The linking of amyotrophic lateral sclerosis disease-specific quality of life instruments to ICF with refined rules

Authors

Abstract

AimQuality of life (QoL) has emerged as a significant concept in the domains of healthcare and medicine. Amyotrophic Lateral Sclerosis (ALS) reduces the QoL of individuals by affecting various systems. The aim of this study is to link ALS-specific QoL assessments to ICF components.
MethodsThe ALS assessment questionnaire (ALSAQ-40) and short form (ALSAQ-5), and the ALS-specific quality of life revised (ALSQoL-R) and short form (ALSQoL-SF) were linked to ICF using refined rules by two independent researchers.
ResultsStatistical analysis results showed that the kappa value of 81.3% demonstrated almost perfect agreement between the researchers. A total of 115 concepts were defined in the study. Of the linked concepts, 54 were body functions, 54 were activity and participation, and 4 were environmental factors. All the instruments had items linked with items b152 “Emotional functions” and d330 “speaking” components.
ConclusionThe majority of the items of the ALSAQ-5, ALSAQ-40, ALSSQoL-SF, and ALSSQoL-R were linked to the activity and participation categories of ICF. The ALSQoL-R, ALSQoL-SF, and ALSAQ-40 were linked mostly to body functions. It was seen that ALSQoL-R had the most unique linked concepts in body functions, and ALSAQ-40 had the most comprehensive linked concepts in the context of activity and participation. It can be recommended that ALS-specific QoL instruments to be developed in the future include domains of ICF, products and technology, natural environment and human-made changes to the environment, services, systems and policies, recreation, and leisure.

Keywords

Introduction

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease of the central nervous system that results in the loss of upper and lower motor neurons in the cortex, brain stem and spinal cord.^1,2 According to recent studies, the incidence of ALS is between 0.6 and 3.8 per 100000 people, and prevalence is between 4.1 and 8.4 per 100.000 people. ALS is known to be 1-2-fold more common in males than females, and the age of disease onset has been reported to be 51-66 years.¹ ALS is categorized as sporadic or familial. The sporadic type accounts for approximately 90-95% of all cases, and the familial type for 5-10% of all cases due to their associated genetic inheritance factors.^3,4 Muscle weakness, twitches, and cramps are the most common symptoms in both types of ALS.^5,6 ALS reduces the QoL of individuals by affecting various systems.⁷
Quality of life (QoL) has emerged as a significant concept in the domains of healthcare and medicine, and is now emphasised in both study and practice. The World Health Organization (WHO), the current definition of QoL is “An individual’s perception of their position in life in the context of the culture in which they live and in relation to their goals, expectations, standards and concerns”.⁸ Understanding QoL is vital to be able to improve the symptom treatment, care, and rehabilitation of patients with ALS. QoL constructed within the strict boundaries of dependency has become even more crucial because of the progressive nature of ALS with a decline in life expectancy. Therefore, precise and disease-specific evaluation of QoL in patients with ALS is essential.
The International Classification of Functionality, Disability, and Health (ICF) is a comprehensive system designed to create a common language across different disciplines and fields to be able to improve the quality of service. The main categories of the ICF framework are functioning, disability, and contextual factors. Functioning and disability consist of body structures (s), body functions (b), and activity and participation (d). Contextual factors include environmental (e) and individual (pf) factors. The ICF presents a hierarchical taxonomy containing more than 1400 categories.⁹
Earlier studies have linked the ICF to a diverse range of diseases.^10,11,12,13 The linking of disease-specific instruments to the ICF is thought to guide the appropriate selection of scales to assess the areas in which patients experience functional loss. To the best of our knowledge, there is no research linking ALS-specific QoL assessments with the ICF. Therefore, the aim of this study was to link QoL assessments specific to ALS with ICF components. In line with this, the research question of our study is as follows:
• To what extent are ALS-specific quality of life scales linked to the ICF?
• Which subcategories of the ICF can ALS-specific quality of life scales be linked with?

Materials and Methods

The scales developed specifically for ALS and for evaluating QoL were determined with reference to the literature, and the scales used in this study were as follows:
The Amyotrophic Lateral Sclerosis Assessment Questionnaire (ALSAQ-40) was developed by Jenkinson et al. as a self-reported outcome measure to evaluate QoL specific to patients with ALS and motor neuron disease. The ALSAQ-40 includes 40 items in the five sub-parameters of physical mobility, activities of daily living/independence, eating and drinking, communication and emotional functioning.¹⁴ The patient responses refer to the last two weeks. Each item is scored between 0 and 4 points with the total score obtained by dividing by the maximum score that can be obtained from the scale. The final ALSAQ-40 score ranges from 0 to 100, with lower scores indicating better QoL, and higher scores indicating lower functional levels.¹⁴
The Amyotrophic Lateral Sclerosis Assessment Questionnaire Short Version (ALSAQ-5) is a revised version of the ALSAQ-40. The ALSAQ-5 consists of 5 items, each scored between 0 and 4 points by the patients, to give a total score then divided by the maximum score. The final score of the ALSAQ-5 varies between 0 and 100, with lower scores indicating better health, and higher scores indicating lower functional levels. In a previous study, the ALSAQ-5 showed a strong correlation with the ALSAQ-40.¹⁵
The Amyotrophic Lateral Sclerosis Specific Quality of Life-Revised (ALSSQOL-R) is a self-report outcome measure that evaluates QoL in patients with ALS. The ALSSQOL-R consists of 50 items in six sub-domains of negative emotion, interaction with people and the environment, intimacy, religiosity, physical symptoms, and bulbar function. Scoring is applied to 46 items, each scored between 0 and 10 points. The total score of the ALSSQOL-R ranges from 0 to 460, and the average score is calculated as the total of all the items divided by 46. A higher average score indicates better functional levels for QoL.¹⁶
The Amyotrophic Lateral Sclerosis Specific Quality of Life- Short Form (ALSSQOL-SF) is a revised version of the ALSSQOL-R. The 50-item scale was revised to the short form of 20 items in 2018.¹⁷ Each of the 20 items is scored between 0 and 10 points, to give a total score range of 0 to 200. The average score is calculated as the total of all the items divided by 20. A higher average score indicates better functionality for QoL.¹⁷
The ICF Linking ProcessThe ICF linking was made within the framework of the refined association rules set by Cieza et al. in 2016.¹⁸ The linking process was performed in three stages. In the first stage, the researchers investigated each item of all scales in order to identify main and secondary concepts. In the second stage, two researchers (MD, EAR) examined the perspectives and responses of each item. The perspectives were categorized as “Appraisal, Need or Dependency, Descriptive; Capacity and Descriptive; Performance”, and responses were categorised as “Intensity, Frequency, Agreement, Confirmation and Qualitative Attributes”. In the second stage, the main and secondary concepts of the relevant items were independently linked using an online website (https://apps.who.int/classifications/icfbrowser/). Concepts that could not be linked were classified as not definable; general health (ND-GH), not definable; physical health (ND-PH), not definable; mental health (ND-MH), not covered by the ICF (NC). In the third stage, three researchers (MD, EAR, and EA) came together and reviewed all the independently conducted stages. Disagreements were discussed. In cases of disagreement, we utilized a majority rule approach and a consensus was reached on linking. Additionally, if consensus was not reached, we consulted an external expert (EA) in ICF coding to provide an objective perspective and final decision on the appropriate codes. The language of all the materials used in the research was English.
Ethical ApprovalEthical and scientific rules were followed in all stages of the study; no changes were made to the data included in the study. Datas open to access on the internet were used in the study. Therefore, ethics committee approval is not required. All procedures performed within the scope of the research are in compliance with the “Declaration of Helsinki”.
Statistical AnalysisThe study was conducted between December 2022 and February 2023. Using SPSS vn. 26.0 software (IBM Corp., Armonk, NY, USA), the Kappa score was calculated to determine agreement between the evaluators. A Kappa score in the range of 0-1 and above 0.61 indicates good agreement.¹⁹ Frequency analysis was used to examine the distribution of scales for the ICF parameters.

Results

The results of the statistical analysis showed a kappa score of 81.3%, demonstrating almost perfect agreement between the researchers (p<0.001). Within the scope of this study, 116 items of four scales were examined, and 115 concepts were defined. Of the 115 concepts, 4 could not be linked to any ICF codes. These were defined as NC (2), ND-GH.¹ and ND-MH.¹ respectively. Of the linked concepts, 54 were body functions, 54 were activity and participation, and 4 were environmental factors. According to the perspective classification, 101 of the 116 items were determined as “appraisal” and 15 as “descriptive; capacity”. According to the response classification, 38 of the 116 items were determined as “intensity,” 57 as “frequency,” and 21 as “agreement.”
All concepts for the ALSAQ-5 were linked with ICF codes in Table 1. In the ALSAQ-40, 39 of the 40 concepts were linked with ICF in Table 1. In the ALSSQoL-R, 49 of the 50 concepts and all concepts for ALSSQoL-SF were linked with ICF codes in Table 2 and Table 3.

Discussion

Due to the progressive nature of ALS, both life expectancy and QoL of patients are adversely affected by the severity of the disease. The ICF allows many chronic and progressive diseases, such as ALS, to be examined in perspectives of a biopsychosocial model in accordance with patient expectations. Moreover, the linking of current instruments with ICF helps in the selection of appropriate assessments and treatments, thereby improving the quality of clinical decision-making processes and healthcare services. From this perspective, the results of this study can be considered to contribute to the success of treatment and rehabilitation of patients with ALS and to the promotion of disease-specific core set development processes. The most important results of this study were that all but one item for the 4 concepts were linked with the ICF, and all the items of the ALSAQ-5 and ALSSQoL-SF, which are among the QoL outcomes developed and used specifically for individuals with ALS, were linked with ICF.
Previous studies have stated that ALSSQoL-R, ALSSQoL-SF, ALSAQ-40, and ALSAQ-5 have been used to evaluate the disease-specific QoL in individuals with ALS.²⁰ In addition to these instruments, the Sickness Impact Profile (SIP), and Short Form-36 (SF-36) have been used to assess health-related generic QoL, and the WHOQOL-Bref, McGill QoL Questionnaire (MQoLQ), Schedule for the Evaluation of Individual QoL (SEIQoL) has been used to assess global QoL of ALS patients.⁷ Bernardelli et al. conducted a study based on refined rules of ICF linking for the SF-36 in 2021. A total of 67 concepts were identified, 49 of which could be linked to ICF. Approximately 22.4% of the concepts were linked to body functions, and 77.6% were linked to activity and participation components.²¹ Prodinger et al., Geyh et al. and Cieza et al. similarly stated that SF-36 is mostly linked with the activity and participation component of the ICF.^22,23,24 In a systematic review conducted by Ballert et al., participation assessment tools were examined in terms of ICF linking. According to the results of the study, 63 concepts were determined to link SF-36 with ICF, and 22.2% of these concepts were linked to body functions, 52.4% to activity and participation, and 4.8% to environmental factors. In addition, 59.4% of the concepts for the SIP scale and 22.7% of the defined concepts for the WHOQoL-BREF scale were linked to activity and participation.²⁵ The results of the current study showed that the majority of the items of the ALSAQ-5, ALSAQ-40, ALSSQoL-SF, and ALSSQoL-R were linked with activity and participation parameters of ICF, which was consistent with the literature. To the best of our knowledge, there are no other studies in the literature that have examined the linking of disease-specific QoL instruments with ICF. From the findings of this study, it was concluded that the ALSAQ-5 assessed activity and participation parameters the most. However, the ALSAQ-40 had the most distinct association relative to the number of questions when considering the depth of coverage for the linked concepts. When diversity in perspective classification is required, ALSQoL-R has the most unique linking of any disease-specific QoL instrument for ALS. It was also observed that the items for the ALSQoL-SF were linked with activity and participation parameters at similar rates to those previously reported in the literature, and all of the concepts could be linked within the scope of ICF. The findings of the current study demonstrate that generic and global QoL instruments and ALS-specific QoL instruments are similar in the context of rates for activity and participation.
Bernardelli et al. showed that the linked concepts for SF-36 were distributed under the umbrella of general tasks and demands (d2), mobility (d4), self-care (d5), domestic life (d6), major life areas (d8), community, social and civic life (d9) and mental functions (b1) categories of ICF.²¹ Similarly, according to Ballert et al., linked concepts for the SF-36 were distributed under the d4, d5, d8, and d9 categories. It has also been shown that concepts for SIP were linked with all d categories, and the linked concepts of WHOQoL-BREF were linked with d4, d7, d8, and d9.²⁵ According to the results of the current study, the categories b1, and communication (d3), d4, d5 were linked with the short version of ALSAQ-40 (ALSAQ-5), and in addition to these categories, sensory functions and pain (b2), voice and speech functions (b3), functions of the cardiovascular, haematological, immunological and respiratory systems (b4), functions of the digestive, metabolic and endocrine systems (b5), neuromusculoskeletal and movement-related functions (b7), d1 and d6 categories were linked with ALSAQ-40. In addition, categories b1, b2, b4, b7, d3, d7, d9, and supports and relationships (e3) were linked with ALSSQoL-SF; categories b5, genitourinary and reproductive functions (b6), and d5 were linked to ALSSQoL-R. These differences from the literature can be attributed to the fact that the instruments examined in this study covered the specific symptoms of ALS. This emphasizes the importance of using disease-specific QoL scales. Another important piece of evidence from the current study is that all the instruments had items linked with items b152 “Emotional functions” and d330 “speaking” components. Therefore, clinicians and researchers who aim to evaluate these concepts in ALS patients should use all scales related to the study. In addition, fatigue, which is an important factor affecting disease progression, seems to be associated with all scales except the ALSAQ-5.
When the differences between the instruments were examined, the ALSAQ-40 was found to be more inclusive in activities related to speech, voice, and mental functions; self-care; domestic life; and learning and applying knowledge. The ALSSQoL-R was found to be more inclusive in relation to ICF parameters in terms of mental, genitourinary, and reproductive functions, interpersonal communication, and social life. The ALSSQoL-R and ALSSQoL-SF can be considered to be useful tools for determining the functional capacity of patients since they contain a descriptive perspective. However, domains such as “products and technology, natural environment and human-made changes to environment, services, systems and policies, recreation, and leisure” that positively affect the QoL of patients with ALS and contribute to functionality and life span could not be associated with any of the instruments examined within the scope of this research. Therefore, it can be suggested that prioritizing these areas in the instruments to be developed in the future will contribute to the definition of QoL and inclusiveness of ICF. The results obtained from this study can be considered to contribute to target-oriented intervention approaches by providing guidance for the selection of an appropriate evaluation module.

Limitations

The most important limitation of this study was the small number of instruments examined. There is a need for further research of instrument linking, specific to the symptoms of the disease (severity, cognitive and behavioral status, etc.), so that ALS can be more extensively studied from the perspective of ICF. It would also be of benefit to correlate linking studies conducted on different nationalities and cultures to be able to generalize the obtained data to all populations. Another significant limitation of our research is that the ICF does not differentiate between the domains of activity and participation. We believe that this presents a challenge in interpreting the effects of ALS on patient activities and their participation in various life areas. Further, we suggest the need for a more refined classification system within the ICF or supplementary methods that can help delineate these two important components more clearly in future research.

Conclusion

For the first time in the literature, ALS-specific QoL instruments have been found to be mostly linked to ICF. The data obtained could contribute to the creation of a core set for ALS in the future and to the process of conducting clinical decision-making processes. The results of this research will also pave the way for the inclusion of the ICF perspective in the development of ALS-specific QoL instruments in the future.
Clinical Implications• The ALSAQ-40 is identified as offering the most comprehensive coverage in terms of depth for linked concepts, making it a valuable tool for a broad assessment of ALS patients’ needs.
• The ALSQoL-R is noted for its unique linking among disease-specific QoL instruments for ALS, providing a diverse perspective classification, essential for holistic patient assessment.
• Emotional functions and speaking components (b152 and d330 of ICF) are linked with all instruments, suggesting their essential role in evaluating ALS patients.
• The results provide crucial guidance for selecting appropriate evaluation modules, contributing to targeted intervention approaches in ALS patient care.

Declarations

References

1. Aktekin MR, Uysal H. Amyotrofik lateral skleroz epidemiyolojisi. Turk J Neurol. 2020;26:187-196.
   PubMed Google Scholar
2. Andersen PM, Abrahams S, Borasio GD, et al. EFNS guidelines on the clinical management of amyotrophic lateral sclerosis: revised report of an EFNS task force. Eur J Neurol. 2012;19(3):360-375. doi:10.1111/j.1468-1331.2011.03501.x
   Article PubMed Google Scholar
3. Zarei S, Carr K, Reiley L, et al. A comprehensive review of amyotrophic lateral sclerosis. Surg Neurol Int. 2015;6:171. doi:10.4103/2152-7806.169561
   Article PubMed Google Scholar
4. Abhinav K, Stanton B, Johnston C, et al. Amyotrophic lateral sclerosis in South-East England: a population-based study. Neuroepidemiology. 2007;29(1-2):44-48. doi:10.1159/000108917
   Article PubMed Google Scholar
5. Masrori P, Van Damme P. Amyotrophic lateral sclerosis: a clinical review. Eur J Neurol. 2020;27(10):1918-1929. doi:10.1111/ene.14393
   Article PubMed Google Scholar
6. Wijesekera LC, Leigh PN. Amyotrophic lateral sclerosis. Orphanet J Rare Dis. 2009;4:3. doi:10.1186/1750-1172-4-3
   Article PubMed Google Scholar
7. Hartmaier SL, Rhodes T, Cook SF, et al. Qualitative measures that assess functional disability and quality of life in ALS. Health Qual Life Outcomes. 2022;20(1):12. doi:10.1186/s12955-022-01919-9
   Article PubMed Google Scholar
8. Costa DSJ, Mercieca-Bebber R, Rutherford C, Tait MA, King MT. How is quality of life defined and assessed in published research? Qual Life Res. 2021;30(8):2109-2121. doi:10.1007/s11136-021-02826-0
   Article PubMed Google Scholar
9. Üstün TB, Chatterji S, Bickenbach J, Kostanjsek N, Schneider M. The International Classification of Functioning, Disability and Health: a new tool for understanding disability and health. Disabil Rehabil. 2003;25(11-12):565-571.
   PubMed Google Scholar
10. Beninato M, Portney LG, Sullivan PE. Using the International Classification of Functioning, Disability and Health as a framework to examine the association between falls and clinical assessment tools in people with stroke. Phys Ther. 2009;89(8):816-825. doi:10.2522/ptj.20080160
    Article PubMed Google Scholar
11. Hoare B, Imms C, Randall M, Carey L. Linking cerebral palsy upper limb measures to the International Classification of Functioning, Disability and Health. J Rehabil Med. 2011;43(11):987-996. doi:10.2340/16501977-0886
    Article PubMed Google Scholar
12. Raggi A, Leonardi M. Assessing activity limitations in patients with neuromuscular diseases: is the ACTIVLIM questionnaire linked to ICF and ICF-CY? Int J Rehabil Res. 2009;32(2):148-153. doi:10.1097/mrr.0b013e32831e4573
    Article PubMed Google Scholar
13. Raggi A, Quintas R, Russo E, et al. Mapping SAGE questionnaire to the International Classification of Functioning, Disability and Health. Clin Psychol Psychother. 2014;21(3):199-203. doi:10.1002/cpp.1857
    Article PubMed Google Scholar
14. Jenkinson C, Harris R, Fitzpatrick R. The Amyotrophic Lateral Sclerosis Assessment Questionnaire: evidence for a method of imputing missing data. Amyotroph Lateral Scler. 2007;8(2):90-95. doi:10.1080/17482960600989343
    Article PubMed Google Scholar
15. Jenkinson C, Fitzpatrick R. Reduced item set for the Amyotrophic Lateral Sclerosis Assessment Questionnaire: development and validation of the ALSAQ-5. J Neurol Neurosurg Psychiatry. 2001;70(1):70-73. doi:10.1136/jnnp.70.1.70
    Article PubMed Google Scholar
16. Simmons Z, Felgoise SH, Bremer BA, et al. The ALSSQOL: balancing physical and nonphysical factors in assessing quality of life in ALS. Neurology. 2006;67(9):1659-1664. doi:10.1212/01.wnl.0000242887.79115.19
    Article PubMed Google Scholar
17. Felgoise SH, Feinberg R, Stephens HE, et al. Amyotrophic lateral sclerosis-specific quality of life-short form: a brief, reliable, and valid version of the ALSSQOL-R. Muscle Nerve. 2018;58(5):646-654. doi:10.1002/mus.26203
    Article PubMed Google Scholar
18. Cieza A, Fayed N, Bickenbach J, Prodinger B. Refinements of the ICF Linking Rules to strengthen their potential for establishing comparability of health information. Disabil Rehabil. 2019;41(5):574-583. doi:10.3109/09638288.2016.1145258
    Article PubMed Google Scholar
19. Brennan PF, Hays BJ. Focus on psychometrics: the kappa statistic for establishing interrater reliability in the secondary analysis of qualitative clinical data. Res Nurs Health. 1992;15(2):153-158. doi:10.1002/nur.4770150210
    Article PubMed Google Scholar
20. Simmons Z. Patient-perceived outcomes and quality of life in ALS. Neurotherapeutics. 2015;12(2):394-402. doi:10.1007/s13311-014-0322-x
    Article PubMed Google Scholar
21. Bernardelli RS, Santos BC, Scharan KO, Corrêa KP, Silveira MIB, Moser ADL. Application of the refinements of ICF Linking Rules to the Visual Analogue Scale, Roland Morris questionnaire, and SF-36. Cien Saude Colet. 2021;26(3):1137-1152.
    PubMed Google Scholar
22. Prodinger B, Cieza A, Williams DA, et al. Measuring health in patients with fibromyalgia: content comparison of questionnaires based on the International Classification of Functioning, Disability and Health. Arthritis Rheum. 2008;59(5):650-658. doi:10.1002/art.23559
    Article PubMed Google Scholar
23. Geyh S, Cieza A, Kollerits B, Grimby G, Stucki G. Content comparison of health-related quality of life measures used in stroke based on the International Classification of Functioning, Disability and Health: a systematic review. Qual Life Res. 2007;16(5):833-851. doi:10.1007/s11136-007-9174-8
    Article PubMed Google Scholar
24. Cieza A, Stucki G. Content comparison of health-related quality of life instruments based on the International Classification of Functioning, Disability and Health. Qual Life Res. 2005;14(5):1225-1237. doi:10.1007/s11136-004-4773-0
    Article PubMed Google Scholar
25. Ballert CS, Hopfe M, Kus S, Mader L, Prodinger B. Using the refined ICF Linking Rules to compare the content of existing instruments and assessments: a systematic review and exemplary analysis of instruments measuring participation. Disabil Rehabil. 2019;41(5):584-600. doi:10.1080/09638288.2016.1198433
    Article PubMed Google Scholar

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About This Article

Received:

December 29, 2023

Accepted:

February 29, 2024

Published Online:

March 9, 2024

Printed:

April 1, 2024