Skip to main content

Table 3 Evidence for adding functioning information into casemix systems

From: Capturing patients’ needs in casemix: a systematic literature review on the value of adding functioning information in reimbursement systems

Author and year

Study characteristics a

Setting & sample size b

Type of casemix

Model(s)

Key results c

Costs

 Covinsky et al. (1997)

a1, b3, c1, d3

General medical service at a teaching hospital n = 823

DRG

hospitalization costs:

hospitalization costs (measured in units):

Model 1*: Dependent in 0 ADL

Model 1: 100

Model 2: Dependent in 1–3 ADLs

Model 2: 112 (99–126)

Model 3: Dependent in 4–5 ADLs

Model 3: 142 (125–162)

Model 4: Dependent in 6 ADLs

Model 4: 150 (131–172)

* all models controlled for Acute Physiology Score, Charlson score, age, race, gender, admission from nursing home and diagnosis related group cost weight

 

 Evers et al. (2002)

a2, b2, c1, d2

Hospital n = 731

DRG

Explained variance in costs directly related to medical care:

Explained variance costs directly related to medical care (R2):

Total costs:

Total costs:

Model 1: DRGs

Model 1: 0.338

Model 2: DRGs + Need factors (includes functioning information among others)

Model 2: 0.547

Model 3: DRGs + Need factors + Enabling factors + Predisposing factors + First order interactions (includes interactions between functioning and gender)

Model 3: 0.611

Diagnostic costs:

Diagnostic costs:

Model 1: DRGs

Model 1: 0.168

Model 2: DRGs + Need factors (includes functioning information among others)

Model 2: 0.362

Model 3: DRGs + Need factors + Enabling factors + Predisposing factors + First order interaction (includes interactions between functioning and gender)

Model 3: 0.407

Therapeutic costs:

Therapeutic costs:

Model 1: DRGs

Model 1: 0.377

Model 2: DRGs + Need factors (includes functioning information among others)

Model 2: 0.483

Model 3: DRGs + Need factors + Enabling factors + Predisposing factors + First order interactions (includes interactions between functioning and gender)

Model 3: 0.533

 Chuang et al. (2003)

a2, b3, c2, d3

General medical service at a teaching hospital n = 1612

DRG

Hospital costs:

Hospital costs (in $):

All patients:

All patients:

Model 1: Independent in ADL on admission

Model 1: $4,060

Model 2: Dependent in ADL on admission

Model 2: $5,300

DRG weight <0.9:

DRG weight <0.9:

Model 1: Independent in ADL on admission

Model 1: $3,090

Model 2: Dependent in ADL in admission

Model 2: $4,130

DRG weight 0.9-1.0:

DRG weight 0.9-1.0:

Model 1: Independent in ADL on admission

Model 1: $3,560

Model 2: Dependent in ADL on admission

Model 2: $4,440

DRG weight 1.0-1.2:

DRG weight 1.0–1.2:

Model 1: Independent in ADL on admission

Model 1: $3,940

Model 2: Dependent in ADL on admission

Model 2: $4,840

DRG weight >1.2:

DRG weight >1.2:

Model 1: Independent in ADL on admission

Model 1: $6,560

Model 2: Dependent in ADL on admission

Model 2: $8,250

All patients adjusted for DRG weight:

All patients adjusted for DRG weight:

Model 1: Independent in ADL on admission

Model 1: $4,140

Model 2: Dependent in ADL on admission

Model 2: $5,240

All patients adjusted for age, race, sex, Charlson Comorbidity score, APACHE II score, admission from nursing home and DRG weight:

All patients adjusted for age, race, sex, Charlson Comorbidity score, APACHE II score, admission from nursing home and DRG weight:

Model 1: Independent in ADL on admission

Model 1: $4,220

Model 2: Dependent in ADL on admission

Model 2: $5,200

 Pietz et al. (2004)

a2, b3, c3, d1

VA medical centers primary care patients n = 35337

ACG-based ADGs

Model’s ability to predict costs for FY 1998 and FY 1999:

Models ability to predict costs for FY 1998 and FY 1999 (R2):

Cost 1998:

Cost 1998:

Model 1: ACGs

Model 1: 0.277

Model 2: age, gender, ADGs, PCS, MCS,

Model 2: 0.294

Model 3: age, gender, ADGs, 8 items

Model 3: 0.298

Cost 1999:

Cost 1999:

Model 1: ACGs

Model 1: 0.070

Model 2: age, gender, ADGs, PCS, MCS,

Model 2: 0.085

Model 3: age, gender, ADGs, 8 items

Model 3: 0.087

MAPE for costs 1999:

MAPE for 10th decile for costs 1999:

Model 1: age, gender, ADGs

Model 1: $23440

Model 2: age, gender, ADGs, 8 items

Model 2: $23204

Length of stay

 Dunstan et al. (1996)

a1, b2, c1, d3

Geriatric Medicine Service n = 400

development of new system (ACME)

Explained variance for Length of Stay:

Explained variance for Length of Stay (%):

Model:

Model:

Model 1: CMIX*

Model 1: 19.5 %

Model 2: Presenting Illness (PI) + Functional Status (FX)

Model 2: 19.2 %

Model 3: PI

Model 3: 13.0 %

Model 4: FX

Model 4: 14.1 %

Model + center:

Model + center:

Model 1: CMIX*

Model 1: 25.2 %

Model 2: PI + FX

Model 2: 25.0 %

Model 3: PI

Model 3: 19.6 %

Model 4: FX

Model 4: 19.3 %

Model + center + age + sex:

Model + center + age + sex:

Model 1: CMIX*

Model 1: 25.2 %

Model 2: PI + FX

Model 2: 25.0 %

Model 3: PI

Model 3: 20.1 %

Model 4: FX

Model 4: 19.4 %

*CMIX is a three-level score calculated by simple addition of the 0 and 1 scores of PI and FX.

 

 Sahadevan et al. (2004)

a2, b1, c1, d2

Acute care hospital Department of Geriatric Medicine & General Medicine Department

n = 232

DRG

Variance explained in actual Length of Stay:

Variance explained in actual Length of Stay (adjusted R2):

 

Analysis with outliers:

Analysis with outliers:

Length of stay (all subjects):

Length of stay (all subjects):

Model 1: DRG’s trimmed ALOS

Model 1: 8 %

Model 2: Functional status at discharge, total number of referrals to therapists, trimmed ALOS

Model 2: 28 %

Interdepartmental differences in Length of stay (subjects with common DRG):

Interdepartmental differences in Length of stay (subjects with common DRG):

Model 1: Department factor + DRG’s trimmed ALOS

Model 1: 23 %

Model 2: Functional profile at discharge, total number of referrals to therapists, trimmed ALOS, department factor

Model 2: 31.4 %

Analysis without outliers:

Analysis without outliers:

Length of stay (all subjects):

Length of stay (all subjects):

Model 1: DRG’s trimmed ALOS

Model 1: 23.8 %

Model 2: Overall functional profile at admission, total number of therapy referrals, trimmed ALOS

Model 2: 31.4 %

Interdepartmental differences in Length of stay (subjects with common DRG):

Interdepartmental differences in Length of stay (subjects with common DRG):

Model 1: Department factor, DRG’s trimmed ALOS

Model 1: 28.1 %

Model 2: Overall functional profile at admission, trimmed ALOS, referrals to medical social worker, department factor

Model 2: 34.5 %

 Carpenter et al. (2007)

a2, b2, c1, d2

Hospital n = 1685

HRG (equivalent to DRG)

Difference in actual Length of Stay & predicted Length of Stay:

Difference in actual Length of Stay & predicted Length of Stay (Ratio & 95 % CI)

All patients:

All patients:

Model 1: low and medium ADL score

Model 1: 1

Model 2: high ADL score

Model 2: 1.40 (1.26–1.56)

Stroke:

Stroke:

Model 1: low and medium ADL score

Model 1: 1

Model 2: high ADL score

Model 2: 1.67 (1.23–2.26)

Acute respiratory infection:

Acute respiratory infection:

a)

a)

Model 1: medium ADL score

Model 1: 1

Model 2: high ADL score

Model 2: 1.44 (1.16–1.80)

b)

b)

Model 1: low ADL score

Model 1: 1

Model 2: medium ADL score

Model 2: 1.37 (1.01–1.85)

Chronic obstructive pulmonary disease:

Chronic obstructive pulmonary disease:

Model 1: low and medium ADL score

Model 1: 1

Model 2: high ADL score

Model 2: 1.21 (1.04–1.53)

Falls:

Falls:

Model 1: low and medium ADL score

Model 1: 1

Model 2: high ADL score

Model 2: 1.68 (1.23–2.28)

* all models controlled for healthcare resource group length of stay, hospital, discharge destination, admission source and age

 Herwig et al. (2009)

a2, b2, c2, d1

University hospital, Psychiatry

n = 613

development of new system based on AMDP

Predicted variation in Length of Stay:

Predicted variation Length of Stay (%):

Model 1: AMDP Syndromes (Psychopathological Syndromes)*

Model 1: 5,9 %

Model 2: AMDP Syndromes + Age at admission + Global assessment of functioning + clinical global impressions + voluntary admission + own apartment**

Model 2: 19,8 %

*n = 998

 

**n = 613

 Warner et al. (2004)

a2, b3, c2, d1

Inpatient & Outpatient Veterans

n = 5888

ACG & DCG

Predicting inpatient, outpatient and total days of care:

Predicting inpatient, outpatient and total days of care (R2):

DCG:

DCG*:

Model 1: Age/sex + HCCs

Model 1: Inpatient days of care (IP): 0.36; Outpatient days of care (OP): 0.33; Both: 0.30

Model 2: Functionally enhanced*

Model 2: IP: 0.36; OP: 0.33; Both: 0.30

ACG:

ACG*:

Model 1: Age/sex + ADGs

Model 1: IP: 0.15; OP: 0.28; Both: 0.20

Model 2: Functionally enhanced*

Model 2: IP: 0.19; OP: 0.28; Both: 0.22

* Functionally enhanced: ACG/DCG + age, gender + self-reported functional measure

* n = 2347 for inpatient days of care and n = 5888 for outpatient days of care

Resource provision

 Phillips & Hawes (1992)

a1, b3, c2, d3

Nursing care units n = 1792

RUG-II

Explained variation in resource provision by time:

Explained variation in resource provision by time (R2):

Licensed time:

Licensed time:

Model 1: RUG-II

Model 1: 0.14

Model 2: RUG-II with cognitive variables

Model 2: 0.16

Aide time:

Aide time:

Model 1: RUG-II

Model 1: 0.39

Model 2: RUG-II with cognitive variables

Model 2: 0.39

Total time:

Total time:

Model 1: RUG-II

Model 1: 0.40

Model 2: RUG-II with cognitive variables

Model 2: 0.40

  1. ACG Adjusted Clinical Groups, ACME Admission Case-Mix System for the Elderly, ADG Adjusted Diagnostic Groups, ADL activities of daily living, ALOS average length of stay, AMDP Arbeitsgemeinschaft für Methodik und Dokumentation, CI confidence interval, DCG Diagnostic Costing Groups, DRG Diagnosis Related Groups, FX functional status, HCC Hierarchical Condition Categories, HMO health maintenance organization, HRG Healthcare Resource Groups, IP inpatient days of care, MAPE Mean Absolute Predicted Error, MCS Mental Component Score, ns not specified, OP outpatients days of care, PCS Physical Component Score, PI presenting illness, RUG-II Resource Utilization Groups Version II, VA veteran affairs
  2. aSee Table 1 study characteristics
  3. bInformation in the table is presented as stated by author
  4. cPresentation of figures of key results for each model are aligned with the presentation of results by authors of the study