A Refined Approach to Evaluating Hospital
Readmission Rates: Accounting for
Multiple Visits to the ED for Potentially
Preventable Conditions
Claudia Steiner, MD, MPH
Agency for Healthcare Research and Quality
AcademyHealth • June 2009
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Study Topic
Assess the impact of including both
IP and ED data when evaluating potentially
preventable admissions and visits
Previous research only considers IP data
Friedman B., Basu J. The Rate and Cost of Hospital Readmissions for
Preventable Conditions. Med Care Res Rev 2004; 61; 225
2
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Objectives
 Understand the impact of including both IP
and ED data when evaluating the utilization
and costs of potentially preventable
healthcare encounters
 Evaluate the additional utilization / cost impact
of factoring in revisits to the hospital and/or
ED by the same person for selected
potentially preventable health care encounters
3
Study Design
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 Design: retrospective, observational cohort
study
 Timeframe: 23-months
(January 2005 – November 2006)
 Four states: AZ, NE, NY, and TN
4
Study Design
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 Design: retrospective, observational cohort
study
 Timeframe: 23-months
(January 2005 – November 2006)
 Four states: AZ, NE, FL, and TN
5
Three Primary
AHRQ Resources
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Prevention Quality Indictors
(Asthma {pediatric, adult, elderly}, Diabetes
{pediatric, adult}, CHF, Bacterial
Pneumonia, and Pediatric Gastroenteritis )
Quality
Measures
HCUP State Inpatient Databases
SID
(AZ, NE, FL, TN)
HCUP State ED Databases
SEDD
6
(AZ, NE, FL, TN)
Hospital
discharge
databases
Study Design
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 HCUP SID
–
–
Encounter / discharge level
All discharges from all community hospitals in participating
states
 HCUP SEDD
–
–
Encounter / visit level
All treat and release encounters from all community hospital
emergency departments in participating states
 AHRQ PQIs
–
–
–
7
Applied the standard definitions (numerators and
denominators) provided by the software package available
through AHRQ
Each condition defined using the principle diagnosis field
Readmissions limited to the same condition
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Readmissions: Related
Admissions for Same Patient
1 hospital admission
3 hospital admissions from 2
unique people in SID
2006 SID
2 hospital admissions
Readmissions: Sequential hospital admissions for a
related reason, and usually within a specific time frame.
8
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Revisits: Multiple visits for same
patient across hospital settings
1 hospital admission + 2 ED visits
3 hospital admissions +
3 ED visits from 2 unique
people
2006 SID
2 hospital admissions + 1 ED visit
9
2006 SEDD
Revisits: Multiple health care encounters for a
particular patient for a potentially preventable admission
or ED visit.
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Early Study Results:
Across 4 States - Utilization
Selected Prevention
Quality Indicators
ASTHMA
Total
Events
Total Pts
%
Events
%
Revisit
IP events
47,274
38,766
19.12
13.03
ED events
199,986
134,227
80.88
21.23
Combined IP and ED events
247,260
165,208
100.00
21.26
DIABETES IP events
40,395
32,748
75.90
11.45
ED events
12,828
11,222
24.10
10.15
Combined IP and ED events
53,223
42,438
100.00
12.89
IP events
211,204
162,839
88.82
18.57
ED events
26,598
23,257
11.18
9.80
237,802
178,671
100.00
19.78
IP events
201,521
184,451
72.13
7.67
ED events
77,849
74,101
27.87
4.52
279,370
253,137
100.00
8.49
IP events
580,113
473,548
49.35
14.42
ED events
595,410
468,848
50.65
14.77
1,175,523
905,755
100.00
16.84
CHF
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
10
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Early Study Results:
Across 4 States - Utilization
Selected Prevention
Quality Indicators
ASTHMA
Total
Events
Total Pts
%
Events
%
Revisit
IP events
47,274
38,766
19.12
13.03
ED events
199,986
134,227
80.88
21.23
Combined IP and ED events
247,260
165,208
100.00
21.26
DIABETES IP events
40,395
32,748
75.90
11.45
ED events
12,828
11,222
24.10
10.15
Combined IP and ED events
53,223
42,438
100.00
12.89
IP events
211,204
162,839
88.82
18.57
ED events
26,598
23,257
11.18
9.80
237,802
178,671
100.00
19.78
IP events
201,521
184,451
72.13
7.67
ED events
77,849
74,101
27.87
4.52
279,370
253,137
100.00
8.49
IP events
580,113
473,548
49.35
14.42
ED events
595,410
468,848
50.65
14.77
1,175,523
905,755
100.00
16.84
CHF
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
11
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Early Study Results:
Across 4 States - Utilization
Selected Prevention
Quality Indicators
ASTHMA
Total
Events
Total Pts
%
Events
%
Revisit
IP events
47,274
38,766
19.12
13.03
ED events
199,986
134,227
80.88
21.23
Combined IP and ED events
247,260
165,208
100.00
21.26
DIABETES IP events
40,395
32,748
75.90
11.45
ED events
12,828
11,222
24.10
10.15
Combined IP and ED events
53,223
42,438
100.00
12.89
IP events
211,204
162,839
88.82
18.57
ED events
26,598
23,257
11.18
9.80
237,802
178,671
100.00
19.78
IP events
201,521
184,451
72.13
7.67
ED events
77,849
74,101
27.87
4.52
279,370
253,137
100.00
8.49
IP events
580,113
473,548
49.35
14.42
ED events
595,410
468,848
50.65
14.77
1,175,523
905,755
100.00
16.84
CHF
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
12
Early Study Results:
Across 4 States - Cost
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Selected Prevention Quality
Indicators
ASTHMA
Total
Events
Total Cost
Avg Cost
IP events
47,274
$
255,118,826
$
6,581
ED events
199,986
$
71,126,788
$
530
Combined IP and ED events
247,260
$
326,245,614
$
1,975
DIABETES IP events
40,395
$
263,599,350
$
8,049
ED events
12,828
$
7,598,448
$
677
Combined IP and ED events
53,223
$
271,197,798
$
6,390
$ 1,842,724,238
$
11,316
$
23,206,632
$
998
237,802
$ 1,865,930,870
$
10,443
IP events
201,521
$ 1,695,780,779
$
9,194
ED events
77,849
$
52,331,894
$
706
279,370
$ 1,748,112,673
$
6,906
IP events
580,113
$ 4,390,437,514
$
9,271
ED events
595,410
$
242,859,457
$
518
$ 4,633,296,972
$
5,115
CHF
IP events
211,204
ED events
26,598
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
13
1,175,523
Early Study Results:
Across 4 States - Cost
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Selected Prevention Quality
Indicators
ASTHMA
Total
Events
Total Cost
Avg Cost
IP events
47,274
$
255,118,826
$
6,581
ED events
199,986
$
71,126,788
$
530
Combined IP and ED events
247,260
$
326,245,614
$
1,975
DIABETES IP events
40,395
$
263,599,350
$
8,049
ED events
12,828
$
7,598,448
$
677
Combined IP and ED events
53,223
$
271,197,798
$
6,390
$ 1,842,724,238
$
11,316
$
23,206,632
$
998
237,802
$ 1,865,930,870
$
10,443
IP events
201,521
$ 1,695,780,779
$
9,194
ED events
77,849
$
52,331,894
$
706
279,370
$ 1,748,112,673
$
6,906
IP events
580,113
$ 4,390,437,514
$
9,271
ED events
595,410
$
242,859,457
$
518
$ 4,633,296,972
$
5,115
CHF
IP events
211,204
ED events
26,598
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
14
1,175,523
Early Study Results:
Across 4 States - Cost
Advancing
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Selected Prevention Quality
Indicators
ASTHMA
Total
Events
Total Cost
Avg Cost
IP events
47,274
$
255,118,826
$
6,581
ED events
199,986
$
71,126,788
$
530
Combined IP and ED events
247,260
$
326,245,614
$
1,975
DIABETES IP events
40,395
$
263,599,350
$
8,049
ED events
12,828
$
7,598,448
$
677
Combined IP and ED events
53,223
$
271,197,798
$
6,390
$ 1,842,724,238
$
11,316
$
23,206,632
$
998
237,802
$ 1,865,930,870
$
10,443
IP events
201,521
$ 1,695,780,779
$
9,194
ED events
77,849
$
52,331,894
$
706
279,370
$ 1,748,112,673
$
6,906
IP events
580,113
$ 4,390,437,514
$
9,271
ED events
595,410
$
242,859,457
$
518
$ 4,633,296,972
$
5,115
CHF
IP events
211,204
ED events
26,598
Combined IP and ED events
B. PNEU
Combined IP and ED events
All 8 Conditions
Combined
IP and ED events
15
1,175,523
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Which PQIs were most impacted
by adding ED data?
Percent of visits that were treatand-release ED visits versus IP
admissions:








16
Pediatric gastroenteritis (83%)
Asthma, Pediatric (82%)
Asthma, Adult (81%)
Asthma, Elderly (41%)
Bacterial pneumonia (28%)
Diabetes, Adult (24%)
Diabetes, Pediatric (20%)
Congestive heart failure (11%)
Greatest ED impact
on utilization
Pediatric
gastroenteritis and
Non-elderly asthma
Lowest ED impact on
utilization
CHF
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Which PQIs had the most multiple
visits (revisits)?
Percent of patients with more than
one visit to the hospital and/or ED:








17
Asthma, Adult (21%)
Asthma, Pediatric (20%)
Congestive heart failure (20%)
Diabetes, Pediatric (18%)
Asthma, Elderly (14%)
Diabetes, Adult (13%)
Bacterial pneumonia (8%)
Pediatric gastroenteritis (8%)
Greatest % of
revisits
Non-elderly
asthma and CHF
Lowest % of
revisits
Bacterial
pneumonia &
Pediatric
gastroenteritis
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TN: Insured vs. Uninsured
%
Patients
# of
visits
% any
revisit
within
one
month
CHF
Uninsured* for at least one
event
3.96%
2975
16.02%
Always insured
96.04%
56,268
10.89%
19.92%
8459
12.00%
80.08%
28,139
7.34%
ASTHMA
Uninsured* for at least one
event
Always insured
18
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TN: Insured vs. Uninsured
%
Patients
Total IP
Costs
Total ED
Costs
Total IP and
ED Costs
CHF
Uninsured* for at least one
event
3.96%
$14,285,180
$ 567,265
$ 14,852,444
Always insured
96.04%
$289,117,809
$7,774,937
$296,892,746
19.92%
$4,049,520
$2,433,391
$6,482,910
80.08%
$26,184,123
$7,378,520
$33,562,643
ASTHMA
Uninsured* for at least one
event
Always insured
19
Limitations
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 Limited generalizability of results
 Encrypted patient number not available on
HCUP national databases
– Nationwide Inpatient Sample (NIS)
– Nationwide Emergency Department Sample
(NEDS)
20
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Conclusions
 Substantial impact of ED visits on overall
hospital utilization for eight potentially
preventable admissions
– Accounting for ED visits more than doubled the
number of visits (by 580K)
 Variable impact of ED visits on overall
hospital costs for eight potentially preventable
admissions
– Increased overall costs by 6% (by $243M)
21
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Conclusions
 Patients treated in the ED had more revisits
for the same condition than patients seen in
the IP setting: the additional ED visit data
increased the overall re-visit percentage
by 17%.
 ED impact is condition specific: high for
asthma, low for diabetes
22
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Implications
 Because a substantial portion of re-visits
manifest as ED encounters, these findings
caution against the sole use of inpatient
admission and readmission rates as an
indicator of hospital cost, quality and access,
without accounting for patient visits to the ED
 Findings provide insights to policy-makers
and payers when designing strategies to
reduce visits for potentially preventable
conditions
23
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Project Team
 Claudia Steiner, MD, MPH
 Barry Friedman, PhD
 Joanna Jiang, PhD
 Dan Whalen
 Marguerite Barrett, MS
 Minya Sheng
 Chaya Merrill, PhD
24
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Healthcare Cost and
Utilization Project (HCUP)
THE LARGEST COLLECTION OF MULTI-LEVEL,
ALL-PAYER, ENCOUNTER-LEVEL, HEALTH CARE DATA
25
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Verifying PNUMS
Combined 2005-2006
SID, SASD, and
SEDD within state
Sorted by
PNUM_R,
date of birth,
and gender
Assign VisitLink
for unique
patient combo
PNUM_R
NC SID
15
States
with
PNUM
DOB
NC SASD
NY SASD
PNUM_R
FEMALE
DOB
PNUM_R
NY SEDD
DOB
FEMALE
VisitLink
FEMALE
NY SID
PNUM_R
DOB
AZ SID
26
VisitLink
AZ SEDD
FEMALE
VisitLink
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Hospital “Readmissions”
Hospital readmission rates can be an important
indicator of the quality of medical care
27
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A Method for Tracking
Multiple Visits by the Same Patient
AHRQ created supplemental linkable files that can
be used with the HCUP state-level databases to
track sequential visits for an individual patient
across facilities, settings, and time.
SID
SEDD
28
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Revisits: Multiple visits for same
patient across hospital settings
1 ambulatory surgery + 1 hospital
admission + 2 ED visits
1 ambulatory surgery visit +
3 hospital admissions +
3 ED visits from 2 unique
people
2006 SID
2006 SASD
2 hospital admissions + 1 ED visit
29
2006 SEDD
Revisits: Multiple health care encounters for a
particular patient for any reason and can be separated
by days or years.