A head-to-head comparison of the de Morton Mobility Index (DEMMI) and Elderly Mobility Scale (EMS) in an older acute medical population.

PURPOSE: To compare the clinimetric properties of the de Morton Mobility Index (DEMMI®) and the Elderly Mobility Scale (EMS). METHOD: A head-to-head comparison of the EMS and DEMMI® with 120 consecutive older acute medical patients. The DEMMI® and EMS were administered within 48 h of hospital admission and discharge. RESULTS: At admission, 6% and 15% of participants scored the lowest scale score for the DEMMI® and EMS, respectively. For the DEMMI®, 17% of participants scored within the minimal detectable change of the lowest scale score compared to 20% for the EMS at admission. At hospital discharge, DEMMI® scores were normally distributed and the EMS had a ceiling effect. Similar evidence of convergent, discriminant and known groups validity were obtained for the DEMMI® and EMS. There was no significant difference in responsiveness to change between the DEMMI® and EMS. The EMS was significantly quicker to administer compared to the DEMMI®. CONCLUSION: The DEMMI® and EMS are both valid measures of mobility for older acute medical patients. The DEMMI® has a broader scale width than the EMS with interval level measurement and therefore provides a more accurate method for measuring and monitoring changes in mobility for older acute medical patients. Implications for Rehabilitation Mobility of older acute medical patients. Hospitalised older acute medical patients are at "high risk" of mobility decline. Accurate measurement of mobility is essential for preventing and treating mobility decline. Many existing mobility measures have significant measurement limitations. The DEMMI® is a more accurate measure of mobility than the EMS in an older acute medical population.

Reliability and validity of the German translation of the de Morton Mobility Index (DEMMI) performed by physiotherapists in patients admitted to a sub-acute inpatient geriatric rehabilitation hospital.

BACKGROUND: Mobility is a key outcome in geriatric rehabilitation. The de Morton Mobility Index (DEMMI) is an internationally well-established, unidimensional measure of mobility with good psychometric properties. The aim of this study was to examine the reliability and construct validity of the German translation of the DEMMI in geriatric inpatients. METHODS: This cross-sectional study included patients admitted to a sub-acute inpatient geriatric rehabilitation hospital (reliability sample: N = 33; validity sample: N = 107). Reliability, validity, and unidimensionality were investigated. RESULTS: Inter-rater reliability between two graduate physiotherapists was excellent, with intra-class correlation coefficient of 0.94 (95% confidence interval: 0.88-0.97). The minimal detectable change with 90% confidence was 9 points. Construct validity for the DEMMI was evidenced by significant moderate to strong correlations with other measures of mobility and related constructs (Performance Oriented Mobility Assessment: rho = 0.89; Functional Ambulation Categories: rho = 0.70; six-minute walk test: rho = 0.73; gait speed: rho = 0.67; Falls Efficacy Scale International: rho = -0.68). Known-groups validity was indicated by significant DEMMI mean group differences between independent versus dependent walkers and walking aid users versus non-users. Unidimensionality of the German DEMMI translation was confirmed by Rasch analysis. CONCLUSIONS: The German translation of the DEMMI is a unidimensional instrument producing valid and reproducible measurement of mobility in an inpatient geriatric rehabilitation setting.

The development of the de morton mobility index (DEMMI) in an older acute medical population: item reduction using the Rasch model (part 1).

The DEMMI (de Morton Mobility Index) is a new and advanced instrument for measuring the mobility of all older adults across clinical settings. It overcomes practical and clinimetric limitations of existing mobility instruments. This study reports the process of item reduction using the Rasch model in the development of the DEMMI. Prior to this study, qualitative methods were employed to generate a pool of 51 items for potential inclusion in the DEMMI. The aim of this study was to reduce the item set to a unidimensional subset of items that ranged across the mobility spectrum from bed bound to high levels of independent mobility. Fifty-one physical performance mobility items were tested in a sample of older acute medical patients. A total of 215 mobility assessments were performed. Seventeen mobility items that spanned the mobility spectrum were selected for inclusion in the new instrument. The 17 item scale fitted the Rasch model. Items operated consistently across the mobility spectrum regardless of patient age, gender, cognition, primary language or time of administration during hospitalisation. Using the Rasch model, an interval level scoring system was developed with a score range of 0 to 100.

The Development of the de Morton Mobility Index (DEMMI) in an independent sample of older acute medical patients: refinement and validation using the Rasch model (part 2).

This study describes the refinement and validation of the 17-item DEMMI in an independent sample of older acute medical patients. Instrument refinement was based on Rasch analysis and input from clinicians and researchers. The refined DEMMI was tested on 106 older general medical patients and a total of 312 mobility assessments were conducted. Based on the results of this study a further 2 items were removed and the 15 item DEMMI was adopted. The Rasch measurement properties of the DEMMI were consistent with estimates obtained from the instrument development sample. No differential item functioning was identified and an interval level scoring system was established. The DEMMI is the first mobility instrument for older people to be developed, refined and validated using the Rasch model. This study confirms that the DEMMI provides clinicians and researchers with a unidimensional instrument for measuring and monitoring changes in mobility of hospitalised older acute medical patients.

A physical function test for use in the intensive care unit: validity, responsiveness, and predictive utility of the physical function ICU test (scored).

BACKGROUND: Several tests have recently been developed to measure changes in patient strength and functional outcomes in the intensive care unit (ICU). The original Physical Function ICU Test (PFIT) demonstrates reliability and sensitivity. OBJECTIVE: The aims of this study were to further develop the original PFIT, to derive an interval score (the PFIT-s), and to test the clinimetric properties of the PFIT-s. DESIGN: A nested cohort study was conducted. METHODS: One hundred forty-four and 116 participants performed the PFIT at ICU admission and discharge, respectively. Original test components were modified using principal component analysis. Rasch analysis examined the unidimensionality of the PFIT, and an interval score was derived. Correlations tested validity, and multiple regression analyses investigated predictive ability. Responsiveness was assessed using the effect size index (ESI), and the minimal clinically important difference (MCID) was calculated. RESULTS: The shoulder lift component was removed. Unidimensionality of combined admission and discharge PFIT-s scores was confirmed. The PFIT-s displayed moderate convergent validity with the Timed "Up & Go" Test (r=-.60), the Six-Minute Walk Test (r=.41), and the Medical Research Council (MRC) sum score (rho=.49). The ESI of the PFIT-s was 0.82, and the MCID was 1.5 points (interval scale range=0-10). A higher admission PFIT-s score was predictive of: an MRC score of ≥48, increased likelihood of discharge home, reduced likelihood of discharge to inpatient rehabilitation, and reduced acute care hospital length of stay. LIMITATIONS: Scoring of sit-to-stand assistance required is subjective, and cadence cutpoints used may not be generalizable. CONCLUSIONS: The PFIT-s is a safe and inexpensive test of physical function with high clinical utility. It is valid, responsive to change, and predictive of key outcomes. It is recommended that the PFIT-s be adopted to test physical function in the ICU.

An enhanced exercise and cognitive programme does not appear to reduce incident delirium in hospitalised patients: a randomised controlled trial.

OBJECTIVE: To determine if a programme of progressive resistance exercise, mobilisation and orientation, in addition to usual care, was superior to usual care alone in the prevention of incident delirium in older hospitalised patients. DESIGN: A randomised controlled trial. SETTING: The study was performed at a secondary referral hospital in Melbourne, Australia between May 2005 and December 2007. PARTICIPANTS: 648 consecutive medical inpatients aged 65 years or older who had been in hospital for less than 48 h and who did not have delirium. INTERVENTION: Participants were randomly allocated to a twice-daily programme of progressive resistance exercise tailored to individual ability, mobilisation and orientation in addition to usual care or to usual care alone. MEASUREMENTS: Delirium was measured using the Confusion Assessment Method at baseline and every 48 h until discharge. Secondary outcome measures were severity and duration of delirium, discharge destination and length of stay. RESULTS: Delirium occurred in 4.9% (95% CI 2.3% to 7.3%) of the intervention group (15/305) and in 5.9% (20/339; 95% CI 3.8% to 9.2%) of the group receiving usual care. No difference was observed between groups (χ(2); p=0.5). The intervention had no effect on delirium duration, severity, discharge destination or length of stay. CONCLUSION: A programme of progressive resistance exercise and orientation was not effective in reducing incident delirium in hospitalised elderly patients.

Validity of the de Morton Mobility Index (DEMMI) for measuring the mobility of patients with hip fracture during rehabilitation.

PURPOSE: Many patients suffer long term loss of mobility after hip fracture but there is no gold standard method for measuring mobility in this group. We aimed to validate a new mobility outcome measure, the de Morton Mobility Index (DEMMI) in a hip fracture population during inpatient rehabilitation. METHOD: The DEMMI was compared with the existing measures of activity limitation: 6 minute walk test, 6 metre walk test and Barthel Index on 109 consecutive patients admitted to rehabilitation after surgery for hip fracture. Patients were assessed by a physiotherapist at admission and discharge. Scale width, validity, minimal clinically important difference (MCID), responsiveness, and unidimensionality were investigated. RESULTS: Evidence of convergent, discriminant and known groups validity were obtained for the DEMMI. Responsiveness was similar across instruments and the MCIDs were consistent with previous reports. A floor effect was identified for the 6 metre walk test and 6 minute walk test at hospital admission. Rasch analysis identified that the DEMMI maintains its unidimensional properties in this population. CONCLUSIONS: The DEMMI has a broader scale width than existing measures of activity limitation and provides a unidimensional measure of mobility for hip fracture patients during inpatient rehabilitation.

Factors that predict discharge destination for patients in transitional care: a prospective observational cohort study.

OBJECTIVE: To investigate factors that predict discharge destination for patients making the transition from hospital to the community. METHODS: Using a prospective cohort design, 696 patients from 11 Transition Care Programs were recruited. Baseline patient and program characteristics were considered for predicting discharge destination, functional status, and patient length of stay. RESULTS: An increased physiotherapy staffing ratio in Transition Care Program was associated with an increased likelihood that a patient was discharged home, with an improved functional or mobility status, and after a shorter length of stay. The other factor that predicted discharge to home included having an Aged Care Assessment Service classification of low level care or home with a support package. An increased physiotherapy staffing level also reduced the likelihood of discharge to low level or high level care. The other factors that predicted discharge to low level care were having higher mobility status and older age; the other factor associated with increased likelihood of predicting discharge to high level care was having an Aged Care Assessment Service classification of high level care. CONCLUSIONS: Factors on admission that predicted discharge destination were program physiotherapy staffing ratios, Aged Care Assessment Service assessment, age and mobility status.

An investigation of the validity of six measures of physical function in people awaiting joint replacement surgery of the hip or knee.

OBJECTIVE: To assess and compare the validity of six physical function measures in people awaiting hip or knee joint replacement. DESIGN: Eighty-two people awaiting hip or knee replacement were assessed using six physical function measures including the WOMAC Function scale, SF-36 Physical Function scale, SF-36 Physical Component Summary scale, Patient Specific Functional Scale, 30-second chair stand test, and 50-foot timed walk. Validity was assessed using a head-to-head comparison design. RESULTS: Convergent validity was demonstrated with significant correlations between most measures (Spearman's rho 0.22 to 0.71). The Patient Specific Functional Scale had the lowest correlations with other measures of physical function. Discriminant validity was demonstrated with low correlations between mental health and physical function scores (Spearman's rho -0.12 to 0.33). Only the WOMAC Function scale, 30-second chair stand test, and 50-foot timed walk demonstrated known groups validity when scores for participants who walked with a gait aid were compared with those who did not. Standardized response means and Guyatt's responsiveness indexes indicated that the SF-36 was the least responsive measure. CONCLUSIONS: For those awaiting joint replacement surgery of the hip or knee, the current investigation found that the WOMAC Function scale, 30-second chair stand test, and 50-foot timed walk demonstrated the most evidence of validity. The Patient Specific Functional Scale might complement other measures by capturing a different aspect of physical function.

Validation of the de Morton Mobility Index (DEMMI) with older community care recipients.

AIM: To validate the de Morton Mobility Index (DEMMI) in community-dwelling older adults who require informal care. METHODS: Thirty-five consecutively recruited older adults (>65 years) living in the community who required informal care were included from Melbourne and regional Victoria, Australia. Participants were assessed using a battery of questionnaires, the Falls Risk for Older People (Community version), modified Barthel Index, Geriatric Depression Scale, the Medical Outcomes Survey Short Form 36, the Assessment of Quality of Life and the DEMMI. The DEMMI consists of 15 mobility items that are administered by therapist observation of physical performance. Each participant was assessed in their home. RESULTS: The DEMMI is without floor or ceiling effects for community-dwelling older adults who require informal care, and evidence of convergent, discriminant and known groups validity was obtained for the DEMMI. DEMMI data fitted the Rasch model and the minimal clinically important difference was 11 points. CONCLUSIONS: The DEMMI has suitable clinimetric properties for application in community-dwelling older adults who require informal care.

Reproducibility and validity of the Dutch translation of the de Morton Mobility Index (DEMMI) used by physiotherapists in older patients with knee or hip osteoarthritis.

OBJECTIVE: To examine the reproducibility, construct validity, and unidimensionality of the Dutch translation of the de Morton Mobility Index (DEMMI), a performance-based measure of mobility for older patients. DESIGN: Cross-sectional study. SETTING: Rehabilitation center (reproducibility study) and hospital (validity study). PARTICIPANTS: Patients (N=28; age >65y) after orthopedic surgery (reproducibility study) and patients (N=219; age >65y) waiting for total hip or total knee arthroplasty (validity study). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Not applicable. RESULTS: The intraclass correlation coefficient for interrater reliability was high (.85; 95% confidence interval, 71-.93), and minimal detectable change with 90% confidence was 7 on the 100-point DEMMI scale. Rasch analysis identified that the Dutch translation of the DEMMI is a unidimensional measure of mobility in this population. DEMMI scores showed high correlations with scores on other performance-based measures of mobility (Timed Up and Go test, Spearman r=-.73; Chair Rise Time, r=-.69; walking test, r=.74). A lower correlation of .44 was identified with the self-report measure Western Ontario and McMaster Universities Osteoarthritis Index. CONCLUSIONS: The Dutch translation of the DEMMI is a reproducible and valid performance-based measure for assessing mobility in older patients with knee or hip osteoarthritis.

The de Morton Mobility Index (DEMMI) provides a valid method for measuring and monitoring the mobility of patients making the transition from hospital to the community: an observational study.

QUESTION: Is the de Morton Mobility Index (DEMMI) valid for measuring the mobility of patients making the transition from hospital to the community? DESIGN: Observational cohort study. PARTICIPANTS: 696 consecutive patients admitted to 11 Transition Care Programs for multidisciplinary care in Victoria and Tasmania during a 6-month period. The DEMMI and Modified Barthel Index were administered within 5 working days of admission and discharge from the Transition Care Program. OUTCOME MEASURES: The DEMMI and Modified Barthel Index. RESULTS: Neither the DEMMI nor the Modified Barthel Index had a floor or ceiling effect. Similar evidence of convergent, discriminant and known-groups validity were obtained for each instrument. The DEMMI was significantly more responsive to change than the Modified Barthel Index using criterion- and distribution-based methods. The minimum clinically important difference estimates represented similar proportions of the scale width for the DEMMI and Modified Barthel Index and were similar using criterion- and distribution-based estimates. Rasch analysis identified the DEMMI as essentially unidimensional in a Transition Care Program cohort and therefore can be applied to obtain interval level measurement. Rasch analysis demonstrated that the DEMMI was administered similarly by physiotherapists and allied health assistants under the direction of a physiotherapist. CONCLUSION: The DEMMI and Modified Barthel Index are both valid measures of activity limitation for Transition Care Program patients. The DEMMI has a broader scale width, provides interval level measurement, and is significantly more responsive to change than the Modified Barthel Index for measuring the mobility of Transition Care Program patients.

Unidimensionality of the Elderly Mobility Scale in older acute medical patients: different methods, different answers.

OBJECTIVE: To investigate the unidimensionality of the Elderly Mobility Scale (EMS) in an older acute medical population. STUDY DESIGN: EMS data were collected within 48 hours of hospital admission and discharge, respectively, from consecutive older acute medical patients. Rasch and factor analysis of EMS data were conducted. SETTING: Acute tertiary hospital, South Australia. RESULTS: Factor analysis identified a two-factor solution for both admission and discharge EMS data. At hospital admission (n=120), EMS data fitted the Rasch model (χ(2)=18.31, P=0.19, df=14). One item, the timed walk test, had a high positive fit residual (+3.93). At hospital discharge (n=105), EMS data did not fit the Rasch model (χ(2)=25.66, P=0.03, df=14). Item and person scores were not well matched because of a ceiling effect in discharge EMS scores. The functional reach item showed some misfit to the Rasch model and the gait item had a disordered threshold. After rescoring this disordered threshold, discharge EMS data fitted the Rasch model. CONCLUSION: Conflicting results were identified using a classical test theory and item response theory approach. Although the EMS fitted the Rasch model, an unacceptable ceiling effect at hospital discharge limits the validity of the EMS for measuring and monitoring the mobility of older acute medical patients in the hospital setting.

Clinimetric properties of the de Morton Mobility Index in healthy, community-dwelling older adults.

OBJECTIVE: To investigate the clinimetric properties of the de Morton Mobility Index (DEMMI) in healthy, community-dwelling older adults. DESIGN: Cohort study. SETTING: Retirement village and Returned and Services League (RSL) club in Melbourne, Australia. PARTICIPANTS: All participants were 65 years or older, healthy, and living within the community. The validation study included participants recruited from a retirement village (n=61), and the reliability studies included participants recruited from an RSL club and a subset of participants from the retirement village. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Mobility was assessed using the DEMMI. The percentage of participants who scored the highest and lowest possible score on the DEMMI was calculated to determine whether a floor or ceiling effect occurred. The minimal clinically important difference (MCID) was estimated using a distribution-based method. Reliability was assessed independently and concurrently using the minimal detectable change at 90% confidence (MDC90). RESULTS: Evidence of convergent and discriminant validity was obtained for the DEMMI by examining correlations with measures of related constructs, the Lower Extremity Functional Scale (r=.69) and Quality of Life Scale scores (r=.28), respectively. Participants who ambulated without a gait aid (82.62±10.63) had significantly higher (P<.0) DEMMI scores than those who ambulated with an aid (64.1±12.40), providing evidence of known groups validity. No floor or ceiling effect was identified. The MCID was 7 points. The MDC90 was 13 (95% CI, 8.76-17.05) points on the 100-point scale. CONCLUSION: DEMMI scores in healthy, community-dwelling older adults are both valid and reliable.

Reliability of the de Morton Mobility Index (DEMMI) in an older acute medical population.

BACKGROUND: The de Morton Mobility Index (DEMMI) is an instrument that accurately measures the mobility of older people across clinical settings. PURPOSE: To report the multiple reliability studies conducted during the development and validation of the DEMMI. METHODS: Intra-rater and inter-rater reliability studies were conducted for the DEMMI in two independent samples (development and validation samples) of older acute medical patients (aged 65 years or older). Inter-rater reliability studies were conducted between the test developer (a physiotherapist) and another experienced physiotherapist. Order of assessor administration was randomized by a coin toss. Patients who were fatigued after the first assessment were excluded from the inter-rater reliability study. Intra-rater reliability studies included participants with 'unchanged' mobility status between hospital admission and discharge. Scale reliability estimates were expressed as the minimal detectable change with 90% confidence (MDC90 ). Item reliability was calculated using Kappa statistics and absolute percentage agreement. RESULTS: The MDC90 for the DEMMI development sample was 9.51 points (95% confidence interval [95% CI], 5.04-13.32; n=21) and 7.84 (95% CI, 4.34-11.65; n=16) on the 100-point interval DEMMI scale for the inter-rater and intra-rater reliability studies, respectively. Similar estimates were obtained for the DEMMI validation samples of 8.90 (95% CI, 6.34-12.69; n=35) and 13.28 points (95% CI, 8.08-20.87; n=19). Items were not excluded from the DEMMI based on the results of item reliability. CONCLUSION: Reliability estimates for the DEMMI were consistent across independent samples of older acute medical patients using different reliability study methodology. Error represents approximately 9% of the DEMMI scale width.

Application of Rasch analysis in health care is increasing and is applied for variable reasons in mobility instruments.

OBJECTIVE: To identify the frequency of Rasch analysis use in health instrument development or refinement and the characteristics of Rasch application in mobility scales. STUDY DESIGN AND SETTING: The entire databases of Medline, CINAHL, PEDro, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews were searched until January 2009. Articles that reported the development or refinement of health instruments using Rasch analysis were included. Of the 234 articles that met inclusion, 10 were categorized as "mobility" instruments. Data were extracted relating to each instrument and the use of Rasch analysis in the development or refinement of the instruments. RESULTS: The number of articles reporting the use of Rasch analysis of health instruments is increasing, from 1 article in 1987 to 48 articles in 2007. Of the 10 mobility instruments examined, the primary reason Rasch was used varied. Reasons included assessing instrument unidimensionality, differential item functioning, rating categories, item hierarchy, and redundant items. CONCLUSION: The application of Rasch analysis in health instrument development has markedly increased in recent years. However, few mobility instruments have been developed or refined using Rasch analysis. The reasons that the Rasch model was used varied across mobility instruments.

Validity, responsiveness and the minimal clinically important difference for the de Morton Mobility Index (DEMMI) in an older acute medical population.

BACKGROUND: The de Morton Mobility Index (DEMMI) is a new mobility instrument that overcomes the limitations of existing instruments. It is the first mobility instrument that accurately measures the mobility of all older adults. The aim of this study was to provide a detailed report of investigations of the validity, responsiveness to change and minimal clinically important difference (MCID) of the DEMMI during its development in an older acute medical population. METHODS: This study was conducted using a head to head comparison design in two independent samples of older acute medical patients (development sample, n = 86; validation sample, n = 106). Consecutive patients (≥ 65 years) were assessed using the DEMMI, Barthel Index (BI) and Hierarchical Assessment of Balance and Mobility (HABAM) within 48 hours of hospital admission and discharge. Convergent and discriminant validity were investigated using Spearman's rho and known groups validity was investigated using a independent t test to compare DEMMI scores for patients who were discharged to home compared to inpatient rehabilitation. Criterion and distribution based methods were employed for estimating instrument responsiveness to change and the MCID. RESULTS: Significant moderate to high correlations were identified between DEMMI and BI scores (r = 0.76 and r = 0.68) and DEMMI and HABAM scores (r = 0.91 and r = 0.92) in both samples. In both samples, DEMMI scores for patients who were discharged to home were significantly higher than for patients discharged to inpatient rehabilitation and provided evidence of known groups validity. Patients who were discharged to inpatient rehabilitation (n = 8) had a mean DEMMI score of 50.75 (sd = 11.29) at acute hospital discharge compared to patients who were discharged to home (n = 70) with a mean DEMMI score of 62.14 (sd = 18.41). MCID estimates were similar across samples using distribution and criterion based methods. The MCID for the DEMMI was 10 points on the 100 point interval scale. The DEMMI was significantly more responsive to change than the BI using criterion and distribution based methods in the validation sample. CONCLUSION: This study has validated the DEMMI in two independent samples of older acute medical patients. Estimates of its responsiveness and MCID have also been established. This study confirms that the DEMMI overcomes the limitations of the BI and HABAM and provides an advanced method for objectively assessing mobility for older acute medical patients.

Validity and reliability of the de Morton Mobility Index in the subacute hospital setting in a geriatric evaluation and management population.

OBJECTIVE: To investigate the clinimetric properties of the de Morton Mobility Index (DEMMI) in a Geriatric Evaluation and Management (GEM) population. DESIGN: A longitudinal validation study (n = 100) and inter-rater reliability study (n = 29) in a GEM population. PATIENTS: Consecutive patients admitted to a GEM rehabilitation ward were eligible for inclusion. METHODS: At hospital admission and discharge, a physical therapist assessed patients with physical performance instruments that included the 6-metre walk test, step test, Clinical Test of Sensory Organization and Balance, Timed Up and Go test, 6-minute walk test and the DEMMI. Consecutively eligible patients were included in an inter-rater reliability study between physical therapists. RESULTS: DEMMI admission scores were normally distributed (mean 30.2, standard deviation 16.7) and other activity limitation instruments had either a floor or a ceiling effect. Evidence of convergent, discriminant and known groups validity for the DEMMI were obtained. The minimal detectable change with 90% confidence was 10.5 (95% confidence interval 6.1-17.9) points and the minimally clinically important difference was 8.4 points on the 100-point interval DEMMI scale. CONCLUSION: The DEMMI provides clinicians with an accurate and valid method of measuring mobility for geriatric patients in the subacute hospital setting.

The PEDro scale is a valid measure of the methodological quality of clinical trials: a demographic study.

QUESTIONS: Does the PEDro scale measure only one construct ie, the methodological quality of clinical trials? What is the hierarchy of items of the PEDro scale from least to most adhered to? Is there any effect of year of publication of trials on item adherence? Are PEDro scale ordinal scores equivalent to interval data? DESIGN: Rasch analysis of two independent samples of 100 clinical trials from the PEDro database scored using the PEDro scale. RESULTS: Both samples of PEDro data showed fit to the Rasch model with no item misfit. The PEDro scale item hierarchy was the same in both samples, ranging from the most adhered to item random allocation, to the least adhered to item therapist blinding. There was no differential item functioning by year of publication. Original PEDro ordinal scores were highly correlated with transformed PEDro interval scores (r = 0.99). CONCLUSION: The PEDro scale is a valid measure of the methodological quality of clinical trials. It is valid to sum PEDro scale item scores to obtain a total score that can be treated as interval level measurement and subjected to parametric statistical analysis.

The de Morton Mobility Index (DEMMI): an essential health index for an ageing world.

BACKGROUND: Existing instruments for measuring mobility are inadequate for accurately assessing older people across the broad spectrum of abilities. Like other indices that monitor critical aspects of health such as blood pressure tests, a mobility test for all older acute medical patients provides essential health data. We have developed and validated an instrument that captures essential information about the mobility status of older acute medical patients. METHODS: Items suitable for a new mobility instrument were generated from existing scales, patient interviews and focus groups with experts. 51 items were pilot tested on older acute medical inpatients. An interval-level unidimensional mobility measure was constructed using Rasch analysis. The final item set required minimal equipment and was quick and simple to administer. The de Morton Mobility Index (DEMMI) was validated on an independent sample of older acute medical inpatients and its clinimetric properties confirmed. RESULTS: The DEMMI is a 15 item unidimensional measure of mobility. Reliability (MDC(90)), validity and the minimally clinically important difference (MCID) of the DEMMI were consistent across independent samples. The MDC(90) and MCID were 9 and 10 points respectively (on the 100 point Rasch converted interval DEMMI scale). CONCLUSION: The DEMMI provides clinicians and researchers with a valid interval-level method for accurately measuring and monitoring mobility levels of older acute medical patients. DEMMI validation studies are underway in other clinical settings and in the community. Given the ageing population and the importance of mobility for health and community participation, there has never been a greater need for this instrument.