Agency for Healthcare Research and Quality
Advancing Excellence in Health Care • www.ahrq.gov
Hospital Readmissions, Cost/Year
and Multiple Chronic Conditions
Bernard Friedman
Joanna Jiang
Anne Elixhauser _
June 25, 2006
1
Objectives

Examine “complexity” of chronic illness (number
of different chronic conditions) in relation to:
number of admissions per person in a year
 total cost per person over a year


Test and control for other contributing factors


patient, hospital, area characteristics
Compare persons with “early” readmissions
(within 30 days) vs. persons with other
readmissions
2
Background




IOM, Chasm study (2001): “optimizing care for
patients with several chronic conditions…an
extraordinary challenge...”
Literature on Disease Management gives mixed results
and modest savings (CBO, 2004)
Some optimistic demonstrations on coordination of
care for chronic illness (Friese, 1998; Chen 2000)
Recent pessimism about Medicare demonstrations for
chronically ill (Gold, 2005)
3
Targeting Interventions
Health plans are concerned about cost of opening the benefits to
new types of services for chronic illness.

Suggestion from our recent study (MCRR, 2006): target
persons when initial hospital stay indicates 3, 5 or more different
chronic conditions.

But how many of observed stays are actually readmissions?


What proportion of persons have X+ different chronic conditions when
first hospitalized?
How many readmissions occur afterward and at what cost?
4
Population and Data Sources

HCUP State Inpatient Databases for:
California
 Nebraska
 New York
 Pennsylvania
 Tennessee
 Utah



Adults, hospitalized during Jan.-Nov. 2002
No maternity-related stays
5
Measurement Issues

Chronic versus non-chronic conditions at ICD-9-CM level


http://www.hcup-us.ahrq.gov/toolssoftware/chronic/chronic.jsp
Grouped to identify “different” chronic conditions

no more than one per Clinical Classification Software (CCS) or CCS
cluster

Hospital cost: CCR based on accounting reports to CMS

Person identity: supplied by states and verified (age, gender)

Episodes -- include same-day transfers to another hospital

Cannot observe death outside hospital
6
Definitions of chronic condition



Lasts at least 12 months or longer AND
Places limitations on task performance, self-care,
independent living, social interactions OR
Results in need for ongoing medical intervention (meds,
therapy, special equipment, special schooling, protocols
affecting diet or activity


Hwang et al.
Concurrent diseases that impose additional clinical
vulnerability in the patients, and that may in turn, influence
resource use

Silber et al.
7
Measurement Issues

Chronic versus non-chronic conditions at ICD-9-CM level


http://www.hcup-us.ahrq.gov/toolssoftware/chronic/chronic.jsp
Grouped to identify “different” chronic conditions

no more than one per Clinical Classification Software (CCS) or CCS
cluster

Hospital cost: CCR based on accounting reports to CMS

Person identity: supplied by states and verified (age, gender)

Episodes -- include same-day transfers to another hospital

Cannot observe death outside hospital
8
Overview of Study Population
No readmissions
N (%)
Any readmission
3,517,898 (79.8%)
889,310 (20.2%)
N readmissions
0
1.51
Hospital cost/yr
$7,377
$19,641
Days in hospital
5.7
16.9
N chronic conditions
2.9
3.6
20.6%
31.4%
59.4
64.1
Female
55.0%
53.5%
APR-DRG 3-4
17.3%
27.6%
Elective admission
26.7%
19.0%
Major ther. procedure
36.2%
23.7%
% with 5+ chronic conditions
Age, years
9
Characteristics of Patients with
Readmissions
Early readmit
Readmit > 30d
both
376 (42.3%)
358 (40.2%)
155 (17.4%)
N readmissions
1.29
1.13
2.92
Hospital cost/yr
$18,681
$15,925
$30,629
Days in hospital
16.6
13.2
26.1
N chronic conditions
3.5
3.6
3.8
% with 5+ chronic cond.
30.7%
30.3%
35.4%
Age
63.8%
64.5%
63.8%
Female
52.7%
54.6%
52.7%
Severity level 3 or 4
29.4%
24.1%
31.1%
Elective admission
18.3%
21.3%
15.7%
Major ther. procedure
20.0%
18.4%
20.4%
N in 1000s (%)
10
Risk of Readmission by
Principal Diagnosis at Index Admission
Principal Diagnosis at
Index Admission
Persons
(1000s)
Risk of any
readmit
RR early vs.
other readmit
Mental disorders
Malignancy
Coronary atherosclerosis
Pneumonia
357
304
244
227
40.7%
42.5%
38.9%
42.6%
0.21
0.27
0.24
0.20
CHF
Stroke
Chest pain
223
203
188
59.4%
33.3%
27.9%
0.16
0.25
0.17
Asthma
Conduction/dysrhythmia
AMI
181
168
139
48.8%
39.1%
36.2%
0.17
0.21
0.36
11
Multivariate Regression:
Adjusted Cost per person in 2002

Cost of each episode divided by index of relative cost of
discharge with the principal DX

Then Adjusted Cost is summed over episodes

Semi-log model
 log(Adj. Cost)= α*log(Wage) + β*log(months)
+ linear {X}
12
Influences on Cost/Person,
Based on Multivariate Model
Patient Level
Months observed
Severity of illness
Medicare or Medicaid
Self-pay
Secondary cancer dx
Secondary HTN dx
Secondary DM dx
Hospital Level
% admitted from ED
+ Wage index (hospital area)
+ Large hospital
+ Investor-owned hosp
 Teaching hosp
+ Safety indicators (hosp)
+
Area Level
+ N hosp beds (area)
N primary care MDs (area)
Quality indicators (area)

+
ns
+
+
ns
ns
ns
13
ns
Percent Increase in Cost per Person, by
Number of Chronic Conditions
N of different chronic
conditions
% increase in cost
for year
2
% of cases
18.5
3
17.1
7.6
4
14.4
9.6
5
10.4
11.0
6
6.4
13.2
7+
5.8
17.9
6.4
Persons=774,000; hospitals=1029, all results P<.001
14
Simulation of Potential Savings




If the cost and readmissions for adults with 5+ different
chronic conditions were reduced to level of other adults
Target: 23% of all defined adults first admitted during
Jan-Nov. of 2002.
Control for all other determinants in the regressions.
Potential savings:


$3,548 per person in target group (9% of total resource costs
for entire population covered)
Extrapolated national savings: $22.7 billion in hospital costs
15
Issues

Number of chronic conditions
Some may not be diagnosed at the index admission
 Some may be known but not recorded
 Some may emerge during the year



Lost some persons due to death outside the
hospital.
Additional tests of model specification.
16
Discussion



Hospital admission is a prime opportunity for
systematic and thorough diagnosis
Even “early” readmissions are associated with
complexity of chronic conditions
Meaningful potential savings within a year


How? educational services, pharmacy guidance,
“coordination” (Lorig; Chen)
Limited number of persons in target population
17