Concurrent Validation of the Inpatient Rehabilitation Facility Patient Assessment Instrument Version 1.4; Sections GG, B, and C

Abstract

ObjectiveTo validate Sections GG (Self-Care and Mobility Assessment), B (Hearing, Speech, and Vision), and C (Cognitive Patterns) of the Centers for Medicare and Medicaid Services Inpatient Rehabilitation Facility Patient Assessment Instrument (CMS-IRF PAI) Version 1.4 in comparison with Functional Independence Measure (FIM) motor subscale (FIMm) and cognitive subscale (FIMc). DesignRetrospective cohort. SettingSingle inpatient rehabilitation facility. ParticipantsCohort of 1296 patients admitted for rehabilitation after stroke, between October 1, 2016, and October 1, 2019. InterventionsNot applicable. Main Outcome MeasuresSections GG, B, and C scores were compared with FIMm and FIMc using Spearman's and Bland-Altman Analyses. ResultsSections GG and FIMm were highly correlated on admission (ρ=0.919, P<.001) and discharge (ρ=0.929, P<.001). Ceiling effects at discharge were more pronounced for Section GG (8.6%). Bland-Altman analyses revealed a bias toward higher scores on Section GG vs FIMm on admission (Bias=2.3%, P<.001), and discharge (Bias=6.2%, P<.001). Section GG showed bias toward greater gains in function (Bias=3.9%, P<.001), particularly in walking and stairs (bias=3.71%, P<.001). Comparable self-care items accounted for a smaller percentage of the Section GG gains compared with FIMm (bias=-7.5%, P<.001).The internal validity of a scale consisting of Section B and C (B+C scale) was good, (Cronbach's alpha=0.868) and was highly correlated with FIMc (ρ=0.745), but rated patients at a higher level of cognition (bias=20.0%, P<.001) and had a greater ceiling effect (20.4%) on admission compared with the FIMc (0.6%). ConclusionThe B+C scale and Section GG were correlated with FIMc and FIMm subscales but biased toward higher ratings of ability. Ceiling effects may limit discrimination at higher level of cognition/functional independence. The clinical acceptability of Section GG total scores as an outcome measure and predictor of long-term outcomes requires further study.