Assessment and Evaluation of a Crosswalk between the Functional Independence Measure and the Continuity Assessment Record and Evaluation by DAVID MELLICK BS, University of Northern Colorado MA, University of Northern Arizona A dissertation submitted to the Faculty of the Graduate School of the University of Colorado in partial fulfillment of the requirements for the degree of Doctor of Philosophy Clinical Sciences Program 2020 This dissertation for the Doctor of Philosophy degree by David Mellick has been approved for the Clinical Sciences Program by Heather Haugen, PhD Chair Cynthia Harrison-Felix, PhD Research Mentor Gale Whiteneck, PhD Jessica M. Ketchum, PhD David Weitzenkamp, PhD Date: Tuesday, August 4, 2020 ii Assessment and Evaluation of a Crosswalk between the Functional Independence Measure and the Continuity Assessment Record and Evaluation Dissertation directed by Associate Professor Heather Haugen. Abstract Background: Assessment of functional outcome is a major initiative for facilities engaging in post-acute care. Unfortunately across time, the various types of post-acute care facilities had developed measures to assess function independently of each other, making for comparisons of patients across facilities difficult. To rectify this difference, in 2005 the Centers for Medicare and Medicaid Services developed a comprehensive measure that all facilities were to use to assess function called the Continuity Assessment Record and Evaluation (CARE). However because of the change in instruments, comparisons between the previous measures and the CARE necessitate a need for a crosswalk so that scores can be compared. This study focused on the creation and evaluation of a crosswalk between the motor subscale of the Functional Independence Measure (FIM) which had been used to assess function in inpatient rehabilitation facilities and the newer CARE tool. Methods: An existing dataset of 982 persons who had sustained a moderate to severe traumatic brain injury and were assessed using both FIM and CARE at inpatient rehabilitation admission and discharge was utilized to create three crosswalks using various methodology (expert opinion, equipercentile and Rasch). The dataset was split into a training and validation dataset. Each crosswalk was evaluated using several criteria including, reduction in uncertainty, iii percent of each crosswalked score falling within a ½ standard deviation (SD) of the reference measure, population invariance, comparison of statistical moments and effect size. Results: Using the training dataset the expert opinion crosswalk met all of the criteria except for the direction of population invariance within the race category. The equipercentile methodology satisfied all of the evaluation criteria, and the Rasch model met all of the criteria except for a difference in directionality in the skewness of the distributions as well as not meeting the targeted 80% of scores falling within ½ SD of the reference assessment. These results differed from the validation sample for the population invariance criteria, in which the age categories were in opposite directions and had observed differences between standardized mean difference for age that exceeded the threshold of 0.08 for both the equipercentile and Rasch crosswalks. Conclusions and Significance: All three crosswalk methods produced acceptable criteria for use. Therefore motor/physical functional outcome can be compared between cohorts having been assessed using different measures. The results indicate that for researchers wanting to compare cohorts that have been assessed using different instruments, any of the crosswalks could be utilized. iv Table of Contents CHAPTER I. INTRODUCTION .......................................................................................... 1 Overview.................................................................................................................... 1 Pathways of Care ................................................................................................... 1 How is Function Measured in Post-Acute Care Settings? ..................................... 3 Continuity Assessment Report and Evaluation ................................................... 10 Linking Scores ...................................................................................................... 11 Specific Aims ............................................................................................................ 13 Significance .............................................................................................................. 14 Summary ................................................................................................................. 15 CHAPTER II. Review of the Literature ......................................................................... 17 Introduction ............................................................................................................. 17 Literature Search Methods ..................................................................................... 17 Review of the Literature .......................................................................................... 18 FIM ....................................................................................................................... 18 CARE ..................................................................................................................... 20 Measurement Linking .......................................................................................... 26 Criteria for Linking ............................................................................................... 32 Linking Functional Outcomes .............................................................................. 35 Summary of Gaps in the Literature ......................................................................... 40 v CHAPTER III. METHODS .............................................................................................. 42 Research Design and Data Collection ...................................................................... 42 The Traumatic Brain Injury Model Systems National Database .......................... 42 Study Participants ................................................................................................ 44 Variables Collected .............................................................................................. 45 Analysis Plan ............................................................................................................ 48 Missing Data ........................................................................................................ 49 Analysis Plan for Research Aim 1 ......................................................................... 49 Analysis Plan for Research Aim 2 ......................................................................... 52 Validation Sample ................................................................................................ 56 CHAPTER IV. RESULTS OF ANALYSIS ........................................................................... 57 Sample Demographics ......................................................................................... 57 Sample Functional Outcome Measure Scores ..................................................... 59 Missing Data ........................................................................................................ 61 Expert Opinion ..................................................................................................... 62 Equipercentile ...................................................................................................... 68 Rasch .................................................................................................................... 82 CHAPTER V. CONCLUSION ....................................................................................... 103 Study Limitations ............................................................................................... 108 Summary ............................................................................................................... 110 CHAPTER VI. BIBLIOGRAPHY ..................................................................................... 111 vi List of Tables Table I-1: Differences in Post-Acute Care Assessments ........................................................... 6 Table I-2: Differences in Functional Measure Items ................................................................. 7 Table II-1: Justification for CARE tool core items .................................................................... 23 Table III-1: Inclusion criteria for TBIMS NDB .......................................................................... 44 Table III-2: Study Dataset Variables ........................................................................................ 45 Table III-3: Scoring Codes for the FIM-M and CARE ............................................................... 48 Table IV-1: Categorization of Severity of TBI .......................................................................... 58 Table IV-2: Demographics of the samples .............................................................................. 59 Table IV-3: Functional Outcome Measure Scores .................................................................. 60 Table IV-4: Expert Opinion FIM-M and CARE Item Conversion Scores ................................... 62 Table IV-5: Correlations