Gerold Stucki

ICF linking rules : an update based on lessons learned

OBJECTIVE Outcome research seeks to understand the end results of health services. Researchers use a wide variety of outcome measures including technical, clinical and patient-oriented measures. The International Classification of Functioning, Disability and Health (ICF) as a common reference framework for functioning may contribute to improved outcome research. The objective of this paper is to provide an updated version of the linking rules published in 2002 and illustrate how these rules are applied to link technical and clinical measures, health-status measures and interventions to the ICF. RESULTS Three specific linking rules have been established to link health-status measures to the ICF and one specific linking rule has been created to link technical and clinical measures and interventions. A total of 8 linking rules have been established for use with all different outcome measures and with interventions. CONCLUSION The newly updated linking rules will allow researchers systematically to link and compare meaningful concepts contained in them. This should prove extremely useful in selecting the most appropriate outcome measures among a number of candidate measures for the applied interventions. Further possible applications are the operationalization of concrete ICF categories using specific measures or the creation of ICF category-based item bankings.

Linking health-status measurements to the International Classification of Functioning, Disability and Health

With the approval of the International Classification of Functioning, Disability and Health by the World Health Assembly in May 2001, the concurrent use of both health-status measures and the International Classification of Functioning, Disability and Health is expected. It is therefore important to understand the relationship between these two concepts. The objective of this paper is to provide a systematic and standardized approach when linking health-status measures to the International Classification of Functioning, Disability and Health. The specific aims are to develop rules, to test their reliability and to illustrate these rules with examples. Ten linking rules and an example of their use are presented in this paper. The percentage agreement between two health professionals for 8 health-status instruments tested is also presented. A high level of agreement between the health professionals reflects that the linking rules established in this study allow the sound linking of items from health-status measures to the International Classification of Functioning, Disability and Health.

ASAS/EULAR recommendations for the management of ankylosing spondylitis

Objective: To develop evidence based recommendations for the management of ankylosing spondylitis (AS) as a combined effort of the ‘ASsessment in AS’ international working group and the European League Against Rheumatism. Methods: Each of the 22 participants was asked to contribute up to 15 propositions describing key clinical aspects of AS management. A Delphi process was used to select 10 final propositions. A systematic literature search was then performed to obtain scientific evidence for each proposition. Outcome data for efficacy, adverse effects, and cost effectiveness were abstracted. The effect size, relative risk, number needed to treat, and incremental cost effectiveness ratio were calculated. On the basis of the search results, 10 major recommendations for the management of AS were constructed. The strength of recommendation was assessed based on the strength of the literature evidence, risk-benefit trade-off, and clinical expertise. Results: The final recommendations considered the use of non-steroidal anti-inflammatory drugs (NSAIDs) (conventional NSAIDs, coxibs, and co-prescription of gastroprotective agents), disease modifying antirheumatic drugs, treatments with biological agents, simple analgesics, local and systemic steroids, non-pharmacological treatment (including education, exercise, and physiotherapy), and surgical interventions. Three general recommendations were also included. Research evidence (categories I–IV) supported 11 interventions in the treatment of AS. Strength of recommendation varied, depending on the category of evidence and expert opinion. Conclusion: Ten key recommendations for the treatment of AS were developed and assessed using a combination of research based evidence and expert consensus. Regular updating will be carried out to keep abreast of new developments in the management of AS.

Value and application of the ICF in rehabilitation medicine

Context: Rehabilitation medicine may be defined as the multi- and interdisciplinary management of a persons functioning and health. Rehabilitation medicine defines itself with respect to concepts of functioning, disability and health. Assessment and intervention management rely on these concepts. The current framework of disability--the WHO International Classification of Functioning, Disability and Health (ICF)--providing a coherent view of health from a biological, individual and social perspective. Issue: However, ICF success will depend on its compatibility with measures used in rehabilitation and on the improvement of its practicability. Thus, it is expected to see the development of the ICF based on versions of currently used instruments and on the development of ICF core sets. Conclusion: The new language ICF is an exciting landmark event for rehabilitation. It may lead to a stronger position of rehabilitation within the medical community, change multi-professional communication and improve communication between patients and rehabilitation professionals.

Smallest detectable and minimal clinically important differences of rehabilitation intervention with their implications for required sample sizes using WOMAC and SF-36 quality of life measurement instruments in patients with Osteoarthritis of the lower extremities

OBJECTIVE To discuss the concepts of the minimal clinically important difference (MCID) and the smallest detectable difference (SDD) and to examine their relation to required sample sizes for future studies using concrete data of the condition-specific Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the generic Medical Outcomes Study 36-Item Short Form (SF-36) in patients with osteoarthritis of the lower extremities undergoing a comprehensive inpatient rehabilitation intervention. METHODS SDD and MCID were determined in a prospective study of 122 patients before a comprehensive inpatient rehabilitation intervention and at the 3-month followup. MCID was assessed by the transition method. Required SDD and sample sizes were determined by applying normal approximation and taking into account the calculation of power. RESULTS In the WOMAC sections the SDD and MCID ranged from 0.51 to 1.33 points (scale 0 to 10), and in the SF-36 sections the SDD and MCID ranged from 2.0 to 7.8 points (scale 0 to 100). Both questionnaires showed 2 moderately responsive sections that led to required sample sizes of 40 to 325 per treatment arm for a clinical study with unpaired data or total for paired followup data. CONCLUSION In rehabilitation intervention, effects larger than 12% of baseline score (6% of maximal score) can be attained and detected as MCID by the transition method in both the WOMAC and the SF-36. Effects of this size lead to reasonable sample sizes for future studies lying below n = 300. The same holds true for moderately responsive questionnaire sections with effect sizes higher than 0.25. When designing studies, assumed effects below the MCID may be detectable but are clinically meaningless.

Development of ICF Core Sets for patients with chronic conditions

OBJECTIVE The objective of the ICF Core Sets project is the development of internationally agreed Brief ICF Core Sets and Comprehensive ICF Core Sets. METHODS The methods to develop both ICF Core Sets, the Comprehensive ICF Core Set and the Brief ICF Core Set, involved a formal decision-making and consensus process integrating evidence gathered from preliminary studies and expert opinion. RESULTS The results regarding the development of the ICF Core Sets for 12 health conditions (chronic widespread pain, low back pain, osteoarthritis, osteoporosis, rheumatoid arthritis, chronic ischemic heart disease, diabetes mellitus, obesity, obstructive pulmonary diseases, breast cancer, depression, and stroke) are presented in this supplement. CONCLUSION Both, the Brief ICF Core Sets and the Comprehensive ICF Core Sets are preliminary and need to be tested in the coming years based on a standardized protocol in close cooperation with the ICF research branch of the WHO FIC CC (DIMDI) in Munich and the CAS team at WHO. The final goals are valid and globally agreed tools to be used in clinical practice, research and health statistics.

Application of the International Classification of Functioning, Disability and Health (ICF) in clinical practice

(2002). Application of the International Classification of Functioning, Disability and Health (ICF) in clinical practice. Disability and Rehabilitation: Vol. 24, No. 5, pp. 281-282.

ICF Core Sets for stroke.

OBJECTIVE To report on the results of the consensus process integrating evidence from preliminary studies to develop the first version of the Comprehensive ICF Core Set and the Brief ICF Core Set for stroke. METHODS A formal decision-making and consensus process integrating evidence gathered from preliminary studies was followed. Preliminary studies included a Delphi exercise, a systematic review, and an empirical data collection. After training in the ICF and based on these preliminary studies relevant ICF categories were identified in a formal consensus process by international experts from different backgrounds. RESULTS The preliminary studies identified a set of 448 ICF categories at the second, third and fourth ICF levels with 193 categories on body functions, 26 on body structures, 165 on activities and participation, and 64 on environmental factors. Thirty-nine experts from 12 different countries attended the consensus conference on stroke. Altogether 130 second-level categories were included in the Comprehensive ICF Core Set with 41 categories from the component body functions, 5 from body structures, 51 from activities and participation, and 33 from environmental factors. The Brief ICF Core Set included a total of 18 second-level categories (6 on body functions, 2 on body structures, 7 on activities and participation, and 3 on environmental factors). CONCLUSION A formal consensus process integrating evidence and expert opinion based on the ICF framework and classification led to the definition of ICF Core Sets for stroke. Both the Comprehensive ICF Core Set and the Brief ICF Core Set were defined.

Relative responsiveness of condition-specific and generic health status measures in degenerative lumbar spinal stenosis.

The objective of this study was to compare the relative responsiveness of a condition-specific spinal stenosis measure and two generic health status measures for outcome assessment of surgery for degenerative lumbar spinal stenosis, and to examine whether responsiveness statistics and measures of the ability to distinguish clinically important improvement rank the instruments consistently. Physical function and symptom severity scales of the spinal stenosis measure were compared to the Sickness Impact Profile (SIP) and the Roland scale, which is derived from the SIP. Responsiveness was calculated with the standardized response mean, the effect size, and Guyatts responsiveness statistic. The discriminative ability of the instruments to distinguish patients who improved from those who did not was assessed using satisfaction with surgery as an external criterion. Minimal clinically relevant improvement was estimated using patient satisfaction as the external criterion. All responsiveness statistics revealed the same order of responsiveness; the physical function scale (SRM = 1.07) and symptom severity scales (SRM = 0.96) were more responsive than the Roland scale (SRM = 0.77) which was only slightly more responsive than the SIP (SRM = 0.69). Strikingly, the physical dimension of the SIP (SRM = 0.62) was even less responsive than the global SIP. The shape of and the area under the ROC curves showed that the physical function and symptom severity scales discriminate better between satisfied and unsatisfied patients than the Roland scale and SIP. The sensitivity to detect clinically important changes was somewhat lower at the ends of the scales, especially for the SIP and the Roland scale. Statistical approaches that assess the ability to distinguish clinically important changes and overall responsiveness statistics ranked the measures consistently. On the basis of these findings, we suggest that a condition-specific spinal stenosis measure is preferable as the primary end point in evaluative studies of degenerative lumbar spinal stenosis.

Measurement properties of a self-administered outcome measure in lumbar spinal stenosis.

Study Design The measurement properties and validity of a newly developed patient questionnaire for the assessment of patients with lumbar spinal stenosis was tested in an ongoing prospective multicenter observational study of patients undergoing decompressive surgery in three teaching hospitals. Objective The goal of the study was to develop a short, self‐administered questionnaire on symptom severity, physical functional status, and patient satisfaction. Summary of Background Data The measure is intended to complement existing generic measures of spinal‐related disability and health status. The questionnaire includes three scales with seven questions on symptom severity, five on physical function, and six on satisfaction. Methods The internal consistency of the scales was assessed with Cronbachs coefficient alpha on crosssectional data from 193 patients before surgery. The test‐retest reliability was assessed on data from a random sample of 23 patients using Spearmans rank correlation coefficient. The responsiveness was assessed on 130 patients with 6‐month follow‐up data using the standardized response mean. Results The test‐retest reliability of the scales ranged from 0.82 to 0.96, the internal consistency from 0.64 to 0.92, and the responsiveness from 0.96 to 1.07. The direction, statistical significance, and strength of hypothesized relationships with external criteria were as expected. Conclusions This short self‐administered spinal stenosis measure is reproducible, internally consistent, valid, and highly responsive. It can be used to complement generic instruments in outcome assessment of patients with lumbar spinal stenosis.