The Academic Medical Center Linear Disability Score (ALDS) item bank: item response theory analysis in a mixed patient population

BACKGROUND: Currently, there is a lot of interest in the flexible framework offered by item banks for measuring patient relevant outcomes. However, there are few item banks, which have been developed to quantify functional status, as expressed by the ability to perform activities of daily life. This paper examines the measurement properties of the Academic Medical Center linear disability score item bank in a mixed population. METHODS: This paper uses item response theory to analyse data on 115 of 170 items from a total of 1002 respondents. These were: 551 (55%) residents of supported housing, residential care or nursing homes; 235 (23%) patients with chronic pain; 127 (13%) inpatients on a neurology ward following a stroke; and 89 (9%) patients suffering from Parkinson's disease. RESULTS: Of the 170 items, 115 were judged to be clinically relevant. Of these 115 items, 77 were retained in the item bank following the item response theory analysis. Of the 38 items that were excluded from the item bank, 24 had either been presented to fewer than 200 respondents or had fewer than 10% or more than 90% of responses in the category 'can carry out'. A further 11 items had different measurement properties for younger and older or for male and female respondents. Finally, 3 items were excluded because the item response theory model did not fit the data. CONCLUSION: The Academic Medical Center linear disability score item bank has promising measurement characteristics for the mixed patient population described in this paper. Further studies will be needed to examine the measurement properties of the item bank in other populations

The relationship between self-reported borderline personality features and prospective illness course in bipolar disorder

Abstract Background Although bipolar disorder (BD) and borderline personality disorder (BPD) share clinical characteristics and frequently co-occur, their interrelationship is controversial. Especially, the differentiation of rapid cycling BD and BPD can be troublesome. This study investigates the relationship between borderline personality features (BPF) and prospective illness course in patients with BD, and explores the effects of current mood state on self-reported BPF profiles. Methods The study included 375 patients who participated in the former Stanley Foundation Bipolar Network. All patients met DSM-IV criteria for bipolar-I disorder (n = 294), bipolar-II disorder (n = 72) or bipolar disorder NOS (n = 9). BPF were assessed with the self-rated Personality Diagnostic Questionnaire. Illness course was based on 1-year clinician rated prospective daily mood ratings with the life chart methodology. Regression analyses were used to estimate the relationships among these variables. Results Although correlations were weak, results showed that having more BPF at baseline is associated with a higher episode frequency during subsequent 1-year follow-up. Of the nine BPF, affective instability, impulsivity, and self-mutilation/suicidality showed a relationship to full-duration as well as brief episode frequency. In contrast all other BPF were not related to episode frequency. Conclusions Having more BPF was associated with an unfavorable illness course of BD. Affective instability, impulsivity, and self-mutilation/suicidality are associated with both rapid cycling BD and BPD. Still, many core features of BPD show no relationship to rapid cycling BD and can help in the differential diagnosis

What should be defined as good outcome in stroke trials; a modified Rankin score of 0-1 or 0-2?

Background and purpose Good outcome in stroke trials has been defined as a modified Rankin scale (mRs) score of 0-1 or 0-2. The aim of this study was to investigate the clinical meaning of these two dichotomies. Methods We studied 152 patients six months post stroke using the mRs and a new disability measure the AMC Linear Disability Scale (ALDS) item bank. Descriptive statistics were used to show the ALDS scores by the levels of the mRs. To investigate the clinical meaning of the different definitions of good outcome, the mean probability to perform activities of daily life (ADL) of all mRs grades and these two dichotomies was calculated. Results The ability to perform difficult ALDS items declined gradually with increasing mRs grade. When favourable outcome is defined as mRs 0-1, 15% of the cohort has a good outcome; of these patients 84 % were likely to perform outdoor activities. If good outcome is defined as mRs 0-2, the percentage of patients with good outcome increased to 37%, whereas 66% of these patients were likely to perform outdoor activities. Conclusion If good outcome is defined as the ability to perform outdoor activities mRs 0-1 should be chosen. If complex ADL are considered as good outcome mRs 0-2 is the outcome measure of choice. Independent of which outcome measure is chosen, the treatment effect in clinical trials must be large before good outcome is achieved. Therefore, it is likely that clinically important treatment effects can be missed in clinical trials with both these mRs endpoint

The use of an item response theory-based disability item bank across diseases: accounting for differential item functioning

Objective: There is not a single universally accepted activity of daily living (ADL) instrument available to compare disability assessments across different patient groups. We developed a generic item bank of ADL items using item response theory, the Academic Medical Center Linear Disability Scale (ALDS). When comparing outcomes of the ALDS between patients groups, item characteristics of the ALDS should be comparable across groups. The aim of the study was to assess the differential item functioning (DIF) in a group of patients with various disorders to investigate the comparability across these groups. Study Design and Setting: Cross-sectional, multicenter study including 1,283 in- and outpatients with a variety of disorders and disability levels. The sample was divided in two groups: (1) mainly neurological patients (n = 497; vascular medicine, Parkinson's disease and neuromuscular disorders) and (2) patients from internal medicine (n = 786; pulmonary diseases, chronic pain, rheumatoid arthritis, and geriatric patients). Results: Eighteen of 72 ALDS items showed statistically significant DIF (P <0.01). However, the DIF could effectively be modeled by the introduction of disease-specific parameters. Conclusion: In the subgroups studied, DIF could be modeled in such a way that the ensemble of the items comprised a scale applicable in both groups. (C) 2010 Elsevier Inc. All rights reserve

Meta-analysis for the ES() between impairment, disability, and health-related quality of life and the subgroup analyses

<p><b>Copyright information:</b></p><p>Taken from "The impact of disease-related impairments on disability and health-related quality of life: a systematic review"</p><p>http://www.biomedcentral.com/1471-2288/7/24</p><p>BMC Medical Research Methodology 2007;7():24-24.</p><p>Published online 19 Jun 2007</p><p>PMCID:PMC1914351.</p><p></p

The impact of disease-related impairments on disability and health-related quality of life: a systematic review-1

<p><b>Copyright information:</b></p><p>Taken from "The impact of disease-related impairments on disability and health-related quality of life: a systematic review"</p><p>http://www.biomedcentral.com/1471-2288/7/24</p><p>BMC Medical Research Methodology 2007;7():24-24.</p><p>Published online 19 Jun 2007</p><p>PMCID:PMC1914351.</p><p></p>the standard normal distribution (X as) while the other is the distribution one wishes to compare it against (here the Y as is defined as ES()/√). The deviations from linearity indicate deviations in normality. Publication bias will tend to leave strange gaps in the plot or lead to strange curves

The impact of disease-related impairments on disability and health-related quality of life: a systematic review-2

<p><b>Copyright information:</b></p><p>Taken from "The impact of disease-related impairments on disability and health-related quality of life: a systematic review"</p><p>http://www.biomedcentral.com/1471-2288/7/24</p><p>BMC Medical Research Methodology 2007;7():24-24.</p><p>Published online 19 Jun 2007</p><p>PMCID:PMC1914351.</p><p></p>the standard normal distribution (X as) while the other is the distribution one wishes to compare it against (here the Y as is defined as ES()/√). The deviations from linearity indicate deviations in normality. Publication bias will tend to leave strange gaps in the plot or lead to strange curves

The Academic Medical Center Linear Disability Score item bank: psychometric properties of a new generic disability measure in rheumatoid arthritis

OBJECTIVE: To determine the psychometric properties of the Academic Medical Center (AMC) Linear Disability Scale (ALDS) item bank in a population of patients with rheumatoid arthritis (RA). METHODS: 129 patients with RA completed the ALDS and Health Assessment Questionnaire Disability Index (HAQ-DI) at baseline, and after 8 and 16 weeks of anti-tumor necrosis factor-alpha treatment. Disease activity assessments at these timepoints included serum levels of C-reactive protein, Disease Activity Score 28, morning stiffness, and visual analog scales for global disease activity and fatigue. RESULTS: Reliability of the ALDS was excellent (homogeneity, Cronbach's alpha = 0.95; test-retest, intraclass correlation coefficient = 0.93). The ALDS results at baseline were strongly correlated with the HAQ-DI (r = -0.75). With regard to known group validity, both instruments discriminated between higher and lower disease activity (ALDS, p < 0.0001; HAQ-DI, p = 0.002) and between non-, moderate, and good responders (ALDS, p = 0.002; HAQ-DI, p < 0.0001), indicating that both instruments differentiate between groups. The ALDS was moderately to highly responsive to changes between baseline and after 8 weeks and 16 weeks of treatment (standardized response mean, range = 0.71-1.19). No substantial floor or ceiling effects were found. CONCLUSION: Our results show that the ALDS is a promising new instrument, with at least equivalent psychometric properties compared to the HAQ-DI. Advantages of the ALDS item bank are its linear structure and an item bank that can be adapted depending on the ability level of the patien