Psychometrická validácia dotazníka MSQOL-54 na Slovensku – pilotná štúdia

Overview

Aim: Multiple sclerosis has a major impact on the quality of life of the patient. The aim of the study was to validate the Multiple Sclerosis Quality of Life Questionnaire – 54 (MSQOL-54) linguistically and culturally. The instrument includes a wide range domain of quality of life which is related with health. Methodology: Principal component analysis with orthogonal Varimax rotation was used to assess the construct validity. Preliminary analysis was performed using the Kaiser Meyer-Olkin statistic and Bartlett‘s test of sphericity. For the analysis of the factor structure of the instrument we used the procedures of confirmatory factor analysis. Results: In the pilot study there were 104 respondents. The reliability of the whole questionnaire confirmed the value of Cronbach a = 0.979. The most significant correlations were found between the Expanded Disability Status Scale scores: pain and physical health (P < 0.001). Statistically significant inverse correlations were found between duration of disease and MSQoL-54 subscales at the P < 0.001 level in the areas: task limitation due to emotional problems, energy, cognitive functions, sexual activity, change in health status, and satisfaction with sexual activity. Conclusion: The questionnaire shows possibilities of use in a larger sample of respondents without limitation to the dia­gnosed type of multiple sclerosis and with extended items in the area of sociodemographic screening, level of self-care and mental health.

Keywords:

Quality of life – Reliability – validity – sclerosis multiplex – questionnaire MSQOL-54

This is an unauthorised machine translation into English made using the DeepL Translate Pro translator. The editors do not guarantee that the content of the article corresponds fully to the original language version.

 

Introduction

Sclerosis multiplex (SM) is a chronic disease characterized by the pathological presence of inflammatory foci in the white matter in different regions of the CNS, demyelination and glial scar formation. A key diagnostic and prognostic phenomenon is the dissemination of these foci in different CNS localisations and at different time points in life. The course of the disease is characterized by alternating attacks and remissions with progressive deterioration of health status [1]. As the disease progresses, the patient becomes disabled and loses self-sufficiency in daily activities, which arouses feelings of hopelessness. The disease has a negative impact on the individual, on the socioeconomic and emotional spheres, as well as on family members and society, which requires psychosocial approaches in addition to therapeutic interventions to help overcome the problems associated with the disease and its progression [2,3].

The disease itself has a significant impact on the patient's quality of life. The concept of quality of life encompasses dimensions of physical and mental health. It is clearly multidimensional in nature and affects different areas of an individual's personality. It is consistent with the broadly defined focus of nursing, midwifery and other health sciences, using knowledge not only from the medical but also from the humanities, which ultimately extend in their complexity into the social, educational and educational spheres. The knowledge from the aforementioned disciplines enables a comprehensive view of the human being in his bio-psycho-social unity in the context of pedagogy, psychology, sociology, as well as the participation of other disciplines [2,4]. In clinical practice, we encounter the fact that the current state of quality of life assessment in patients with SM is characterized by considerable inconsistency and numerous differentiations in the use of assessment tools [5,6].

Clinical practice, demographic changes in terms of ageing population, increase in polymorbidity and chronicity of diseases, the need to take into account the needs of the individual and a holistic view of the individual require the use of specific questionnaires that monitor the patient's quality of life in addition to his/her health status [7].

When choosing an adequate quality of life measurement tool, it is necessary to pay attention to the needs of the individual or the whole community, and it is essential to take into account the specifics of the disease currently present. It is important to use a valid and reliable, standardized, culturally sensitive instrument in the language in which it will be used, that it is appropriate in scope, and that the author has permission, the necessary consent of the organization that holds the copyright, to use a particular instrument [5,7].

Questionnaires are frequently used to monitor quality of life, health status and are presented in three forms: global assessment questionnaires, generic questionnaires, specific questionnaires [8].

Generic questionnaires, designed exclusively for clinical practice, also suitable for patients with neurological diseases include:

           The Short Form-36 (SF-36) is a self-assessment tool for Health Related Quality of Life (HRQOL) [9]. It captures a large number of factors that affect the health of patients with SM.

    The Sickness Impact Profile (SIP) is a generic questionnaire designed to assess health-related functional status, across demographically and culturally diverse groups suffering from different types of illness. Its results are used to create a descriptive model of changes in patient behaviour in relation to their illness. It is mainly used in health research, programme design and monitoring of patient (disease) progression [10].

    The Nottingham Health Profile (NHP) was created in the 1970s to measure the impact of disease on the patient and to assess changes in health, over time [7,10].

    The Medical Outcomes Study 12-Item Short Form (SF-12) is an instrument that includes general health-related concepts but is not specific to any disease or type of treatment; it contains 12 items (the longer version, the SF-36, has 36 items) and focuses on physical health and mental health. The instrument has been translated, validated and standardised in more than 15 countries worldwide. It is very often included among the most widely used quality-of-life instruments for patients for this very reason [5,7].

 

Specific questionnaires are designed for a particular subgroup or disease/injury, allowing assessment of health status trends over time, while being sensitive to sometimes small but clinically significant changes in health status. They take into account a narrower range of factors that are closely linked to a specific disease. The tools achieve greater measurement sensitivity and show greater discriminant validity compared to generic tools [11].

The current state of quality of life assessment in patients with SM is characterized by considerable inconsistency and numerous differentiations in the use of assessment tools [6]. Among the disease-specific questionnaires for SM we include [7] Multiple Sclerosis Quality of Life Questionnaire (MSQOL-54), Multiple Sclerosis International Quality of Life questionnaire (MusiQOL), Functional Assessment of Multiple Sclerosis (FAMS), Functional Index for Living with Multiple Sclerosis (FILMS), Hamburg Quality of Life Questionnaire in Multiple Sclerosis (HAQUAMS), Leeds Multiple Sclerosis Quality of Life scale (LMSQoL), Needs-focused tools Patient-reported outcome indices for multiple sclerosis (PRIMUS), Services and Unmet Needs (SUN), Multiple Sclerosis Functional Composite (MFSC), Multiple Sclerosis Walking Scale - 12 (MSWS--12), Multiple Sclerosis Questionnaire for Job Difficulties (MSQ-Job), Multiple Sclerosis Fatigue Self Efficacy scale, Multiple Sclerosis Impact Scale (MSIS-29) [12].

Currently, no validated version of a specific measurement tool for the assessment of quality of life of patients with SM is available in clinical practice in Slovakia. This overall reduces the ability to monitor changes in individual areas of patients' quality of life and the impact of the disease on the patient and his/her close social environment. Therefore, the main aim of our study was to linguistically and culturally validate the MSQOL-54 questionnaire in Slovak language and to determine whether this instrument is suitable for assessing the quality of life of MS patients in Slovakia.

On the basis of consultations and cooperation with the author of the questionnaire, prof. Vickrey and the educational institution - the University of California, Los Angeles, clinical experts at the University Hospital with Polyclinic J. A. Reiman Hospital in Prešov, with experts of St. James Hospital, n.o. in Bardejov, selected neurological outpatient clinics of the Prešov and Košice regions and certified translation agencies, the methodological preparation of the research was carried out with regard to obtaining the author's consent for the use of the selected MSQOL--54 questionnaire, certified back-translation of the questionnaire and identification of the research population.

The process of implementing the linguistic-cultural adaptation of the MSQOL-54 questionnaire was carried out in the following stages:

1. translation of the questionnaire into the target language;

2.
Synthesis, adaptation and resolution of discrepancies within language and culture;

3.
back translation of the Slovak version into English;

4.
Evaluation by a committee of experts- physician, methodologist, researcher, language professional, to reach consensus and develop a pre-final version;

5.
A pilot study on a selected sample of patients with its evaluation and necessary correction for a preliminary assessment of the psychometric properties of the questionnaire.

 

Subjects and methods

A pilot study to validate the MSQoL-54 questionnaire

Patients with an established diagnosis of SM were enrolled in the pilot study. All of them were treated at the University Hospital with Polyclinic J. A. Reiman Hospital in Prešov and St. James Hospital with Polyclinic in Bardejov in the period from January 2021 to May 2021.

The inclusion criteria for the pilot study were as follows:

           over 18 years of age;

    diagnosed with SM relapsing/remitting form according to McDonald criteria [13];

    written informed consent for inclusion in the study.

 

Exclusion criteria for respondents included:

               exacerbation of SM disease in the last month;

    existing other chronic illness and/or psychiatric disorders.

 

In this pilot study, we used the already translated and culturally adapted MSQoL-54 questionnaire into Slovak language for the Slovak population of SM patients. The MSQoL-54 questionnaire was completed by the patients in the presence of a nurse who could help with any problems with understanding the questions and technicalities of completing the questionnaire. The patient's disability was assessed by a neurologist using the Expanded Disability Status Scale (EDSS).

Acceptance of the questionnaire was assessed by the mean time to complete the questionnaire (recommended administration time 11-18 min [14]), the percentage of missing data, and the help patients needed in terms of reading, writing or explaining the questionnaire items.

MSQoL-54 scale scores were generated by the Likert method by averaging the items within the scales, and the subsequent scores were linearly transformed on a scale from 0 to 100 according to the recommended questionnaire scoring methodology [14]. Whereby higher values across items and domains indicate better quality of life.

The internal reliability of the Slovak version of the MSQoL-54 was assessed for multi-item scales using Cronbach's alpha coefficients ranging from 0 to 1, where 1 indicates perfect reliability. Clinical validity was assessed by comparing the means of two MSQoL-54 summary scores according to the EDSS scores. Pearson's correlation coefficient (r) was used to examine the relationship between the summary score and the main clinical and demographic variables.

Characteristics of the research population

104 respondents participated in the pilot study. The characteristics of the research sample in terms of demographic characteristics are presented in Table 1.

 

Characteristics of the MSQOL-54 questionnaire

The MSQOL-54 questionnaire was originally developed for English-speaking SM patients and consists of two parts. The first part consists of questions assessing general health based on the SF-36 questionnaire. The second part is made up of eighteen questions specifically designed for the needs of SM patients and based on expert opinion and literature search. Fifty-four questions are divided into 12 subscales. They collect data on the respondents' physical, mental and emotional health, cognitive abilities, social activities, limitations resulting from physical and affective indicators, pain intensity, fatigue, energy, and the respondents' sex life. The questionnaire also includes questions on subjective perception of health, level of health burden and quality of life. Given its multidimensional and content focus, their validation and incorporation into clinical practice is desirable. The validation process of the questionnaire was carried out in consultation with the main and responsible author of the questionnaire, prof. Barbara Vickrey from the University of California, Los Angeles, USA.

One of the most commonly used tools in the world for measuring and assessing the quality of life of patients with SM is the MSQOL-54 construct [15,16]. The instrument was originally developed in the USA in 1995 [14], and has since been transculturally adapted. In the past, the instrument has been culturally validated in many languages (Italian, Turkish, Bosnian, Serbian, Slovenian, Hungarian, Indonesian as well as for the needs of Canadian French) in an attempt to overcome the language barrier in implementing the instrument in clinical practice [17-19]. Overall, the above tool has good internal consistency. The result of this questionnaire reflects physical and mental health status in the form of a composite physical and mental health score, respectively [17-19]. The detailed characteristics of the MSQOL54 instrument are presented in Table 2.

The time required to complete the questionnaire is approximately 11-18 min. The MSQOL-54 questionnaire is a structured questionnaire that each individual completes usually with little or no assistance. Patients with visual impairment or upper limb impairment may exhibit a need for the MSQOL-54 questionnaire to be presented in the form of an interview. Staff (health professionals, researchers) who conduct interviews of this type should be trained in basic interviewing skills and in the use of this tool [15,16].

The MSQOL-54 is easy to administer, covers a wide range of health-related quality of life domains, and includes one of the most widely used quality of life measures for SM. The availability of population-based normative data for the SF-36 section of the MSQOL-54 makes this tool useful for comparison opportunities. The availability of several subscales may be useful for researchers interested in testing hypotheses related to the domains listed above. Although the construct of the MSQOL-54 includes many components specific to issues such as fatigue, researchers may in the future expand the instrument to include other indicators that can assess these issues in greater depth, such as the Modified Fatigue Impact Scale (MFIS) questionnaire. In the SM patient population, the 12 subscales of the MSQOL-54 questionnaire show good internal consistency with Cronbach's alphas ranging from 0.75-0.96. Test-retest reliability for these 12 subscales shows good psychometric properties with intrasubject correlation coefficients in the range of 0.66-0.96. There is evidence for the validity of the MSQOL-54 questionnaire in the study by Vickrey et al. [14]. The physical function and role limitation subscales showed the most significant difference between SM patients and the normative US population. The MSQOL-54 also demonstrated a significant association with severity of SM symptoms during the previous year, level of mobility, limitations in employment due to health problems, and hospitalizations during the previous year. The good psychometric properties of the instrument are confirmed by studies [13,17,19-22]. Even the shortened version of the MSQoL-29 questionnaire showed satisfactory psychometric properties in the study by Rosato et al [23].

 

Characteristics of statistical procedures

Internal consistency was used to assess the reliability of the instrument, assessed by calculating Cronbach's alpha (a ), which should range from 0 to 1, the latter indicating perfect internal consistency. An instrument is considered internally consistent ifa ≥ 0.70.

In order to assess the construct validity and dimensionality of the tool, Principal Component Analysis (PCA) with orthogonal Varimax rotation was planned to be used. Preliminary analysis regarding data screening, hypothesis testing and selection adequacy was performed using Kaiser Meyer-Olkin (KMO) statistics with respective values > 0.5 and Bartlett's test of sphericity with p ≤ 0.05. Results were processed using the SPSS 21 statistical software (IBM, Armonk, NY, USA) and in the R programming environment using the lavaan [24] and semTools [25] libraries.

For the purpose of factor structure analysis of the MSQOL-54 instrument, we used confirmatory factor analysis procedures. Given the ordinal nature of the MSQOL-54 items, we assessed the fit of the tested model to the data based on a matrix of polychoric correlations using the weighted least square mean and variance (WLSVM) [26,27], chi-square statistical method, following the overall fit indices with the optimal values: (%2/df < 2, RMSEA < 0.08, TLI > 0.90, CFI > 0.90, SRMR < 0.08), and sub-indices (statistical significance of model parameters) [28].

Descriptive statistics (frequency, percentage, mean and standard deviation) were used to analyse socio-demographic indicators and other characteristics of the study population. To detect the existence of a significant difference between two independent groups, we used the Mann-Whitney U test. Pearson correlations were used to determine statistically significant relationships between variables in the study.

 

Results

Analysis of questionnaire acceptance

The mean time to complete the questionnaire in the pilot study was 16.2 ± 9.2 min. The majority of participating patients (93%) did not need additional explanation of the submitted items. Only 7% of the patients needed help from another person to read and write due to visual difficulties or upper limb disability. From the analysis of the data, we conclude that all respondents completed the submitted questionnaire 100% of the time, with no items missing from any questionnaire.

 

Results of the psychometric validation of the MSQoL-54 questionnaire - pilot study

Reliability of the MSQoL-54 questionnaire

In general, this study found a high reliability value, confirming the fact that this questionnaire is internally consistent. Our validated questionnaire for the Slovak population shows a significant degree of reliability through Cronbach's alpha, as the individual subscales of the questionnaire achieve Cronbach's alpha in the range of 0.78-0.97. The results of the reliability analysis of the whole questionnaire confirmed the value of Cronbacha = 0.979, which represents a very high reliability value of the questionnaire The results of the reliability analysis of the MSQOL-54 questionnaire are presented in Table 3.

 

Construct validity of the MSQOL-54

In order to assess the construct validity - dimensionality of the instrument, PCA was planned to be used on 12 subscales of the instrument with orthogonal Varimax rotation. Preliminary analysis regarding data screening, hypothesis testing and selection adequacy was performed using KMO statistics with respective values > 0.5 and Bartlett's test of sphericity with p ≤ 0.05. The KMO test and Bartlett's test were found to be statistically acceptable (> 0.5) for subsequent use of PCA.

The PCA results showed that only the first two components had eigenvalues greater than 1, accounting for 59.4% of the total variance. Hence, only these two components were retained in the analysis. Table 4 shows the component after rotation.

Subscales such as emotional well-being, cognitive function, energy, health difficulties, limitations due to emotional reasons, and pain were related to the mental dimension of the MSQOL-54 instrument and highly correlated with component 2, mental health, suggesting that this component is in fact a mental component. Physical health, role limitation due to physical problems, and social and sexual functioning were subscales that correlated with the physical dimension of the MSQOL-54 and were related to Component 1 - physical health.

The energy subscale (originally a subscale in the physical health component) also showed a high mental health burden. Pain, perceived health, and overall quality of life were the only subscales that loaded about equally on both components. The factor loadings of the Varimax questionnaire are presented in Table 1. 5.

The MSQOL-54 scales met standard psychometric norms. Within-scales coefficients were homogeneous and scored above 0.40 in most cases (indicating good convergent validity). Larger correlations (when analyzing individual scales) were found within scales than between scales (indicating good discriminant validity).

In Table 6, we present how respondents globally rated each subscale of the questionnaire. Our respondents in our study group rated the physical health domain most highly. They rated the physical health subscale with an average score of 57.25; with 100 being the most optimal rating. The second area that respondents scored best was pain, with a mean value of 62.24. The third subscale that respondents scored best was social functioning, with a mean value of 62.58. Cognitive functions were very well scored by the respondents, with an average score of 57.93.

Areas that scored reasonably well included: sexual activity (mean score was 56.89) and changes in health (mean score was 56.58). Emotional well-being scored a mean of 52.9.

The worst rated area was task limitations due to physical problems, with an average of 35.34 points. The second area rated worst by respondents was the area of energy (mean value 42.70). The third area that was scored worst was overall quality of life, which had a mean value of 42.75. One of the areas that scored worse was satisfaction with sexual activity, which had a mean score of 49.54.

Statistically significant inverse (negative) correlations were found between EDSS scores and all subscales of the MSQoL--54 questionnaire (Table 4). The most significant correlations were found between EDSS scores: pain and physical health (p < 0.001). Correlations at the p < 0.01 level were demonstrated in the domains: role limitation due to physical problems, role limitation due to emotional problems, emotional support, energy, social function, cognitive function, satisfaction with sexual activity, and overall quality of life.

Statistically significant inverse (negative) correlations were found between disease duration and MSQoL-54 subscales at the p < 0.001 level in the domains: task limitation due to emotional problems, energy, cognitive function, sexual activity, change in health status, satisfaction with sexual activity. Correlations at the p < 0.05 level were demonstrated in the subscales of physical health, social function, health difficulties, and at the p < 0.05 level in the domain of overall quality of life (Table 7).

In terms of social needs, we looked at the relationship between social support and employment. We used the Mann-Whitney U test to determine whether there was a significant difference between the two independent groups. In Table 8, we present a comparison of the statistics of all subscales, comparing the group of employed (n = 67) and unemployed (n = 37) respondents. In almost all items, employed respondents showed better values for perceived quality of life. Respondents gave us worse values in the following areas: pain, cognitive function, and overall quality of life.

 

Discussion

The Slovak MSQOL-54 questionnaire was well accepted by our SM patients in the pilot study, with 93% of them having no problem completing the questionnaire independently. This result does not differ from those obtained from American (USA), Italian, Turkish and Serbian patients with SM [16-19]. Only 7% of our patients in our research needed help and assistance from nurses to complete the questionnaire due to visual or fine motor impairment after previous impairment of upper limb function.

In our pilot study of 104 respondents, all items were 100% completed and there were no missing items. In the other validation studies, a small number of patients were present in whom questions related to sexual function and satisfaction with sexual function caused inconvenience in completing the questionnaire. The majority of missing item responses in these validation studies were accounted for by these subscales. In previously published studies with similar issues, these items were the main source of missing data. The mean time to complete the questionnaire was 16.2 ± 9.2 min, indicating that this was not a difficult task for the patients and confirming the fact that the questionnaire was easy to understand. Similar results have been found in other studies where the mean time to complete the MSQOL-54 ranged from 11.8-30 min [16-19].

The internal consistency of the questionnaire in line with our results is satisfactory according to the set criteria and other currently conducted validation studies. The EDSS scores in our study showed a significant negative correlation with all dimensions of health status in the MSQoL-54 subscales. These correlations are similar to the results of validation studies conducted previously [17-19].

Composite physical health and Composite mental health also showed significant correlations with EDSS. A Serbian validation study found that these domains were significantly correlated with patient age, education, and occupation [16]. The Hungarian validation study reported that the group of patients who had lower EDSS performed better in HRQOL scores in each scale. Solari et al also found a high correlation between both composite scores and age [18].

Our pilot study focused on patients with SM (diagnosed with relapsing/remitting SM according to the McDonald criteria), and included baseline sociodemographic data (gender, disease duration, and occupation) to examine variables that affect quality of life. We found only small significant differences in the comparisons between the two sexes in the male and female comparison groups. In terms of the variables: duration of illness and employment, we found a higher degree of burden for respondents in the quality of life assessment with duration of SM and unemployment.

 

Conclusion

The presented study fulfilled the sub-objective to conduct a pilot study of the validation of the MSQOL-54 questionnaire to determine the psychometric properties of the measurement instrument in the Slovak population. In the present study, we validated the psychometric properties and confirmed sufficient criterion and construct validity of the Slovak version of the MSQOL-54. The assessment of individual domains of quality of life allows a better understanding of how the disease and its treatment are realistically reflected in the daily life of a patient with MS. It also helps to better understand preferences, expectations and demands in relation to the disease. These findings can be used in clinical practice to provide ongoing and follow-up care, as well as to improve patient adherence and self-care in the context of a comprehensive therapeutic regimen.

The validated questionnaire, through a pilot study, demonstrates the potential for its use with a larger sample of respondents without restriction to the type of SM diagnosed and with expanded items in the areas of sociodemographic screening, level of self-care, and mental health. The size of the sample in the final validation study will match the sample size requirements. For criterion and convergent quality in relation to the number of instrument items, a minimum of 10 respondents per 1 item of the domain variable of interest (pilot study 104 respondents, final validation study 280 respondents).

Due to the cross-sectional design of the study, longitudinal validity could not be observed. Thus, further research to test the sensitivity of the questionnaire to change needs to be conducted in the future. That is, the ability of the instrument to detect clinically significant change over time. Another limitation was patient selection. Only patients without cognitive deficits were included in the study. Also, patients whose quality of life would be affected by a recent seizure within a month, or other serious chronic, physical or psychological illness, were not included in the study.

Standardized quality of life assessment is needed in clinical practice for objective and reliable assessment of the consequences of SM disease. Information obtained in this way enables objective and adequate assessment and evaluation of quality of life in the provision of multidisciplinary care and identification of all aspects and consequences of disability due to the disease.

 

Ethical principles

The work was carried out in compliance with the Helsinki Declaration of 1975 and its revisions in 2004 and 2008. The study was approved by the local ethics committee of the Department of Health, Ethics Committee, Prešov Self-Governing Region: the office of the PSK, Námestie mieru 2; 080 01 Prešov, on: 21.10.2021, under the number: 03215/2021/OZ-40. The study was carried out after the ethical approval of the Ethics Committee of the University Hospital with Polyclinic J. A. Reiman in Prešov, Hospital with Polyclinic of St. James, n.o. in Bardejov, and on the basis of the consent granted by the President of the self-governing region as the founder of selected neurological outpatient clinics of the Prešov self-governing region.All patients signed an informed consent to participate in the study.

 

Grant support

This paper was published in the framework of the KEGA grant project: 002PU-4/2020 Design of a methodology for the assessment of quality of life in patients with sclerosis multiplex.

 

Conflict of interest

The authors declare no conflict of interest in relation to the present study.

 

Tables

Table 1: Characteristics of respondents.

Demographic data	n	%
Gender man Woman	20 84	19 81
Education Basic secondary education without matriculation secondary education with a secondary school leaving certificate College	0 16 53 35	0 15 51 35
Age (M ± SD) 20-29 years old 30-39 years old 40-49 years old 50-59 years old 60-65 years old	40,5 ± 10,83 years 18 36 28 15 7	min-max: 20-65 17 35 27 14 7
Disease duration (M ± SD) 1-4 years 5-9 years 10-14 years 15-20 years 21-25 years old	7.8 ± 6.93 years 53 19 15 10 7	min-max: 1-25 50 19 14 10 7
Type of treatment Immunomodulatory without treatment	85 19	81 18
EDSS	4,51 ± 2,21	min-max: 1.0-8.0
Employment jobs Unemployed	67 37	65 35

EDSS - Expanded Disability Status Scale; M - mean; Max - maximum value; Min - minimum value; n - number; SD - standard deviation

 

 

Table 2. Research instrument MSQOL54. Modified from .[14]

MSQOL-54
General information	Subscales	Evaluation method
The first multidimensional specific instrument to measure quality of life in multiple sclerosis patients focusing on health status and activities of daily living, it is based on the generic SF-36 rating scale augmented with 18 added specific items specifically aimed at managing typical clinical symptoms	54 items, 12 physical functions (10) physical role limitation (4) psychological role limitation (3) pain (2) emotional well-being (5) energy (4) perception of health (5) social function (2) cognitive function (4) health problems (4) overall quality of life (2) sexual function (4)	3, 4, 5, 6 or 7 level Likert scale Physical and mental health are assessed separately, creating two summary scores. The total score is calculated as the average of all items using three tables. At the end, all the summary scores are added together to produce a final score for the entire questionnaire. A higher total score determines a higher quality of life; the range of the final score is from 0 to 100 points.

MSQOL54 - Multiple Sclerosis Quality of Life Questionnaire; SF - Short Form

 

 

 

Table 3. Results of the reliability analysis of the MSQoL-54 questionnaire for each subscale.

	n	Number of items	Cronbach's Alpha	Cronbach alpha Vicrey et al. (1995)
physical health	104	10	0,959	0,96
task limitations due to physical problems	104	4	0,962	0,86
task limitations due to emotional problems	104	4	0,833	0,84
Pain	104	3	0,967	0,92
emotional well-being	104	5	0,836	0,87
energy	104	5	0,893	0,84
perception of health	104	5	0,856
social functions	104	3	0,857	0,75
cognitive function	104	4	0,783	0,90
health problems	104	4	0,921	0,91
sexual activity	104	4	0,933	0,85
change in health	104	1	-	-
satisfaction with sexual activity	104	1	-	-
overall quality of life	104	2	0,972	0,86
total score	104	54	0,979	-

MSQOL54 - Multiple Sclerosis Quality of Life Questionnaire; n - number

 

 

 

Table 4. Results of MSQoL-54 and EDSS correlations (Pearson correlations).

	n	r	p
Physical health	104	-0,675	***
Task limitations due to physical problems	104	-0,422	**
Task limitations due to emotional problems	104	-0,375	**
Pain	104	-0,746	***
Emotional well-being	104	-0,340	**
Energy	104	-0,426	**
Perception of health	104	-0,201	*
Social functions	104	-0,327	**
Cognitive function	104	-0,376	**
Health difficulties	104	-0,242	*
Sexual activity	104	-0,252	*
Change in health status	104	-0,219	*
Satisfaction with sexual activity	104	-0,377	**
Overall quality of life	104	-0,301	**
Physical composite score	104	-0,387	**
Mental composite score	104	-0,311	**

*p < 0.05; **p < 0.01; ***p < 0.001

EDSS - Expanded Disability Status Scale; MSQOL54 - Multiple Sclerosis Quality of Life Questionnaire; n - number

 

 

Table 5: Factor loading of the questionnaire (Varimax method).

Variable
	Factor 1 Physical health	Factor 2 Mental health
physical health	0,949***	0,132
task limitations due to physical problems	0,704***	0,352*
task limitations due to emotional problems	0,216	0,658**
Pain	0,580***	0,607**
emotional well-being	0,159	0,841***
energy	0,391*	0,754***
perception of health	0,546***	0,537***
social functions	0,733***	0,428**
cognitive function	0,028	0,792***
health problems	0,469**	0,627**
sexual activity	0,479**	0,354*
change in health	0,478**	0,339*
satisfaction with sexual activity	0,365*	0,229
overall quality of life	0,503***	0,512***

Factor weight significance level:  > |0.3| significant*; > |0.4| moderately significant**; > |0.5| highly significant***.

 

 

Table 6: Evaluation of the entire sample of respondents (n = 104).

	M	SD	Min-max
physical health	57,25	53,1	0-50
task limitations due to physical problems	35,34	41,17	0-100
task limitations due to emotional problems	50	48,15	0-100
Pain	62,24	61,90	0-100
emotional well-being	52,9	57,60	4-100
energy	42,70	53,21	0-100
perception of health	48,30	20,01	10-90
social functions	62,58	21,1	8-100
cognitive function	57,93	19,76	5-100
health problems	53,84	24,58	0-100
sexual activity	56,89	22,64	0-100
change in health	56,58	25,8	5-100
satisfaction with sexual activity	49,54	21,1	0-100
overall quality of life	42,75	19,76	0-100
physical composite score	52,14	15,05	-
psychological composite score	51,16	15,58	-

M - mean; max - maximum value; min - minimum value; n - number; SD - standard deviation

 

 

 

Table 7: Results of correlations between MSQoL-54 and disease duration (Pearson correlations).

	n	r	p
physical health	104	-0,295	*
task limitations due to physical problems	104	-0,181
task limitations due to emotional problems	104	-0,530	***
Pain	104	-0,003
emotional well-being	104	-0,106
energy	104	-0,706	***
perception of health	104	-0,021
social functions	104	-0,220	*
cognitive function	104	-0,848	***
health problems	104	-0,195	*
sexual activity	104	-0,754	***
change in health	104	-0,625	***
satisfaction with sexual activity	104	-0,569	***
overall quality of life	104	-0,542	**

*p < 0.05; **p < 0.01; ***p < 0.001

MSQOL54 - Multiple Sclerosis Quality of Life Questionnaire; n - number

 

 

 

Table 8: Comparison of quality of life in terms of employment.

	employed (n = 67)		unemployed (n = 37)
	M	SD	M	SD	p
physical health	69,17	26,1	35,67	27,3	0,90
task limitations due to physical problems	43,66	41,14	20,27	35,76	0,004*
task limitations due to emotional problems	60,20	39,02	31,53	43,71	0,0008**
Pain	65,62	27,73	56,13	30,88	0,112
emotional well-being	56,20	19,53	47,13	18,88	0,025*
energy	45,13	21,49	36,81	19,12	0,052
perception of health	50,97	19,56	42,70	20,22	0,044*
social functions	69,03	21,06	50,90	23,55	0,0001***
cognitive function	59,18	27,13	55,68	25,74	0,522
health problems	57,61	26,09	47,03	24,11	0,044*
overall quality of life	45,89	22,2	37,8	24,3	0,224

*p < 0.05; **p < 0.01; ***p < 0.001

M - mean; n - number; SD - standard deviation