Byron B. Hamilton

Performance Profiles Of The Functional Independence Measure

The functional independence measure (FIM) is used to determine the degree of disability that patients experience and the progress that they make through programs of medical rehabilitation. Rasch analysis is a statistical technique for constructing interval measures from ordinal data that was applied to derive FIM measures. The major factors that are taken into account to produce FIM measures are the relative difficulty in performance of FIM items and the ability of the persons tested. Our analyses showed the relative difficulties that patients experienced in performing items in the FIM. There were two dominant patterns of difficulty, one for motor FIM items and the other for cognitive FIM items. The patterns were consistent across impairment groups, although not identical. Of the motor items, eating and grooming were easiest whereas stair climbing, tub/shower transfers and locomotion were most difficult. Of the cognitive items, expression and comprehension were easiest and problem solving was the most difficult. The patterns of difficulty in performing FIM items are illustrated by analysis of the following impairment groups: for motor items, orthopedic conditions, stroke with left hemiparesis and spinal cord dysfunction; for cognitive items, orthopedic conditions, brain dysfunction, stroke with right hemiparesis and spinal cord dysfunction. By understanding patterns of difficulty in performing FIM items according to types of impairment and levels of function, clinicians may more precisely design treatment programs, use services and predict outcomes of medical rehabilitation.

Relationships between impairment and physical disability as measured by the functional independence measure.

This study was conducted to scale the Functional Independence Measure (FIM) with Rasch Analysis and to determine the similarity of scaled measures across impairment groups. The results show that the FIM contains two fundamental subsets of items: one measures motor and the second measures cognitive function. Rasch analysis of the Uniform Data System for Medical Rehabilitation patient sample yielded interval measures of motor and cognitive functions. The validity of the FIM was supported by the patterns of item difficulties across impairment groups. Adequate clinical precision of the FIM was demonstrated, though suggestions for improvement emerged. The frequency of misfit between patients and the performance scales varied across impairment groups, but was acceptable. The results of this project will enable clinicians and researchers to plan cost-effective treatment by providing a valid measure of disability.

A CASE-MIX CLASSIFICATION SYSTEM FOR MEDICAL REHABILITATION

Dissatisfaction with Medicares current system of paying for rehabilitation care has led to proposals for a rehabilitation prospective payment system, but first a classification system for rehabilitation patients must be created. Data for 36,980 patients admitted to and discharged from 125 rehabilitation facilities between January 1, 1990, and April 19, 1991, were provided by the Uniform Data System for Medical Rehabilitation. Classification rules were formed using clinical judgment and a recursive partitioning algorithm. The Functional Independence Measure version of the Function Related Groups (FIM-FRGs) uses four predictor variables: diagnosis leading to disability, admission scores for motor and cognitive functional status subscales as measured by the Functional Independence Measure, and patient age. The system contains 53 FRGs and explains 31.3% of the variance in the natural logarithm length of stay for patients in a validation sample. The FIM-FRG classification system is conceptually simple and stable when tested on a validation sample. The classification system contains a manageable number of groups, and may represent a solution to the problem of classifying medical rehabilitation patients for payment, facility planning, and research on the outcomes, quality, and cost of rehabilitation.

Intermodal agreement of follow-up telephone functional assessment using the functional independence measure in patients with stroke

OBJECTIVE To examine the intermodal agreement of Functional Independence Measure (FIM) ratings when obtained by two commonly used approaches: telephone interview and in-person assessment of functional performance. DESIGN A random sample of 40 persons with hemiparesis was tested by two registered nurses trained in FIM definitions and telephone interview techniques. The two assessments occurred within 5 days of each other. The raters were blind to previous assessments. The administration of assessments was alternated to minimize bias and order effects. SETTING All subjects were assessed at home, between 3 and 10 months after discharge from rehabilitation. PATIENTS The criteria for inclusion were: (1) diagnosis of cerebral vascular accident (CVA); (2) completion of a minimum of 2 weeks in an acute rehabilitation program; (3) currently living at home; (4) living within a 30-mile radius of the hospital; and (5) cognitive and verbal skills adequate to complete a telephone interview. From a population of 103 patients, 40 subjects were randomly selected, 18 women and 22 men ranging in age from 37 to 90 years. MAIN OUTCOME MEASURES The intermodal agreement between FIM ratings obtained by telephone interview and in-person assessment was examined using the intraclass correlation (ICC). FIM item scores were analyzed for agreement using the Kappa coefficient. The stability of the responses was determined by computing the coefficient of variation and plotting the data to visually examine the relationship between the two methods of administration. RESULTS Data analysis revealed that there was no statistically significant difference (p > .05) between the two methods of administration for total FIM score. The total FIM ICC was .97. ICC values for FIM subscales ranged from .85 to .98, except for social cognition. Kappa scores for noncognitive items ranged from .49 (bowel movement) to .93 (grooming). The coefficient of variation computed to examine cognitive and communication items with reduced variability indicated good stability across all items. CONCLUSION The results indicated good intermodal agreement for follow-up telephone assessment using the Functional Independence Measure. The findings were limited to persons with effective communication skills.

Measurement characteristics of the Functional Independence Measure.

Clinicians and researchers recognize the need for measures offunctional status that possess linear properties and are reliable and valid. Rasch rating scale analysis provides the means for converting raw scores from functional assessment tools to linear measures for which measurement error can be quantified. The extent to which clinicians perceive patients who are undergoing rehabilitation after stroke as similarto other patient groups was investigated using the Functional Independence Measure (FIM). Earlier work demonstrated that the first 13 items of the FIM represent a measure of motor function and that the last 5 items represent a measu re of cognitive function. The FIM was used for patients with stroke in a manner similar to that for most other impairment groups on the motor items. Patients with stroke were, however, unlike many impairment groups in their ratings on the cognitive items. Tables showing raw score to scaled measure conversions are provided for two sets of impairment groups on the motor items and three sets of impairment groups on the cognitive items. Clinicians can be confident that the measures derived from the FIM are linear across the range of the instrument and are attuned to the uniqueness of patients with stroke and other specific impairments.

Functional gain and length of stay for major rehabilitation impairment categories. Patterns revealed by function related groups.

This study evaluates the relationship of functional severity to patterns of functional gain and length of stay (LOS) for patients discharged from medical rehabilitation. It further compares differences in patterns between summed and Rasch transformed subscales of the Functional Independence Measure (FIM). Two different schemes of the FIM-Function Related Groups (FIM-FRGs) are used to define groups of patients who present with similar degrees of functional severity. The first scheme was developed using summed admission motor and cognitive FIM subscores (FIM-FRGs). The second scheme was developed by transforming these same motor and cognitive FIM subscores into logits (Logit FIM-FRGs), thus making FIM scores more equal-interval. The study included 32,494 patients who were discharged from 123 facilities that submitted data to the Uniform Data System for Medical Rehabilitation (UDSMR) and involved the separate evaluation of 18 different rehabilitation impairment categories. Motor FIM gain was calculated for each FRG in both schemes as the patients discharge motor FIM score minus the admission motor FIM score. There were four patterns of motor FIM gain and two patterns of LOS across rehabilitation impairment. The most common pattern in both schemes was linear trend, for which median gains and LOS were highest for patients in the most disabled FRGs and lowest for patients in the least disabled FRGs. Gain patterns differed across impairment and across the two schemes. The motor FIM gain distributions provide clinicians with a range of typical functional outcomes for patients admitted to medical rehabilitation. This descriptive approach provides clinicians and administrators with a simple way to compare the motor FIM gain and LOS patterns of patients teated in local facilities with broad-based norms. This sample includes about one-quarter of rehabilitation facilities nationwide, thus representing population standards for facilities participating in the UDSMR. Suggestions are made on how to use these norms most appropriately for both facility and patient comparison.

Inpatient hospital utilization among veterans with traumatic spinal cord injury.

OBJECTIVE To describe the pattern of inpatient hospital utilization, up to 15 years after injury, among a cohort of veterans with service-connected traumatic spinal cord injury (SCI). PATIENTS A cohort of 1,250 male veterans, with traumatic SCI occurring between 1970 and 1986, who visited the VA within 1 year of injury, was assembled from VA administrative files; diagnosis was verified by examining hospital discharge summaries. DESIGN Computerized record linkage among Department of Veterans Affairs (VA) administrative files was used to determine patterns of inpatient hospital utilization. MAIN OUTCOME MEASURE Pattern of inpatient admissions and length of stay (LOS). RESULTS Patients were typically white males injured in their mid-twenties. The initial VA hospitalization began approximately 6 weeks after injury and lasted 4 to 7 months, depending on injury level and completeness. Subsequent hospitalizations usually lasted approximately 10 days, but 22% of stays exceeded 1 months. Most hospitalizations took place in specialized SCI Centers. Comparing the 1980s with the 1970s, patients in the 1980s entered VA facilities sooner after injury, were more likely to visit SCI Centers, and had shorter initial stays. Rates for the incidence of rehospitalization decreased rapidly in years 2-5 after injury and declined less rapidly thereafter. Occupancy rates and proportion rehospitalized followed similar patterns. The incidence rate for persons with complete quadriplegia was approximately twice that of patients with incomplete paraplegia. Between 1970 and 1991, both the rehospitalization incidence rate and LOS decreased by approximately 20%. Only 10% of patients accounted for 46% of the total LOS. LOS during the first five years was predictive of later LOS. CONCLUSIONS The pattern of rehospitalization in VA facilities was generally consistent with that of the Model Systems. Efforts toward preventing rehospitalization should target persons with previous high utilization.

Relation of Disability Costs to Function: Spinal Cord Injury

OBJECTIVE This study evaluated the validity of the Functional Independence Measure (FIM instrument) in predicting (1) the number of minutes of daily assistance provided, (2) the cost of durable goods currently used, and (3) the number of paid helper hours provided daily to persons with spinal cord injury living in the community. DESIGN A cross-sectional study. SUBJECTS One hundred nine persons with spinal cord injury who were a median 6 years postdischarge from initial medical rehabilitation. RESULTS A significant inverse linear relationship was observed between FIM scores and the square root values of the three cost-related measures. The FIM-18 and the FIM motor scores were the best single predictors of the square root of minutes of assistance (paid and/or unpaid) per day, explaining 85% of variance. The FIM motor measure was the best single predictor of square root of cost of durable goods, explaining 29% of variance. The Self-Care, FIM motor, and FIM-18 scores equally predicted square root of hours of paid help per day, explaining 58% of variance. CONCLUSION The findings indicate FIM-related scores predict the amount of assistance needed and certain costs for persons with spinal cord injury disability.

Inpatient rehabilitation after stroke: a comparison of lengths of stay and outcomes in the Veterans Affairs and non-Veterans Affairs health care system.

Background.Patients have longer lengths of hospital stay (LOS) in VA medical centers than in the general health care system. Objective.The objective of this study was to determine whether resource use and outcome differences between VA and non-VA inpatient rehabilitation facilities remain after controlling for patient and medical care delivery differences. Design.This analysis involved 60 VA inpatient rehabilitation units and 467 non-VA rehabilitation hospitals and units. Multivariate adjusted resource use and patient outcome differences were compared across setting within patients grouped by severity of disability at admission through assignment to the Function Related Group (FRG) patient classification system. Subjects.The study included 55,438 stroke patients. Measures.Study measures were LOS, functional status at discharge, and community discharge. Results.The VA serves a higher proportion of patients who are single, separated, or divorced; are unemployed or retired as a result of disability, and are not white (P <0.0001). These traits tended to be associated with longer LOS, lower functional outcomes, and reduced rates of community discharge. After adjusting for these and other differences, depending on FRG, average LOS remained from 30% to 200% longer in the VA centers (P <0.05); average functional outcomes were significantly higher in 8 and lower in 2 FRGs (P <0.05); and community discharge rates were lower in 12 FRGs (P <0.05). Conclusions.While certain variables accounted for some of the observed differences in resource use and outcomes, differences remained after adjustment. Fewer incentives for cost containment and less support in patients’ home environments may be among the most important unmeasured determinants of VA differences.

Stroke Rehabilitation Outcome Variation in Veterans Affairs Rehabilitation Units: Accounting for Case-Mix

OBJECTIVE To assess variation in stroke outcomes and create a case-mix adjustment model for stroke rehabilitation in Veterans Affairs Medical Centers. DESIGN Observational SETTING AND PATIENTS Within Veterans Health Administration hospitals, there are 63 acute rehabilitation bedservice units that care for approximately 2,000 stroke patients annually. MAIN OUTCOME MEASURES Functional gain in FIM points, length of stay (LOS), LOS efficiency (FIM gain/LOS). RESULTS Significant variation in average patient functional gain, LOS, and LOS efficiency was observed among the 37 highest-volume rehabilitation units. Using analysis of covariance, a model was developed that adjusted functional gain and LOS (logged LOS) unit means using 10 potential covariates identified in a literature review and in pilot studies. Four and six covariates, respectively, were retained in the final models for FIM gain and LOS. The R2 for FIM gain and LOS accounted for by rehabilitation unit alone increased from .07 to .31 (FIM gain) and from .13 to .34 (logLOS) with the addition of the significant covariates to each model. CONCLUSIONS As much as 24% of the variation in two important stroke rehabilitation outcomes is attributable to largely immutable patient and system characteristics (eg, patient function on admission, age, days since stroke onset, year of discharge, marital status, and referral source). Hence, controlling for case-mix is critical for accurate comparison of unit outcomes. Further, the variation in LOS efficiency between VA rehabilitation units suggests a large potential for cost and resource utilization savings system-wide.