Abstracts

Introduction

Information on functioning and disability has become increasingly important to describe health and health-related states of people with any kind of health conditions. Functioning-related concepts, classifications and measurements play a central role in clinical practice, teaching and research ¹1. Stucki G, Cieza A. The International Classification of Functioning, Disability and Health (ICF) Core Sets for rheumatoid arthritis: a way to specify functioning. Ann Rheum Dis 2004; 63 Suppl 2:ii40-ii45.. In addition, functioning is considered a Clinical Outcome Assessment (COA), which means that it can be used as a clinical assessment to measure patient outcome in a clinical trial ²2. Walton MK, Powers JH, Hobart J, Patrick D, Marquis P, Vamvakas S, et al. Clinical outcome assessments: conceptual foundation-report of the ISPOR Clinical Outcomes Assessment-Emerging Good Practices for Outcomes Research Task Force. Value Health 2015; 18:741-52., as we can see in some papers already published ³3. Galvão DA, Spry N, Denham J, Taaffe DR, Cormie P, Joseph D, et al. A multicentre year-long randomised controlled trial of exercise training targeting physical functioning in men with prostate cancer previously treated with androgen suppression and radiation from TROG 03.04 RADAR. Eur Urol 2014; 65:856-64.^,44. Yavuzer G, Senel A, Atay MB, Stam HJ. "'Playstation eyetoy games'" improve upper extremity-related motor functioning in subacute stroke: a randomized controlled clinical trial. Eur J Phys Rehabil Med 2008; 44:237-44.^,55. Bahorik AL, Sterling SA, Campbell CI, Weisner C, Ramo D, Satre DD. Medical and non-medical marijuana use in depression: longitudinal associations with suicidal ideation, everyday functioning, and psychiatry service utilization. J Affect Disord 2018; 241:8-14.^,66. Monson CM, Shields N, Suvak MK, Lane JEM, Shnaider P, Landy MSH, et al. A randomized controlled effectiveness trial of training strategies in cognitive processing therapy for posttraumatic stress disorder: impact on patient outcomes. Behav Res Ther 2018; 110:31-40.^,77. Myrhaug HT, Odgaard-Jensen J, Østensjø S, Vøllestad NK, Jahnsen R. Effects of a conductive education course in young children with cerebral palsy: a randomized controlled trial. Dev Neurorehabil 2018; 21:481-9.. As a COA, functioning has been used in several health fields, e.g. in the health care of people with schizophrenia ⁸8. Rosa AR, Reinares M, Michalak EE, Bonnin CM, Sole B, Franco C, et al. Functional impairment and disability across mood states in bipolar disorder. Value Health 2010; 13:984-8.; migraine ⁹9. Pathak DS, Chisolm DJ, Weis KA. Functional Assessment in Migraine (FAIM) questionnaire: development of an instrument based upon the WHO's International Classification of Functioning, Disability, and Health. Value Health 2005; 8:591-600.; cancer ¹⁰10. Rowen D, Brazier J, Young T, Gaugris S, Craig BM, King MT, et al. Deriving a preference-based measure for cancer using the EORTC QLQ-C30. Value Health 2011; 14:721-31.; arthrogryposis ¹¹11. Steen U, Wekre LL, Vøllestad NK. Physical functioning and activities of daily living in adults with amyoplasia, the most common form of arthrogryposis. A cross-sectional study. Disabil Rehabil 2018; 40:2767-79.; dyspnea ¹²12. Larsen KSR, Petersen AK, Lisby M, Knudsen MV. Dyspnoea and self-management strategies in patients admitted to the emergency department: a study of patients' experiences. J Clin Nurs 2018; 27:4112-8.; stroke ¹³13. Magaard G, Wester P, Levi R, Lindvall P, Gustafsson E, Nazemroaya Sedeh A, et al. Identifying unmet rehabilitation needs in patients after stroke with a Graphic Rehab-CompassTM. J Stroke Cerebrovasc Dis 2018; 27:3224-35.; chronic musculoskeletal pain ¹⁴14. Tseli E, Stålnacke B-M, Boersma K, Enthoven P, Gerdle B, Äng BO, et al. Prognostic factors for physical functioning after multidisciplinary rehabilitation in patients with chronic musculoskeletal pain. Clin J Pain 2019; 35:148-73.; congenital heart disease ¹⁵15. Kovacs AH, Kaufman TM, Broberg CS. Cardiac rehabilitation for adults with congenital heart disease: physical and psychosocial considerations. Can J Cardiol 2018; 34(10 Suppl 2):S270-S7; and prior to hematopoietic stem cell transplantation ¹⁶16. van Haren IEPM, Staal JB, Potting CM, Atsma F, Hoogeboom TJ, Blijlevens NMA, et al. Physical exercise prior to hematopoietic stem cell transplantation: a feasibility study. Physiother Theory Pract 2018; 34:747-56..

In the public health field, the importance of functioning is growing gradually. There are discussions about its use as a third health indicator, in addition to mortality and morbidity. As a set, these 3 health indicators could offer more reliable information on the performance of health strategies in the health systems. Functioning could be used along with mortality and morbidity in prevention and promotion of health; as an indicator for rehabilitation; as an indicator for curative health services; and for palliative health care. In all the five fields cited, the morbidity and mortality without functioning fail to provide comprehensive information to the health management ¹⁷17. Stucki G, Bickenbach J. Functioning: the third health indicator in the health system and the key indicator for rehabilitation. Eur J Phys Rehabil Med 2017; 53:134-8.. In a country with an equitable health system, knowing the population functioning profile may be more important than knowing the occurrence of diseases and their deaths in this population. Only with the functioning information can we know their true health care needs ¹⁷17. Stucki G, Bickenbach J. Functioning: the third health indicator in the health system and the key indicator for rehabilitation. Eur J Phys Rehabil Med 2017; 53:134-8.. Strategies of functioning information collection in health surveys are also laid down in the literature ¹⁸18. Castro SS, Castaneda L, Araújo ES, Buchalla CM. Aferição de funcionalidade em inquéritos de saúde no Brasil: discussão sobre instrumentos baseados na Classificação Internacional de Funcionalidade, Incapacidade e Saúde (CIF). Rev Bras Epidemiol 2016; 19:679-87.. Some tools as the Model Disability Survey - MDS ¹⁹19. Cieza A, Sabariego C, Bickenbach J, Chatterji S. Rethinking Disability. BMC Med 2018; 16:10-4. and the World Health Organization Disability Assessment Schedule - WHODAS can be used ²⁰20. Antunes A, Frasquilho D, Azeredo-Lopes S, Neto D, Silva M, Cardoso G, et al. Disability and common mental disorders: results from the World Mental Health Survey Initiative Portugal. Eur Psychiatry 2018; 49:56-61.. Reinforcing the functioning role in the public health field, the 11 ^th International Classification of Disease - ICD-11 (https://icd.who.int/browse11/l-m/en) came up with a new section, “V Supplementary section for functioning assessment” in order to “…allow creating functioning profiles and overall functioning scores for the individuals, which are suitable to describe and quantify the level of functioning associated with health conditions. To guide functioning assessment, the section includes two International Classification of Functioning, Disability and Health (ICF)-ground instruments developed by World Health Organization (WHO): the WHO Disability Assessment Schedule (WHODAS 2.0 36-item version), and the Model Disability Survey (MDS). The section is complemented by a generic set of functioning categories with a high explanatory power derived from the ICF Annex 9”. The inclusion of functioning assessment in the ICD shows its weight in monitoring the burden of health events.

According to the WHO, functioning is defined as a “generic term which includes body functions and structures, activities and participation. It indicates the positive aspects of the interaction between the individual (with a health condition) and its contextual factors (personal and environmental factors)” (WHO. International Classification of Functioning, Disability and Health. v. 2. http://www.who.int/classifications/icf/en/), whilst disability is an umbrella term for impairments of the body functions, activity limitations or participation restrictions. These conceptualizations of functioning and disability are the fundamental basis of the (ICF), that conceives functioning as a multiple dimensional concept, accepting the biopsychosocial perspective as its framework ²¹21. Kostanjsek N. Use of The International Classification of Functioning, Disability and Health (ICF) as a conceptual framework and common language for disability statistics and health information systems. BMC Public Health 2011; 11 Suppl 4:S3..

In the past 15 years, the ICF has been assimilated and discussed by the user community in clinical or research settings and with its use some critiques have arisen. One of the ICF strengths, its comprehensiveness, is also a point of criticism ²²22. Ptyushkin P, Vidmar G, Burger H, Marincek C. Use of the International Classification of Functioning, Disability, and health in traumatic brain injury rehabilitation. Am J Phys Med Rehabil 2012; 91(13 Suppl 1):S48-54.. To facilitate the use of the ICF and shorten its time-consuming application WHO started to develop and establish strategies to support the use and application of the ICF in a convenient and less time-consuming way. In line with this, ICF Core Sets ²³23. Selb M, Escorpizo R, Kostanjsek N, Stucki G, Üstün B, Cieza A. A guide on how to develop an International Classification of Functioning, Disability and health core set. Eur J Phys Rehabil Med 2015; 51:105-17., short lists of the ICF categories tailored to the specific needs of people with specific health conditions and ICF-based assessment tools such as the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) ²⁴24. Üstün T, Kostanjsek N, Chatterji S, Rehm J. Measuring health and disability: manual for WHO Disability Assessment Schedule (WHODAS 2.0). Geneva: World Health Organization; 2010. have been developed.

In this paper, we will provide some explanatory remarks on the latter one, the WHODAS 2.0. WHODAS 2.0 is a generic tool designed to assess functioning according to the ICF framework by using the following six functioning domains in people aged 18 years and over: cognition, mobility, self-care, getting along, life activities and participation. It consists of 36 questions in its long version: Cognition (6 questions); Mobility (5 questions); Self-care (4 items); Getting along (5 items); Life activities (8 questions); and Participation (8 items). Besides this 36-item version WHO also provides versions containing 12 questions and a hybrid version (12+24), in which questions can vary from a minimal of 5 to a maximal of 36. The application mode ranges from an interview version or self-administered version to a proxy version. For each version of the instrument there is a standardized version according to the format of the respondent (interview, self-administered and proxy). In all versions, functioning is being assessed by a general score ranging from 0 (no disability) to 100 (full disability), with the 36 item-versions allowing also scores for domains ²⁵25. Castro SS, Leite CF. Translation and cross-cultural adaptation of the World Health Organization Disability Assessment Schedule - WHODAS 2.0. Fisioter Pesqui 2017; 24:385-91..

Since its publication in 2010, the WHODAS has been translated into several languages, always dependent on WHO’s approval. There are translations into more than 47 languages and dialects ²⁶26. Federici S, Bracalenti M, Meloni F, Luciano JV. World Health Organization disability assessment schedule 2.0: an international systematic review. Disabil Rehabil 2017; 39:2347-80. such as Hebrew ²⁷27. Marom BS, Carel RS, Sharabi M, Ratzon NZ. Cross-cultural adaptation of the World Health Organization Disability Assessment Schedule 2.0 (WHODAS 2.0) for Hebrew-speaking subjects with and without hand injury. Disabil Rehabil 2017; 39:1155-61.; Chinese ²⁸28. Cheung MKT, Hung ATF, Poon PKK, Fong DYT, Li LSW, Chow ESL, et al. Validation of the World Health Organization Assessment Schedule II Chinese Traditional Version (WHODAS II CT) in persons with disabilities and chronic illnesses for Chinese population. Disabil Rehabil 2015; 37:1902-7.; Polish ²⁹29. Cwirlej-Sozanska A, Wilmowska-Pietruszynska A, Sozanski B. Validation of the Polish version of the World Health Organization Disability Assessment Schedule (WHODAS 2.0) in an elderly population (60-70 years old). Int J Occup Saf Ergon 2018; 24:386-94.; Japanese ³⁰30. Tazaki M, Yamaguchi T, Yatsunami M, Nakane Y. Measuring functional health among the elderly: development of the Japanese version of the World Health Organization Disability Assessment Schedule II. Int J Rehabil Res 2014; 37:48-53.; Norwegian ³¹31. Moen VP, Drageset J, Eide GE, Klokkerud M, Gjesdal S. Validation of World Health Organization Assessment Schedule 2.0 in specialized somatic rehabilitation services in Norway. Qual Life Res 2017; 26:505-14.; and Portuguese ²⁵25. Castro SS, Leite CF. Translation and cross-cultural adaptation of the World Health Organization Disability Assessment Schedule - WHODAS 2.0. Fisioter Pesqui 2017; 24:385-91.; just to name a few. Translations and cross-cultural adaptations have been welcomed by WHO as the WHODAS is intended to be one of the favorite tools to measure health and disability across cultures in a standardized way ³²32. Üstün T, Kostanjsek N, Chatterji S, Rehm J. Measuring health and disability: manual for WHO disability assessment schedule. WHODAS 2.0. http://apps.who.int/iris/bitstream/10665/43974/1/9789241547598_eng.pdf (accessed on 27/Mar/2014).
http://apps.who.int/iris/bitstream/10665... . Besides that, a tool aiming to assess functioning in a standardized, less time-consuming and straightforward way could facilitate the assessment and more specifically the identification of needs in health care; matching treatments and interventions; measuring clinical and research outcomes and effectiveness; setting clinical priorities; and allocating resources ³²32. Üstün T, Kostanjsek N, Chatterji S, Rehm J. Measuring health and disability: manual for WHO disability assessment schedule. WHODAS 2.0. http://apps.who.int/iris/bitstream/10665/43974/1/9789241547598_eng.pdf (accessed on 27/Mar/2014).
http://apps.who.int/iris/bitstream/10665... .

With WHO’s endorsement, WHODAS 2.0 has had its use spread gradually and quickly throughout the world in clinical and research settings ²⁶26. Federici S, Bracalenti M, Meloni F, Luciano JV. World Health Organization disability assessment schedule 2.0: an international systematic review. Disabil Rehabil 2017; 39:2347-80.. As a result of this, the literature has shown some examples of its use as in the assessment of functioning in aged population in Poland ³³33. Cwirlej-Sozanska A, Wilmowska-Pietruszynska A. Assessment of health, functioning and disability of a population aged 60-70 in south-eastern Poland using the WHO Disability Assessment Schedule (WHODAS 2.0). Ann Agric Environ Med 2018; 25:124-30.; in the check for the association between disability and common mental disorders ²⁰20. Antunes A, Frasquilho D, Azeredo-Lopes S, Neto D, Silva M, Cardoso G, et al. Disability and common mental disorders: results from the World Mental Health Survey Initiative Portugal. Eur Psychiatry 2018; 49:56-61.; in the research of the symptoms of depression and anxiety ³⁴34. Adewuya AO, Atilola O, Ola BA, Coker OA, Zachariah MP, Olugbile O, et al. Current prevalence, comorbidity and associated factors for symptoms of depression and generalised anxiety in the Lagos State Mental Health Survey (LSMHS), Nigeria. Compr Psychiatry 2018; 81:60-5.; in the description of the gap in activities and participation between people with and without disabilities ³⁵35. Chiu T-Y, Yen C-F, Escorpizo R, Chi W-C, Liou T-H, Liao H-F, et al. What is the gap in activity and participation between people with disability and the general population in Taiwan? Int J Equity Health 2017; 16:136.; in the analysis of the participation of colorectal cancer survivors ³⁶36. Lee HH, Shin E-K, Shin H-I, Yang EJ. Is WHODAS 2.0 Useful for Colorectal Cancer Survivors? Ann Rehabil Med 2017; 41:667-6.; relating educational level and disability in people with dementia ³⁷37. Huang S-W, Chi W-C, Yen C-F, Chang K-H, Liao H-F, Escorpizo R, et al. Does more education mean less disability in people with dementia? A large cross-sectional study in Taiwan. BMJ Open 2017; 7:e013841.; in the investigation of disability in people with HIV ³⁸38. Hanass-Hancock J, Myezwa H, Carpenter B. Disability and Living with HIV: Baseline from a Cohort of People on Long Term ART in South Africa. PLoS One 2015; 10:e0143936.; among others. Several papers with clinical approach can also be found. Reports of researches on evaluating mental functions in individuals with Huntington disease ³⁹39. Lai J-S, Goodnight S, Downing NR, Ready RE, Paulsen JS, Kratz AL, et al. Evaluating cognition in individuals with Huntington disease: Neuro-QoL cognitive functioning measures. Qual Life Res 2018; 27:811-22.; on assessing disability in men referred for treatment with work-related primary mental health care problems ⁴⁰40. Bailey S, Mushquash C, Haggarty J. Disability and psychiatric symptoms in men referred for treatment with work-related problems to primary mental health care. Healthcare 2017; 5:18.; on researching the effect of a community-based rehabilitation intervention for people with schizophrenia ⁴¹41. Asher L, De Silva M, Hanlon C, Weiss HA, Birhane R, Ejigu DA, et al. Community-based Rehabilitation Intervention for people with Schizophrenia in Ethiopia (RISE): study protocol for a cluster randomised controlled trial. Trials 2016; 17:299.; on investigating disability in patients undergoing neurosurgical procedures ⁴²42. Schiavolin S, Quintas R, Pagani M, Brock S, Acerbi F, Visintini S, et al. Quality of life, disability, well-being, and coping strategies in patients undergoing neurosurgical procedures: preoperative results in an Italian sample. ScientificWorldJournal 2014; 2014:790387.; on the knee posture during gait and global functioning post-stroke ⁴³43. Rosa MCN, Marques A, Demain S, Metcalf CD. Knee posture during gait and global functioning post-stroke: a theoretical ICF framework using current measures in stroke rehabilitation. Disabil Rehabil 2015; 37:904-13.; could be examples.

WHO mentions the following advantages for the use of WHODAS:

It has also been said that WHODAS can be considered a patient-reported outcome measure (PROM) with direct application in multidisciplinary services like community rehabilitation services ⁴⁴44. Kulnik ST, Nikoletou D. WHODAS 2.0 in community rehabilitation: A qualitative investigation into the validity of a generic patient-reported measure of disability. Disabil Rehabil 2014; 36:146-54.. Doubtless, the features presented above are strengths that would already favor the tool but WHODAS has yet another even more interesting feature. By using its domains and total scores it is possible to consider functioning as a quantifiable concept, ranging from 0 (no disability) to 100 (full disability), both for domain scores and for total score. The WHODAS scores will also provide the opportunity to compare and analyze functioning and disability in (clinical) population and subpopulations.

However, there are possible weaknesses or even inconsistencies that can only be seen in the practical application of the WHODAS. In Brazil, we have been working with WHODAS since 2015 and our experience is threefold: firstly, by becoming familiar with WHODAS conceptualization and content from reading the relevant literature; secondly, by translating the user’s manual to Portuguese and by adapting it for the Brazilian specific needs; and thirdly, by applying the WHODAS in a broad range for clinical and research settings in Brazil. In doing so, some inconsistencies have become evident in the process of translating, adapting and applying WHODAS to our research and clinical practice.

This paper aims to highlight these inconsistencies and to point out a set of proposals to cope with them from the Brazilian perspective. By presenting weaknesses of WHODAS and discussing how to cope with them, this paper (1) will contribute to its appropriate use in the health care process, benefiting professionals and researchers in the field of health and rehabilitation in Brazil and other countries in which WHODAS has been used, and (2) will provide a set of information to be considered in the case of preparing a revised version of the WHODAS and its manual.

Remarks on inconsistencies and weaknesses of the WHODAS along with proposals to cope with them

Reflections on the WHODAS layout

It is known that the layout of a questionnaire can impact the way how it is “understood” and filled in as well as the quality of data and time of application ⁴⁵45. Tourangeau R. Spacing, Position, and Order: Interpretive Heuristics for Visual Features of Survey Questions. Public Opin Q 2004; 68:368-93. and as a consequence the results retrieved from the analysis of the questionnaire such as prevalence and risk estimations ⁴⁶46. Ekerljung L, Rönmark E, Lötvall J, Wennergren G, Torén K, Lundbäck B. Questionnaire layout and wording influence prevalence and risk estimates of respiratory symptoms in a population cohort. Clin Respir J 2013; 7:53-63.. Therefore, it is essential to provide a questionnaire that is easy to apply and use in different populations.

The WHODAS manual states very clear recommendations for its application and scoring. Some instructions describe the application process and there are - for the interview version of the WHODAS - specific information about how to read the questions for the interviewee. An instruction is provided that the text in standard blue colored print should be read to the interviewee. It is well known that in many countries research funding issues are central and the budget is often limited. Printing colored texts implies higher costs for both, in research projects and in clinical use. To cope with this, we suggest the use of the standard print in bold; italic; capslock; or in grey color. So, the text would remain highlighted for the interviewers.

Furthermore, WHODAS uses two flashcards aiming “to provide a visual cue or reminder for the respondent about important pieces of information to remember while answering questions” ³²32. Üstün T, Kostanjsek N, Chatterji S, Rehm J. Measuring health and disability: manual for WHO disability assessment schedule. WHODAS 2.0. http://apps.who.int/iris/bitstream/10665/43974/1/9789241547598_eng.pdf (accessed on 27/Mar/2014).
http://apps.who.int/iris/bitstream/10665... . However, the flashcards cannot be used when applying the WHODAS in blind or illiterate people. Therefore, we suggest the use of cards printed in Braille. So, they can be read by blind people if needed. For illiterate and blind people who do not read Braille, we propose that the interviewer read the flashcards whenever the interviewee asks for them. With these suggestions, we assure the participation of the groups of people who are blind and the illiterate. It should be said that the prevalence of people with blindness can reach 8% in the Sub-Saharan Africa; in Brazil this prevalence was 3.6% in 2013 ⁴⁷47. Coordenação de Trabalho e Rendimento, Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional de Saúde, 2013: ciclos de vida. Brasil e grandes regiões. Rio de Janeiro: Instituto Brasileiro de Geografia e Estatística; 2015.; and in 2010 the amount of people with blindness around the world could come to 32.4 million ⁴⁸48. Stevens GA, White RA, Flaxman SR, Price H, Jonas JB, Keeffe J, et al. Global Prevalence of Vision Impairment and Blindness. Ophthalmology 2013; 120:2377-84.. The illiterate population can also be significant in some countries, as well. Some African nations, for example, can have more than 50% of its population illiterate ⁴⁹49. Institute for Statistics, United Nations Educational, Scientific and Cultural Organization. Literacy rates continue to rise from one generation to the next. Paris: United Nations Educational, Scientific and Cultural Organization. 2017, (Fact Sheet, 45).. Considering these indicators, it can be seen that failing to adapt WHODAS for its use in these groups may represent the exclusion of large population groups from the WHODAS application process, compromising the quality and representativeness of the research and finally the health care.

Comments on the WHODAS wording

The wording of a tool has a central role since it will deliver the message which will impact the information collection. Therefore, efforts must be made to ensure a wording that is as clear as possible.

The questions D6.4; D6.5 and D6.6 have in their beginning a wording which implies incoherence with the pattern of WHODAS responses (none; mild; moderate; severe; extreme or cannot do) (Box 1). Thus, the question D6.4 begins with “How much time did you spend on…”. Starting from this question, an answer related to time as “1 hour”; “12 hours”; “a day”; “a week”; or “a year” is expected. These alternatives are clearly different from those in WHODAS. Assuming the suggestions above were adopted, the heading of this question could be improved to “Manage the time you spent on your health condition or its consequences?”.

Questions D6.5 and D6.6 start both with “How much have…” (Box 2). This kind of question requires answers like “not at all”, “much”; “little”, among others.

The scientific literature on the validation of WHODAS shows worst confirmatory factor analysis (CFA) ⁵⁰50. Chiu T-Y, Yen C-F, Chou C-H, Lin J-D, Hwang A-W, Liao H-F, et al. Development of traditional Chinese version of World Health Organization Disability Assessment Schedule 2.0 36 - item (WHODAS 2.0) in Taiwan: validity and reliability analyses. Res Dev Disabil 2014; 35:2812-20. and exploratory factor analysis (EFA) ⁵¹51. Zhao HP, Liu Y, Li HL, Ma L, Zhang YJ, Wang J. Activity limitation and participation restrictions of breast cancer patients receiving chemotherapy: psychometric properties and validation of the Chinese version of the WHODAS 2.0. Qual Life Res 2013; 22:897-906. results for the questions D6.4 to D6.6.

The remarks on the wording of the WHODAS are essential as the wording of a questionnaire tremendously impacts the results ⁵²52. Babel P. The effect of question wording in Questionnaire surveys on placebo use in clinical practice. Eval Health Prof 2012; 35:447-61., consequences for the use of health services ⁵³53. Siegel PZ, Qualters JR, Mowery PD, Campostrini S, Leutzinger C, McQueen D V. Subgroup-specific effects of questionnaire wording on population-based estimates of mammography prevalence. Am J Public Health 2001; 91:817-20. and the prevalence of a health condition ⁵⁴54. Pescatore AM, Spycher BD, Beardsmore CS, Kuehni CE. "Attacks" or "whistling": impact of Questionnaire Wording on Wheeze Prevalence Estimates. PLoS One 2015; 10:e0131618..

Remarks about WHODAS scoring process

The sum score of a questionnaire should be carefully executed according to the recommendations of the instrument developers. In the case of WHODAS, two different scores can be computed, a simple and a complex one. We would like to dwell on the latter, the complex one. The WHODAS manual explains that the complex score is based on the “Item-Response-Theory - IRT” and considering the SPSS syntax presented, it is noticed that some variables have different weights. It remains unclear why only some variables were weighted and others were not. An explanation about the analysis would be very welcome for a better understanding of the weighting process.

The steps to compute the complex score were summed up in the manual with the following wording: “Step 1 - summing of recoded item scores within each domain. Step 2 - summing of all six domain scores. Step 3 - converting the summary score into a metric ranging from 0 to 100 (where 0 = no disability; 100 = full disability)”. The domain scores are not clearly marked up by a heading. It could make the syntax more comprehensible and easily applicable.

There is a SPSS syntax available at page 59 of the manual, and we understand that some improvements can be made to this material. The questions D5.6; D5.7 and D5.8 cannot be found at the “Recode of polytomous items” section and there are at the end of this section the questions D5.8; D5.9; D5.10 and D5.11. The last four questions cited here are also in another syntax section. The issue lies on the fact that the questions D5.9 to D5.11 do not have the WHODAS pattern of answers. So, it seems that they should not be present in its syntax.

Another relevant point is the analysis of the variables classified as “not applicable” - N/A. Some variables can be considered N/A if the respondent considers that the question does not apply to his/her situation, or that was not experienced by the respondent in the last 30 days. The main question is that the N/A variables are not “missing data”, so, they should not be treated like this. It seems that the command “compute” (used in the syntax) will result in a blank score if at least one of the component variables of the operation is missing (IBM SPSS Statistics 20 Core System User’s Guide IBM SPSS Statistics Options, 2011. https://www.csun.edu/sites/default/files/statistics20-core-system-guide-64bit.pdf). So, if one or more variables are blank, the scores may not be calculated, losing the answered questions. The total score could not be calculated as well. A suggested excel file is offered online to compute the scores (https://drive.google.com/open?id=1CB47ZIriCErjakSzqul0AgSyBX3f9Qmj).

It should be stressed out that tool revisions have already been documented by the scientific literature aiming to make the tool more comprehensible ⁵⁵55. Vrieze T, Vos L, Gebruers N, Groef A, Dams L, Gucht EV, et al. Revision of the Lymphedema Functioning, Disability and Health Questionnaire for Upper Limb Lymphedema (Lymph-ICF-UL): reliability and validity. Lymphatic Research and Biology 2019; 17:347-55.; socially adequate ⁵⁶56. Chen CH. Revision and validation of a scale to assess pregnancy stress. J Nurs Res 2015; 23:25-32.; or in order to fit with modern diagnosis approaches ⁵⁷57. Berthold SM, Mollica RF, Silove D, Tay AK, Lavelle J, Lindert J. The HTQ-5: revision of the Harvard Trauma Questionnaire for measuring torture, trauma and DSM-5 PTSD symptoms in refugee populations. Eur J Public Health 2019; 29:468-74. So, the presented proposal is not uncommon in the scientific setting.

Conclusions

This paper provides remarks on weaknesses or inconsistencies of the WHODAS 2.0 that became evident in the translation, cross-cultural adaptation and in the daily use of the tool in the research and clinical settings in Brazil. The remarks are related to the WHODAS layout, wording and scoring process. Strategies such as layout updating, sentence reformulation, and scoring process suitability can work around these problems.

Although the remarks do not question the overall advantages in the usage of WHODAS, they should be taken into account when revising the WHODAS and its Manual as well as its syntax.

References

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