Introduction
Inpatient rehabilitation facilities utilize standardized assessments to measure patient progress and outcomes. The Centers for Medicare and Medicaid Services Inpatient Rehabilitation Facility Patient Assessment Instrument (CMS-IRF PAI) Version 1.4 includes Section GG, designed to evaluate self-care and mobility. This study aimed to determine the reliability of Section GG by comparing it with the well-established Functional Independence Measure (FIM), specifically the motor subscale (FIMm) and cognitive subscale (FIMc). Understanding the reliability of tools like Section GG is crucial for accurate patient care and outcome prediction in rehabilitation settings.
Study Design and Methods
This retrospective cohort study was conducted at a single inpatient rehabilitation facility. Researchers analyzed data from 1296 patients admitted for stroke rehabilitation between October 2016 and October 2019. The study compared patient scores on Sections GG (Self-Care and Mobility), B (Hearing, Speech, and Vision), and C (Cognitive Patterns) of the CMS-IRF PAI with their corresponding FIMm and FIMc scores. Spearman’s and Bland-Altman analyses were used to assess the relationships and agreements between these measures.
Key Findings on Section GG and FIM
The analysis revealed a strong correlation between Section GG and FIMm scores, both at admission and discharge (ρ=0.919 and ρ=0.929, P<.001 respectively). This indicates that Section GG effectively measures similar aspects of motor function as the FIMm. However, the study also found that Section GG exhibited more pronounced ceiling effects at discharge (8.6%) compared to FIMm, suggesting it may be less sensitive in detecting improvements at higher functional levels. Bland-Altman analysis indicated a consistent bias towards higher scores with Section GG compared to FIMm at both admission and discharge, as well as for functional gains. Notably, gains in self-care items were proportionally smaller in Section GG compared to FIMm, while walking and stairs showed a bias towards greater gains in Section GG.
Cognitive Assessment Comparison: Section B+C Scale
To assess cognitive function, researchers created a combined scale (B+C scale) from Section B and C of the CMS-IRF PAI. This scale demonstrated good internal validity (Cronbach’s alpha=0.868) and a significant correlation with FIMc (ρ=0.745). Despite the correlation, the B+C scale rated patients at a higher cognitive level than FIMc and showed a considerably larger ceiling effect at admission (20.4% vs 0.6%).
Conclusion and Implications for Rehabilitation
The study concluded that while Section GG and the B+C scale are correlated with FIMm and FIMc subscales respectively, they tend to provide higher ratings of patient ability. The observed ceiling effects, particularly in Section GG and the B+C scale, might limit their ability to differentiate patients at higher levels of functional independence or cognitive function. Further research is warranted to evaluate the clinical acceptability of Section GG total scores as a reliable outcome measure and predictor of long-term outcomes in inpatient rehabilitation. These findings highlight the importance of understanding the specific properties of assessment tools like Section GG to ensure accurate and effective patient care.
