Setting up a cohort study of functioning: From classification to measurement

OBJECTIVE: Cohort studies are an appropriate method for the collection of population-based longitudinal data to track people's health and functioning over time. However, describing and understanding functioning in its complexity with all its determinants is one of the biggest challenges faced by clinicians and researchers.DESIGN: This paper focuses on the development of a cohort study on functioning, outlining the relevant steps and related methods, and illustrating these with reference to the Swiss Spinal Cord Injury Cohort Study (SwiSCI).METHODS AND RESULTS: In setting up a cohort study the initial step is to specify which variables are to be included, i.e. what to assess. The International Classification of Functioning, Disability and Health (ICF) is valuable in this process. The second step is to identify how to assess the specified ICF categories. Existing instruments and assessments can then be linked to the ICF.CONCLUSION: The methods outlined here enable the development of a cohort study to be based on a comprehensive perspective of health, operationalized through functioning as conceptualized and classified in the ICF, yet to remain efficient and feasible to administer.<br/

Establishing score equivalence of the Functional Independence Measure motor scale and the Barthel Index, utilising the International Classification of Functioning, Disability and Health and Rasch measurement theory

Introduction: Two widely used outcome measures to assess functioning in neurological rehabilitation are the Functional Independence Measure (FIM™) and the Barthel Index. The current study aims to establish the equivalence of the total score of the FIM™ motor scale and the Barthel Index through the application of the International Classification of Functioning, Disability and Health, and Rasch measurement theory. Methods: Secondary analysis of a large sample of patients with stroke, spinal cord injury, and multiple sclerosis, undergoing rehabilitation was conducted. All patients were assessed at the same time on both the FIM™ and the Barthel Index. The International Classification of Functioning, Disability and Health Linking Rules were used to establish conceptual coherency between the 2 scales, and the Rasch measurement model to establish an exchange of the total scores. Results: Using the FIM™ motor scale, items from both scales linked to the International Classification of Functioning, Disability and Health d4 Mobility or d5 Self-care chapters. Their co-calibration satisfied the assumptions of the Rasch model for each of 3 diagnostic groups. A ceiling effect was observed for the Barthel Index when contrasted against the FIM™ motor scale. Conclusion: Having a Rasch interval metric to transform scores between the FIM™ motor scale and Barthel Index is valuable for monitoring functioning, meta-analysis, quality audits and hospital benchmarking

Revisiting the disabilities of the arm, shoulder and hand (DASH) and QuickDASH in rheumatoid arthritis

Background Limitations in upper limb functioning are common in Musculoskeletal disorders and the Disabilities of the Arm, Shoulder and Hand scale (DASH) has gained widespread use in this context. However, various concerns have been raised about its construct validity and so this study seeks to examine this and other psychometric aspects of both the DASH and QuickDASH from a modern test theory perspective. Methods Participants in the study were eligible if they had a confirmed diagnosis of Rheumatoid Arthritis (RA). They were mailed a questionnaire booklet which included the DASH. Construct validity was examined by fit to the Rasch measurement model. The degree of precision of both the DASH and QuickDASH were considered through their Standard Error of Measurement (SEM). Results Three hundred and thirty-seven subjects with confirmed RA took part, with a mean age of 62.0 years (SD12.1); 73.6% (n = 252) were female. The median standardized score on the DASH was 33 (IQR 17.5–55.0). Significant misfit of the DASH and QuickDASH was observed but, after accommodating local dependency among items in a two-testlet solution, satisfactory fit was obtained, supporting the unidimensionality of the total sets and the sufficiency of the raw (ordinal or standardized) scores. Conclusion Having accommodated local response dependency in the DASH and QuickDASH item sets, their total scores are shown to be valid, given they satisfy the Rasch model assumptions. The Rasch transformation should be used whenever all items are used to calculate a change score, or to apply parametric statistics within an RA population. Significance and innovations Most previous modern psychometric analyses of both the DASH and QuickDASH have failed to fully address the effect of a breach of the local independence assumption upon construct validity. Accommodating this problem by creating ‘super items’ or testlets, removes this effect and shows that both versions of the scale are valid and unidimensional, as applied with a bi-factor equivalent solution to an RA population. The Standard Error of Measurement of a scale can be biased by failing to take into account the local dependency in the data which inflates reliability and thus making the SEM appear better (i.e. smaller) than the true value without bias. </ul

Towards the system-wide implementation of the International Classification of Functioning, Disability and Health in routine practice: Lessons from a pilot study in China

In 2011 the Chinese leadership in rehabilitation, in collaboration with the International Classification of Functioning, Disability and Health (ICF) Research Branch, embarked on an effort towards the system-wide implementation of the ICF in the healthcare system in China. We report here on the lessons learned from the pilot phase of testing the ICF Generic Set, a parsimonious set of 7 ICF categories, which have been shown to best describe functioning across the general population and people with various health conditions, for use in routine clinical practice in China. The paper discusses whether classification and measurement are compatible, what number of ICF categories should be included in data collection in routine practice, and the usefulness of a functioning profile and functioning score in clinical practice and health research planning. In addition, the paper reflects on the use of ICF qualifiers in a rating scale and the particularities of certain ICF categories contained in the ICF Generic Set when used as items in the context of Chinese rehabilitation and healthcare. Finally, the steps required to enhance the utility of system-wide implementation of the ICF in rehabilitation and healthcare services are set out.Chinese Mainland Affairs Offic

Toward standardized reporting for a cohort study on functioning: The Swiss Spinal Cord Injury Cohort Study

OBJECTIVE: Functioning is an important outcome to measure in cohort studies. Clear and operational outcomes are needed to judge the quality of a cohort study. This paper outlines guiding principles for reporting functioning in cohort studies and addresses some outstanding issues.DESIGN: Principles of how to standardize reporting of data from a cohort study on functioning, by deriving scores that are most useful for further statistical analysis and reporting, are outlined. The Swiss Spinal Cord Injury Cohort Study Community Survey serves as a case in point to provide a practical application of these principles.METHODS AND RESULTS: Development of reporting scores must be conceptually coherent and metrically sound. The International Classification of Functioning, Disability and Health (ICF) can serve as the frame of reference for this, with its categories serving as reference units for reporting. To derive a score for further statistical analysis and reporting, items measuring a single latent trait must be invariant across groups. The Rasch measurement model is well suited to test these assumptions.CONCLUSION: Our approach is a valuable guide for researchers and clinicians, as it fosters comparability of data, strengthens the comprehensiveness of scope, and provides invariant, interval-scaled data for further statistical analyses of functioning.<br/

Towards system-wide implementation of the International Classification of Functioning, Disability and Health (ICF) in routine practice: Developing simple, intuitive descriptions of ICF categories in the ICF Generic and Rehabilitation Set

Objective: A national, multi-phase, consensus process to develop simple, intuitive descriptions of International Classification of Functioning, Disability and Health (ICF) categories contained in the ICF Generic and Rehabilitation Sets, with the aim of enhancing the utility of the ICF in routine clinical practice, is presented in this study.Methods: A multi-stage, national, consensus process was conducted. The consensus process involved 3 expert groups and consisted of a preparatory phase, a consensus conference with consecutive working groups and 3 voting rounds (votes A, B and C), followed by an implementation phase. In the consensus conference, participants first voted on whether they agreed that an initially developed proposal for simple, intuitive descriptions of an ICF category was in fact simple and intuitive.Results: The consensus conference was held in August 2014 in mainland China. Twenty-one people with a background in physical medicine and rehabilitation participated in the consensus process. Four ICF categories achieved consensus in vote A, 16 in vote B, and 8 in vote C.Discussion: This process can be seen as part of a larger effort towards the system-wide implementation of the ICF in routine clinical and rehabilitation practice to allow for the regular and comprehensive evaluation of health outcomes most relevant for the monitoring of quality of care.Chinese Mainland Affairs Offic

Towards the system-wide implementation of the International Classification of Functioning, Disability, and Health in routine clinical practice: Empirical findings of a pilot study from Mainland China

Objective: The aims of this study were to evaluate the feasibility of using the International Classification of Functioning, Disability and Health (ICF) Generic Set in routine clinical practice, and of creating a functioning score based on it, and, subsequently, to examine its sensitivity to change.Methods: In this prospective cohort study, data from 761 adult inpatients from 21 Chinese hospitals were analysed. Each patient was assessed at admission and discharge. Feasibility was evaluated by analysing mean assessment time. The Rasch model was used to create a metric of functioning. Sensitivity to change was analysed with mixed-effects regression and by calculating standardized effect size based on Cohen's f2.Results: Mean duration of assessment was 5.3 min, with a significant decrease between admission and discharge. After removal of the item remunerative employment, the remaining ICF Generic Set categories fitted the Rasch model well. With a mean improvement in functioning of 12.1(95% confidence interval (95% CI):11.5-12.6), this metric proved sensitive to change, both in terms of statistical significance (p &lt; 0.001) and standardized effect size (Cohen's f2=2.35).Discussion: The ICF Generic Set is feasible for use in routine clinical practice and is promising to serve as the basis for the development of a functioning score that is sensitive to change.Chinese Mainland Affairs Offic

Super congruences and Euler numbers

Let $p>3$ be a prime. We prove that $$\sum_{k=0}^{p-1}\binom{2k}{k}/2^k=(-1)^{(p-1)/2}-p^2E_{p-3} (mod p^3),$$ $$\sum_{k=1}^{(p-1)/2}\binom{2k}{k}/k=(-1)^{(p+1)/2}8/3*pE_{p-3} (mod p^2),$$ $$\sum_{k=0}^{(p-1)/2}\binom{2k}{k}^2/16^k=(-1)^{(p-1)/2}+p^2E_{p-3} (mod p^3)$$, where E_0,E_1,E_2,... are Euler numbers. Our new approach is of combinatorial nature. We also formulate many conjectures concerning super congruences and relate most of them to Euler numbers or Bernoulli numbers. Motivated by our investigation of super congruences, we also raise a conjecture on 7 new series for $\pi^2$, $\pi^{-2}$ and the constant $K:=\sum_{k>0}(k/3)/k^2$ (with (-) the Jacobi symbol), two of which are $$\sum_{k=1}^\infty(10k-3)8^k/(k^3\binom{2k}{k}^2\binom{3k}{k})=\pi^2/2$$ and $$\sum_{k>0}(15k-4)(-27)^{k-1}/(k^3\binom{2k}{k}^2\binom{3k}k)=K.$