Evaluating the Planned Substitution of the Minimum Data Set-Post Acute Care for Use in the Rehabilitation Hospital Prospective Payment System

The Development of a Crosswalk for Functional Measures in Postacute Medicare Claims

OBJECTIVE

Although Medicare assessment files will include Standardized Patient Assessment Data Elements from 2016 forward, lack of uniformity of functional data prior to 2016 impedes longitudinal research. The purpose of this study was to create crosswalks for postacute care assessment measures and the basic mobility and daily activities scales of the Activity Measure for Post-Acute Care (AM-PAC) and to test their accuracy and validity in development and validation datasets.

METHODS

This cross-sectional study is a secondary analysis of AM-PAC, the Inpatient Rehabilitation Facility Patient Assessment Instrument, the Minimum Data Set, and the Outcome and Assessment Information Set data from 300 adults receiving rehabilitation recruited from 6 health care networks in 1 metropolitan area. Rasch analysis was used to co-calibrate items from the 3 measures onto the AM-PAC metric and to create look-up tables to create estimated AM-PAC (eAM-PAC) scores. Mean scores and correlation and agreement between actual and estimated scores were examined in the development dataset. Scores were estimated in a cohort of Medicare beneficiaries with hip, humerus and radius fractures. Correlations between eAM-PAC and Functional Independence Measure motor scores were examined. Differences in mean eAM-PAC scores were evaluated across groups of known differences (age, fracture type, dementia).

RESULTS

Strong correlations were found between actual and eAM-PAC scores in the development dataset. Moderate to strong correlations were found between the eAM-PAC basic mobility and Functional Independence Measure motor scores in the validation dataset. Differences in basic mobility scores across known groups were statistically significant and appeared to be clinically important. Differences between mean daily activities scores were statistically significant but appeared not to be clinically important.

CONCLUSION

Although further testing is warranted, the basic mobility crosswalk appears to provide valid scores for aggregate analysis of Medicare postacute care data.

IMPACT

This study reports on a method to take data from different Medicare administrative data sources and estimate scores on 1 scale. This approach was applied separately for data related to basic mobility and to daily activities. This may allow researchers to overcome challenges with using Medicare administrative data from different sources.

Tracking functional status across the spinal cord injury lifespan: linking pediatric and adult patient-reported outcome scores

OBJECTIVE

To use item response theory (IRT) methods to link scores from 2 recently developed contemporary functional outcome measures, the adult Spinal Cord Injury-Functional Index (SCI-FI) and the Pedi SCI (both the parent version and the child version).

DESIGN

Secondary data analysis of the physical functioning items of the adult SCI-FI and the Pedi SCI instruments. We used a nonequivalent group design with items common to both instruments and the Stocking-Lord method for the linking. Linking was conducted so that the adult SCI-FI and Pedi SCI scaled scores could be compared.

SETTING

Community.

PARTICIPANTS

This study included a total sample of 1558 participants. Pedi SCI items were administered to a sample of children (n=381) with SCI aged 8 to 21 years, and of parents/caregivers (n=322) of children with SCI aged 4 to 21 years. Adult SCI-FI items were administered to a sample of adults (n=855) with SCI aged 18 to 92 years.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Five scales common to both instruments were included in the analysis: Wheelchair, Daily Routine/Self-care, Daily Routine/Fine Motor, Ambulation, and General Mobility functioning.

RESULTS

Confirmatory factor analysis and exploratory factor analysis results indicated that the 5 scales are unidimensional. A graded response model was used to calibrate the items. Misfitting items were identified and removed from the item banks. Items that function differently between the adult and child samples (ie, exhibit differential item functioning) were identified and removed from the common items used for linking. Domain scores from the Pedi SCI instruments were transformed onto the adult SCI-FI metric.

CONCLUSIONS

This IRT linking allowed estimation of adult SCI-FI scale scores based on Pedi SCI scale scores and vice versa; therefore, it provides clinicians with a means of tracking long-term functional data for children with an SCI across their entire lifespan.

Underestimating physical function gains: comparing FIM motor subscale and interRAI post acute care activities of daily living scale

OBJECTIVE

To investigate the construct validity of the activities of daily living (ADLs) sections of 2 major systems developed to measure functional ability in rehabilitation settings. Health assessment systems can inform care planning as well as policy decision-making on service effectiveness. Frailty, comorbidity, and heterogeneity make it difficult to accurately measure health outcomes for older adults. Objective investigation of the value of geriatric rehabilitation services requires assessment systems that are comprehensive, reliable, valid, and sensitive to clinically relevant changes in older patients.

DESIGN

Trained health care workers assessed patients with both tools at admission and discharge. We used Rasch analysis to compare the instruments' dimensionality, item difficulty, item fit, differential item function, and number of response options.

SETTING

Musculoskeletal and geriatric rehabilitation units in 2 Ontario hospitals.

PARTICIPANTS

Older adults receiving rehabilitation (N=209; mean age ± SD, 78.5±9.3; 67% women).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

FIM and the interRAI Post Acute Care Assessment (interRAI PAC).

RESULTS

For both the FIM motor and the interRAI PAC ADLs items, the difficulty level of the items was much lower than the participant's level of ability, resulting in a large ceiling effect. Also, on both scales, less actual change in functional ability was required to move between the midlevel response options.

CONCLUSIONS

Both scales have limited ability to discriminate between subjects with higher functional ability, which indicates that they may underestimate the effectiveness of inpatient rehabilitation for this group of patients when used alone.

Linking the activity measure for post acute care and the quality of life outcomes in neurological disorders

OBJECTIVE

To use item response theory (IRT) methods to link physical functioning items in the Activity Measure for Post Acute Care (AM-PAC) and the Quality of Life Outcomes in Neurological Disorders (Neuro-QOL).

DESIGN

Secondary data analysis of the physical functioning items of AM-PAC and Neuro-QOL. We used a nonequivalent group design with 36 core items common to both instruments and a test characteristic curve transformation method for linking AM-PAC and Neuro-QOL scores. Linking was conducted so that both raw and scaled AM-PAC and Neuro-QOL scores (mean ± SD converted-logit scores, 50 ± 10) could be compared.

SETTING

AM-PAC items were administered to rehabilitation patients in post-acute care (PAC) settings. Neuro-QOL items were administered to a community sample of adults through the Internet.

PARTICIPANTS

PAC patients (N=1041) for the AM-PAC sample and community-dwelling adults (N=549) for the Neuro-QOL sample.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Mobility (N=25) and activity of daily living (ADL) items (N=11) common to both instruments were included in analysis.

RESULTS

Neuro-QOL items were linked to the AM-PAC scale by using the generalized partial credit model. Mobility and ADL subscale scores from the 2 instruments were calibrated to the AM-PAC metric.

CONCLUSIONS

An IRT-based linking method placed AM-PAC and Neuro-QOL mobility and ADL scores on a common metric. This linking allowed estimation of AM-PAC mobility and ADL subscale scores based on Neuro-QOL mobility and ADL subscale scores and vice versa. The accuracy of these results should be validated in a future sample in which participants respond to both instruments.

Outcomes and reimbursement of inpatient rehabilitation facilities and subacute rehabilitation programs for Medicare beneficiaries with hip fracture

OBJECTIVE

We sought to assess whether outcomes and reimbursement differ for Medicare beneficiaries with hip fracture when treated in an inpatient rehabilitation facility (IRF) compared with a skilled nursing facility (SNF) subacute rehabilitation program.

PARTICIPANTS

Clinical data were linked with Medicare claims for 29,793 Medicare fee-for-service beneficiaries with a recent hip fracture who completed treatment in 1996 or 1997 in rehabilitation facilities that subscribed to the Uniform Data System for Medical Rehabilitation.

OUTCOME MEASURES

We measured discharge destination, change in motor FIM rating, and Medicare Part A reimbursement.

RESULTS

For patients with moderate-to-severe and severe disabilities, case mix groups (CMGs) 704 and 705, the percentage of patients discharged to the community from IRFs was lower than for patients treated in subacute rehabilitation SNFs, after controlling for covariates. Adjusted odds ratios were 0.71 (95% confidence interval 0.55-0.92) for CMG 704 and 0.72 (95% confidence interval 0.63-0.83) for CMG 705. For patients in the 3 other CMGs, no significant differences were detected. Improvement in motor functional status was roughly equivalent for patients treated in IRFs and those treated in the subacute rehabilitation programs across all 5 CMGs, after controlling for covariates. Medicare Part A payments for IRFs were significantly higher than SNF payments across all CMGs.

CONCLUSION

SNF-based subacute rehabilitation was less costly and outcomes were in most, but not all, instances similar or better than IRF-based rehabilitation for Medicare fee-for-service beneficiaries who had a recent hip fracture.