzky LL, Main ML.
Evaluation of appropriate use of transthoracic
echocardiography in 1,820 consecutive patients
using the 2011 revised appropriate use criteria for
echocardiography. Am J Cardiol 2012;109:1814–7.
5. Pearlman AS, Ryan T, Picard MH, Douglas PS.
Evolving trends in the use of echocardiography: a
study of Medicare beneficiaries. J Am Coll Cardiol
2007;49:2283–91.
6. Andrus BW, Welch HG. Medicare services provided by cardiologists in the United States: 1999–
2008. Circ Cardiovasc Qual Outcomes 2012;5:31–6.
7. Okrah K, Vaughan-Sarrazin M, Cram P. Trends in
echocardiography utilization in the Veterans
Administration Healthcare System. Am Heart J
2010;159:477–83.
8. Healthcare Cost and Utilization Project. Facts
and Figures: Statistics on Hospital-Based Care in
the United States 2010. Available at: https://www.
hcup-us.ahrq.gov/db/nation/nis/NIS_Introduction_
14. Song Y, Skinner J, Bynum J, Sutherland J,
Wennberg JE, Fisher ES. Regional variations in
diagnostic practices. N Engl J Med 2010;363:45–53.
2010.jsp. Accessed September 20, 2014.
15. Go A, Mozaffarian D, Roger V, et al. Heart
disease and stroke statistics—2013 update: a
report from the American Heart Association. Circulation 2013;127:143–52.
9. Whalen D, Houchens R, Elixhauser A. 2004
HCUP Nationwide Inpatient Sample (NIS) Comparison Report. HCUP Methods Series Report
16. Ferrari VA, Whitman B, Blankenship JC, et al.
Cardiovascular imaging payment and reimbursement systems: understanding the past and present
#2007-03. Online February 2, 2007. U.S.
Agency for Healthcare Research and Quality.
Available at: https://www.hcup-us.ahrq.gov/db/
nation/nis/reports/2004niscomparisonrpt.jsp. Accessed September 20, 2014.
in order to guide the future. J Am Coll Cardiol Img
2014;7:324–32.
10. Healthcare
Cost
and
Utilization
Project.
Agency for Healthcare Research and Quality,
Rockville, MD. 1999–2011. Available at: http://
hcupnet.ahrq.gov/HCUPnet.jsp?Id¼DB97390A368
039A9&Form¼SelLAY&JS¼Y&Action¼%3E%3ENext
%3E%3E&_LAY¼Researcher. Accessed September
20, 2014.
11. Averill R, Goldfield N, Hughes J, et al. 3M
APR-DRG Classification System Version 26.1
(effective 10/01.2008) Methodology Overview.
3M Health Information Systems. Wallingford, CT.
2008. Available at: http://www.hcup-us.ahrq.
gov/db/nation/nis/v261_aprdrg_meth_ovrview.pdf.
Accessed September 20, 2014.
12. Pfuntner A, Wier LM, Stocks C. Most Frequent
Procedures Performed in U.S. Hospitals, 2010:
Statistical Brief #149. In: Healthcare Cost and
Utilization Project (HCUP) Statistical Briefs
[Internet]. Available at: http://www.ncbi.nlm.nih.
gov/books/NBK132428/. Accessed November 8,
2015.
13. Lucas FL, Wennberg DE, Malenka DJ. Variation
in the use of echocardiography. Eff Clin Pract
1999;2:71–5.
17. Yancy C, Jessup M, Bozkurt B, et al. 2013
ACCF/AHA guideline for the management of heart
failure: executive summary: a report of the
American College of Cardiology Foundation/
American Heart Association Task Force on Practice
Guidelines. J Am Coll Cardiol 2013;62:1506–22.
18. Lopez-Jimenez F, Goraya TY, Hellermann JP,
et al. Measurement of ejection fraction after
myocardial infarction in the population. Chest
2004;125:397–403.
19. Hellermann JP, Jacobsen SJ, Redfield MM,
Reeder GS, Weston SA, Roger VL. Heart
failure after myocardial infarction: clinical presentation and survival. Eur J Heart Fail 2005;7:
119–25.
20. Santolucito PA, Tighe DA, Lessard D, et al.
Changing trends in the evaluation of ejection
fraction in patients hospitalized with acute
myocardial infarction: the Worcester Heart Attack
Study. Am Heart J 2008;155:485–93.
KEY WORDS echocardiography,
national trends
A PP END IX For supplemental tables, please
see the online version of this article.
511