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: | Model’s 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 |