|Year : 2016 | Volume
| Issue : 3 | Page : 161-167
Self-reported quality of life of patients with multiple sclerosis with mild disability
Safeya Effat1, Hanan Azzam1, Ali Shalash2, Seham Elkatan1, Hanan Elrassas1
1 Department of Psychiatry, Faculty of Medicine, Ain Shams University, Cairo, Egypt
2 Department of Neurology, Faculty of Medicine, Ain Shams University, Cairo, Egypt
|Date of Submission||29-Dec-2015|
|Date of Acceptance||28-Apr-2016|
|Date of Web Publication||27-Oct-2016|
Department of Neurology, Faculty of medicine, Ain Shams University, Cairo 11757
Source of Support: None, Conflict of Interest: None
Background The quality of life (QoL) of the patient is a reflection of the severity of multiple sclerosis (MS) and predicts its prognosis; it is related to various factors that vary across cultures.
Objective The aim of the current study was to evaluate the QoL of ambulatory and mildly disabled patients with relapsing remitting multiple sclerosis (RRMS), and explore the related factors and cultural characteristics.
Patients and methods Sixty Egyptian patients with a definitive diagnosis of RRMS were recruited and assessed for disability using Expanded Disability Status Scale, their QoL using Multiple Sclerosis Quality of Life Inventory (MSQLI), and depression using the Beck Depression Inventory scale. Patients’ QoL was compared with that of 30 matched controls.
Results The QoL of MS patients was significantly impaired in all domains compared with that of controls (P<0.001), except for Social Functioning. Most of the physical components of the QoL were strongly correlated with Expanded Disability Status Scale, fatigue, and perceived cognitive impairment, and mental components were correlated with depression (P<0.001), fatigue, and perceived cognitive impairment. An overall 81% of MS patients had depression that correlated with disability (P=0.012) and fatigue (P=0.001), and correlated moderately with perceived cognitive impairment. Women reported more anxiety (P=0.038) and less perceived social support (P=0.012), whereas men stated more sexual dissatisfaction (P=0.001).
Conclusion Mildly disabled Egyptian patients with RRMS have a high prevalence of depression and considerable impairment of mental and physical components of the QoL, such as disease disability, depression, fatigue, and perceived cognitive impairment.
Keywords: cognitive impairment, depression, fatigue, multiple sclerosis, quality of life
|How to cite this article:|
Effat S, Azzam H, Shalash A, Elkatan S, Elrassas H. Self-reported quality of life of patients with multiple sclerosis with mild disability. Egypt J Neurol Psychiatry Neurosurg 2016;53:161-7
|How to cite this URL:|
Effat S, Azzam H, Shalash A, Elkatan S, Elrassas H. Self-reported quality of life of patients with multiple sclerosis with mild disability. Egypt J Neurol Psychiatry Neurosurg [serial online] 2016 [cited 2021 Apr 19];53:161-7. Available from: http://www.ejnpn.eg.net/text.asp?2016/53/3/161/193066
| Introduction|| |
Multiple sclerosis (MS) is a chronic inflammatory disabling disease affecting young adults and impairs their quality of life (QoL) during their productive life . The QoL of MS patients has been ascertained by several studies in different countries and nations in order to reflect the disease outcome. Self-reported QoL assessment gives a comprehensive reflection of the patients’ disability and disease impact, guides physicians for proper care of MS patients, reflects treatment efficacy, and is considered a predictor of disease progression ,,. Depression and fatigue are the main determinants and predictors of health-related quality of life (HRQoL) among patients with relapsing remitting multiple sclerosis (RRMS) ,,. Although clinically significant depression affects up to 50% of MS patients and affects their QoL, it is often overlooked and undertreated by treating doctors .
Prior studies reported variability and differences in QoL impairment and its correlates across various cultures ,,. Recognizing depression, fatigue, and other psychosocial determinants of QoL in MS patients is highly important as those factors are modifiable and treatable . A few studies have examined the burden of the disease and its related factors in mildly disabled patients with RRMS .
In addition, a few studies have investigated QoL among MS patients in Arabic countries , but with limited information from Egypt. Thus, this study aimed to evaluate the QoL of ambulatory and mildly disabled Egyptian patients with RRMS, to determine its correlations, including disease disability, depression, and fatigue, and explore the characteristic cultural differences.
| Patients and methods|| |
Sixty Egyptian patients with a definitive diagnosis of RRMS were included in this cross-sectional study. Patients were recruited from outpatient clinics of the Gamal Abd-Elnaser Hospital (Alexandria, Egypt) and Ain Shams University Hospitals (Cairo, Egypt) during the period August 2011 to June 2012. Patients aged 18–60 years, diagnosed according to the 2005 revised McDonalds criteria, who were fully ambulant were included . Exclusion criteria included clinical relapse within 4 weeks, pregnancy, and history of associated medical illness or substance abuse (comorbidity).
All patients underwent full medical history (including clinical course and educational status), neurological assessment for ascertainment of the evolution of disease severity and related physical disability using the Expanded Disability Status Scale (EDSS) and its Functional System Score  by a neurologist, and MRI. EDSS quantifies neurological impairment and disability and ranges from 0 (normal) to 10 (death due to MS) according to disability scores of different functional systems (such as pyramidal, cerebellar, etc.) as well as walking impairment . Depression was assessed with the Beck Depression Inventory (BDI) , a widely used scale among neurological diseases that measures the symptoms and traits related to depression and has suggested cutoff values for mild, moderate, and severe depression and for absence of depression .
The QoL of MS patients was evaluated using the Multiple Sclerosis Quality of Life Inventory (MSQLI) . MSQLI is a widely adopted measure of HRQoL for patients with MS and has reliable and valid shortened subscales to decrease the administration time .
The following MSQLI subscales were included: Health Status Questionnaire [Short Form 36 (SF-36); 36 items, Arabic version] , a generic HRQoL measure, effectively detects differences in disease severity and includes eight subscales [Health Transition Item, Physical Functioning (PF), Role Physical (RP), Bodily Pain (BP), General Health (GH), Vitality (VT), Social Functioning (SF), Role Emotional (RE), and Mental Health (MH) scales]; higher scores reflect better health status. The physical components of SF-36 include PF, RP, BP, and GH scales, whereas mental components include VT, SF, RE, and MH scales. The Modified Fatigue Impact Scale (21 items) assesses the frequency and impact of fatigue on life; higher scores reflect more fatigue. The Pain Effects Scale (six items) assesses pain impact on patients’ mood and behavior; higher scores indicate greater impact. The Sexual Satisfaction Scale (five items) measures sexual function among married patients; higher scores indicate more dissatisfaction. The Bladder Control Scale (four items) evaluates bladder control and its impact. The Bowel Control Scale (five items) measures bowel control. The Impact of Visual Impairment Scale (five items) detects the impact of visual MS symptoms on patients’ visual activities. The Perceived Deficits Questionnaire (PDQ) (20 items) evaluates self-reported cognitive impairment; higher scores indicate greater cognitive dysfunction. The Mental Health Inventory (MHI) (18 items) assesses emotional/mental health status for MS patients and includes four subscales (anxiety subscale, depression subscale, behavior control subscale, positive affect subscale); higher scores indicate better mental health. Finally, the Modified Social Support Survey (18 items) is used as a measure of social support; higher scores reflect more perceived support. Higher scores for Bladder Control Scale, Bowel Control Scale, and Impact of Visual Impairment Scale indicate greater impairment and greater impact on patients’ life. Various scales were completed during the clinical interview and were administrated by the attending physician. Because of unavailability of normative values of SF-36 for the Egyptian population, physical and mental component summary scales could not be estimated and the SF-36 questionnaire was administrated to 30 matched healthy controls. The study was approved by the Ethical Committee of the Faculty of Medicine, Ain Shams University, in accordance with the ethical standards of the Declaration of Helsinki. Written informed consent was obtained from all recruited patients.
Data were fed into the computer using the Predictive Analytics Software (PASW Statistics 18, Chicago, USA). Qualitative data were described using number and percentage. Association between categorical variables was tested using the χ2-test. Quantitative data were described using mean and SD. The distributions of quantitative variables were tested for normality using the Kolmogorov–Smirnov test. Parametric tests were applied for normal data distribution. Otherwise, nonparametric tests were used. For normally distributed data, comparison between two independent populations was made using the independent t-test. Correlations between two quantitative variables were made using Pearson’s coefficient. The level of statistical significance (P-value) was set at 0.05 and 0.01.
| Results|| |
Ninety participants, 60 patients with fulfilled criteria for RRMS [32 (53%) women and 28 (46.7%) men] and 30 healthy controls (15 men and 15 women, of a mean age of 34.1±4.83 years) were included. The mean age of the MS patients was 35.47±6.17 years (range: 22–44 years) and duration of illness was 4.14±3.04 years. The mean disease disability was 2.40±0.82 and all patients had a score less than or equal to 4 (range: 0–4) [Table 1].
|Table 1: Demographic and clinical characteristic of multiple sclerosis patients|
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Using BDI, depression was detected in 49 (81%) patients. It was mild in 17 (28.3%), moderate in 11 (18.3%), and severe in 21 (35.1%) patients. All patients were of average socioeconomic status and educated. MRI in those patients showed that 57 (95%) patients had periventricular lesions, 16 (26.7%) patients had corpus callous lesions, 12 (20%) patients had infratentorial lesions, and 11 (18.3%) patients had spinal cord lesions. At the time of the study, 26 (43.3%) patients had received interferon β-1a as disease-modifying therapy, whereas 34 (56.7%) patients had received monthly methylprednisolone instead of unaffordable interferon β-1a. No patient had received antidepressants before recruitment. Further demographic and clinical criteria are illustrated in [Table 1].
Patients and healthy controls were matched for age, sex, and education level (P=0.254, 0.470, and 0.133, respectively). MS patients showed statistically highly significant impairment (lower scores) on all QoL subscales (P<0.001), moderate impairment on BP subscale (P=0.033), and nonsignificantly impaired SF (P=0.213), compared with controls [Figure 1].
|Figure 1: Short Form 36 domain scores for relapsing remitting multiple sclerosis patients and healthy controls. BP, Bodily Pain; GH, General Health; MH, Mental Health; MS, multiple sclerosis; PF, Physical Functioning; RE, Role Emotional; RP, Role Physical; SF, Social Functioning; VT, Vitality.|
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Correlates of health-related quality of life
PF item was negatively correlated with disease duration (r=−0.374, P=0.003), EDSS (r=−0.387, P=0.002) and with perceived cognitive impairment (r=−0.302, P=0.019), and RP was strongly negatively correlated with disease disability (r=−0.392, P=0.002) and global fatigue (r=−0.448, P<0.001), and negatively correlated with depression (r=−0.315, P=0.014) and perceived cognitive impairment (r=−0.286, P=0.027). BP was strongly negatively correlated with fatigue (r=−0.414, P=0.001), perceived cognitive impairment (strongly correlated, r=−0.370, P=0.004), and EDSS (r=−0.311, P=0.016), whereas GH had no significant correlations [Table 2]. Thus, better physical components of the QoL are related to shorter duration of illness, less motor disability, less perceived cognitive impairment, less fatigue severity, and less depression severity.
|Table 2: Correlation between clinical characteristics, depression, and different Multiple Sclerosis Quality of Life Inventory components among patients with ambulatory relapsing remitting multiple sclerosis|
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All mental components were negatively correlated with depression (poorer VT, r=−0.397, P=0.002; SF, r=−0.637, P<0.001; RE, r=−0.617, P<0.001; and MH, r=−0.519, P<0.001) and fatigue (VT, r=−0.361, P=0.005; SF, r=−0.323, P=0.012; and RE, r=−0.365, P=0.004; except MH). VT and MH were highly correlated with perceived cognitive impairment (P=0.04 and 0.026, respectively) and social support (P=0.009 and <0.001, respectively), whereas VT showed borderline correlation with EDSS (P=0.05) [Table 2]. In other words, the worse the depression, fatigue, perceived cognitive impairment, and social support, the poorer the mental QoL of MS patients.
Factors associated with disease disability, depression, fatigue, and cognitive impairment
Physical disease disability measured by EDSS was significantly correlated with fatigue (strongly correlated, r=0.433, P=0.001), duration (r=0.305, P=0.018), BDI scores (r=0.312, P=0.012), PDQs (strongly correlated, r=0.555, P<0.001), total mental health score (worse mental health, P=0.004) and its anxiety and depression subscales, pain (P=0.003), and bladder dysfunctions (P=0.012), but not correlated with social support parameters and visual and bowel dysfunctions.
In addition to EDSS score, depression assessed by BDI was strongly correlated with global fatigue (P=0.001) and its subtypes [physical (P=0.015), cognitive (P=0.004), and psychosocial (P=0.037)], more subjective cognitive impairment (P=0.045), more impaired mental health (r=−0.628, P<0.001), and poor global, affective, and positive social support (P=0.001, 0.001, and 0.003) [Table 2].
Besides EDSS and depression, global fatigue was correlated with greater perceived cognitive impairment (r=−0.599, P<0.001), poor mental health (P<0.001), and poor social support (r=0.403, P=0.001). In addition, physical fatigue was correlated with pain (P<0.001) and visual impairment (P=0.041), but not correlated with bowel or bladder control.
In addition to the described high correlation with EDSS, depression, fatigue, and most of the SF-36 scores, subjective cognitive impairment measured by PDQ was correlated with pain (Pain Effects Scale) (high correlation, r=0.452, P<0.001), MHI (r=-0.312, P<0.015), and social support scores (r=−0.305, P=0.018), but not associated with MSQLI symptom scales. Social support was moderately correlated with visual impairment (r=−0.324, P=0.011). Sex, education, and employment were not significantly correlated with depression, fatigue, or different MSQLI parameters.
Thus, most physical subscales of SF-36 were correlated with EDSS and fatigue scores, and mental subscales were correlated with depression and fatigue scores. The PF subscale was negatively correlated with disease duration (r=−0.374, P=0.003).
Sex differences of Multiple Sclerosis Quality of Life Inventory
Comparisons between male and female patients with comparable age, disease duration, and disability revealed a few significant differences. Women showed more anxiety by MHI (P=0.038), and less global, tangible, and emotional social support (P=0.012, 0.003, and 0.015), whereas men showed less sexual satisfaction (P=0.001). No significant sex differences were detected for depression, fatigue, mental status parameters, or perceived cognitive impairment.
| Discussion|| |
A few studies discussed affection of the QoL of MS patients in Arab countries, excluding Egypt, although there were cultural differences . Also, a few studies investigated QoL in ambulatory patients or in patients with no or mild disability ,, and others reported improved or stable QoL with follow-up, although there was increasing disability ,, which could have been due to lower adjustment to disease disability ,. Thus, the current study investigated the correlates of depression, fatigue, and QoL in ambulatory Egyptian patients with MS. All patients were ambulatory and were recruited from the outpatient clinic.
Our study confirmed the compromised QoL domains of Egyptian MS patients compared with that of the healthy population, similar to previous studies ,,. SF (P=0.213) and BP (P=0.033) were the least impaired, when compared with that in controls, in our cohort. Impaired QoL was reported in MS patients with variable disease disability compared with healthy controls in different populations . In a study with closely comparable cohort characteristics to ours, Pugliatti et al.  detected lower SF-36 scores, except for BP, among ambulatory MS patients (91.4% were relapsing remitting) with no or mild disability (EDSS≤3.5), compared with the general population. Likewise, SF and BP were exceptionally comparable to those of controls in prior studies ,. The physical components of the QoL were inversely correlated with disease disability, depression, and fatigue, whereas mental components were correlated with depression and fatigue. This is consistent with the findings of most of the studies that disease disability, depression, and fatigue are the most constant and important predictors of QoL in MS in different countries ,,.
Similar to prior studies, disease disability was associated strongly with the physical components of the QoL (SF-36) rather than with mental items ,. Other studies reported more extended impact of disease disability on physical and mental scores; yet, mental health subscores were of lower correlation ,. This inconsistency could be attributed to variable patent characteristics such as age, duration, disease type, and severity. Nevertheless, our results are in line with studies characterized by lower disability and shorter duration ,.
In contrast, depression was associated with all mental subscales and one physical (RP) subscale, and total fatigue was associated with most of the mental and physical items on the SF-36 because of its physical, psychosocial, and cognitive domains. In agreement with our results, previous studies reported that disability, depression, and fatigue independently affected the physical components, whereas depression and fatigue, rather than disability, affected the mental components of the QoL and suggested favorable impact of treating depression on QoL ,,,,,. Interestingly, depression association was comparable to other studies, despite its higher prevalence in our cohort (81%). Depression effect on the QoL of MS patients is attributed to its impact on patients’ perception, and its association with fatigue and mental and cognitive dysfunctions .
Association of depression and fatigue with perceived cognitive dysfunction, mental health, and insufficient social support was detected as previously reported ,,. Thus, lower disability of the current patients suggests a greater role of other factors, which needs further exploration. Furthermore, this high prevalence of depression could be explained by the use of monthly methylprednisolone in up to 56.7% of patients, which produces adverse psychiatric sequelae and fatigue . The impact of depression and fatigue on sexual dissatisfaction was low, yet similar to that of a previous study . That could be attributed to the smaller number of sexually active patients.
Cognitive impairment was detected in one-fifth of RRMS patients with mild disability . Furthermore, self-perceived cognitive dysfunction was correlated with compromised QoL and depression ,, and PDQ changes over time were correlated with EDSS changes, although there was questionable ability of PDQ to precisely reflect objective cognitive dysfunction ,. Similarly, the current study showed strong association between perceived cognitive impairment and different QoL domains (PF, RP, BP, VT, and MH) and fatigue, and moderate association with depression. In contrast to Robinson et al. , PDQ was strongly correlated with EDSS, but not with patients’ age.
Moreover, the importance of social support and its association with impaired VT and MH domains, depression, fatigue, and impaired cognition and emotional heath were identified in our cohort. Similarly, several studies detected the association of social support with QoL, and other psychosocial factors ,,, and it was identified as an independent predictor of mental, physical, and overall QoL .
In contrast, duration of illness and other psychosocial factors such as sex, age, and educational level were inconsistent and variably reported by different studies . For example, duration of illness was reported as being correlated with QoL in a few studies , but not in others ,,,. Only PF was correlated with disease duration in the present study, consistent with prior studies ,. The role of education level and socioeconomic status could not be assessed properly because of recruitment of patients with average characteristics. Thus, exploration of those factors and other social factors such as residence and religion is warranted.
In the current study, sex had no impact on HRQoL as measured by QoL SF-36 parameters. Several studies have reported no sex-related differences ; however, a few studies detected significant differences ,. Men reported worse sexual satisfaction, similar to prior studies ,, whereas women reported more anxiety and less perceived social support on the MSQLI. This is consistent with a recent large study that reported higher anxiety prevalence among women with RRMS .
Normative values of HRQoL of populations differ between western and eastern countries, rural and urban communities, and with the same community on the basis of economic or social states. These differences are mainly related to changed mental health profiles that are influenced by psychosocial factors such as employment status, lower education level, and economic strain . Consistently, healthy Egyptian controls showed more impaired QoL domains compared with normal populations of other countries, which reflects the impact of cultural psychosocial factors ,. On comparing SF-36 values with those of MS cohorts with mild disability from other countries ,, we found that Egyptian patients had more obvious impairment of GH, VT, and PF, and less impaired BP and SF domains. Moreover, our patients reported lower values of social support, and more impaired cognition and mental health, when compared with data from other countries using similar scales, although the disease severity was lower ,. Accordingly, those factors could explain the greater impairment of QoL in Egyptian MS patients and differences from other countries: notably, the study was conducted during a period of economic strain and political instability.
The current study has some limitations. A larger sample size is needed and results should be restricted to a group of mildly disabled RRMS patients. The cohort of patients was not representative for variable psychosocial factors as patients were all educated, most of them were employed, and were insured, although they had limited resources. Although controls were matched to patients, normative values of SF-36 for all populations are needed.
Despite the limitations, the present study confirmed the considerable impairment of QoL of our patients with early RRMS, and the impact of fatigue, depression, cognitive impairment, and insufficient social support. It discovers the high prevalence of depression among Egyptian patients that imply early detection and management and further research for its correlates. Furthermore, the study highlights the importance of social support especially for women that advocates more supportive care for MS patients to improve QoL, as suggested by prior studies .
The authors thank the patients and controls for their participation in the study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Goretti B, Portaccio E, Zipoli V, Razzolini L, Amato MP. Coping strategies, cognitive impairment, psychological variables and their relationship with quality of life in multiple sclerosis. Neurol Sci 2010; 31(Suppl 2):S227–S230.
Nortvedt MW, Riise T, Myhr KM, Nyland HI. Quality of life as a predictor for change in disability in MS. Neurology 2000; 55:51–54.
Baumstarck K, Pelletier J, Butzkueven H, Fernández O, Flachenecker P, Idiman E et al.
MusiQoL study group. Health-related quality of life as an independent predictor of long-term disability for patients with relapsing-remitting multiple sclerosis. Eur J Neurol 2013; 20:907–914;e78–e79.
Pluta-Fuerst A, Petrovic K, Berger T, Fryze W, Fuchs S, Gold R et al.
Patient-reported quality of life in multiple sclerosis differs between cultures and countries: a cross-sectional Austrian-German-Polish study. Mult Scler 2011; 17:478–486.
Patti F, Amato MP, Trojano M, Bastianello S, Tola MR, Picconi O et al.
Quality of life, depression and fatigue in mildly disabled patients with relapsing-remitting multiple sclerosis receiving subcutaneous interferon beta-1a: 3-year results from the COGIMUS (COGnitive Impairment in MUltiple Sclerosis) study. Mult Scler 2011; 17:991–1001.
Benedict RH, Wahlig E, Bakshi R, Fishman I, Munschauer F, Zivadinov R, Weinstock-Guttman B. Predicting quality of life in multiple sclerosis: accounting for physical disability, fatigue, cognition, mood disorder, personality, and behavior change. J Neurol Sci 2005; 231:29–34.
Janardhan V, Bakshi R. Quality of life in patients with multiple sclerosis: the impact of fatigue and depression. J Neurol Sci 2002; 205:51–58.
D’Alisa S, Miscio G, Baudo S, Simone A, Tesio L, Mauro A. Depression is the main determinant of quality of life in multiple sclerosis: a classification-regression (CART) study. Disabil Rehabil 2006; 28:307–314.
Patti F, Cacopardo M, Palermo F, Ciancio MR, Lopes R, Restivo D, Reggio A. Health-related quality of life and depression in an Italian sample of multiple sclerosis patients. J Neurol Sci 2003; 211:55–62.
Murphy N, Confavreux C, Haas J, König N, Roullet E, Sailer M et al.
Quality of life in multiple sclerosis in France, Germany, and the United Kingdom. Cost of Multiple Sclerosis Study Group. J Neurol Neurosurg Psychiatry 1998; 65:460–466.
Goksel Karatepe A, Kaya T, Gunaydn R, Demirhan A, Ce P, Gedizlioglu M. Quality of life in patients with multiple sclerosis: the impact of depression, fatigue, and disability. Int J Rehabil Res 2011; 34:290–298.
Robinson D Jr, Zhao N, Gathany T, Kim LL, Cella D, Revicki D. Health perceptions and clinical characteristics of relapsing-remitting multiple sclerosis patients: baseline data from an international clinical trial. Curr Med Res Opin 2009; 25:1121–1130.
Yamout B, Issa Z, Herlopian A, El Bejjani M, Khalifa A, Ghadieh AS, Habib RH. Predictors of quality of life among multiple sclerosis patients: a comprehensive analysis. Eur J Neurol 2013; 20:756–764.
Polman CH, Reingold SC, Edan G, Filippi M, Hartung HP, Kappos L et al.
Diagnostic criteria for multiple sclerosis: 2005 revisions to the ‘McDonald Criteria’. Ann Neurol 2005; 58:840–846.
Kurtzke JF. Rating neurologic impairment in multiple sclerosis: an Expanded Disability Status Scale (EDSS). Neurology 1983; 33:1444–1452.
Beck AT, Ward CH, Mendelson M, Mock J, Erbaugh J. An inventory for measuring depression. Arch Gen Psychiatry 1961; 4:561–571.
Ritvo PG, Fischer JS, Miller AD, Andrews H, Paty DW, LaRocca NG. Multiple Sclerosis Quality of Life Inventory: a user’s manual. New York, NY: National Multiple Sclerosis Society; 1997.
Dilorenzo T, Halper J, Picone MA. Reliability and validity of the multiple sclerosis quality of life inventory in older individuals. Disabil Rehabil 2003; 25:891–897.
Coons SJ, Alabdulmohsin SA, Draugalis JR, Hays RD. Reliability of an Arabic version of the RAND-36 Health Survey and its equivalence to the US-English version. Med Care 1998; 36:428–432.
Pugliatti M, Riise T, Nortvedt MW, Carpentras G, Sotgiu MA, Sotgiu S, Rosati G. Self-perceived physical functioning and health status among fully ambulatory multiple sclerosis patients. J Neurol 2008; 255:157–162.
Miller DM, Rudick RA, Baier M, Cutter G, Doughtery DS, Weinstock-Guttman B et al.
Factors that predict health-related quality of life in patients with relapsing-remitting multiple sclerosis. Mult Scler 2003; 9:1–5.
Hopman WM, Coo H, Pavlov A, Day AG, Edgar CM, McBride EV, Brunet DG. Multiple sclerosis: change in health-related quality of life over two years. Can J Neurol Sci 2009; 36:554–561.
Ford HL, Gerry E, Johnson MH, Tennant A. Health status and quality of life of people with multiple sclerosis. Disabil Rehabil 2001; 23:516–521.
McCabe MP, Stokes M, McDonald E. Changes in quality of life and coping among people with multiple sclerosis over a 2 year period. Psychol Health Med 2009; 14:86–96.
Klevan G, Jacobsen CO, Aarseth JH, Myhr KM, Nyland H, Glad S et al.
Health related quality of life in patients recently diagnosed with multiple sclerosis. Acta Neurol Scand 2014; 129:21–26.
Miller A, Dishon S. Health-related quality of life in multiple sclerosis: the impact of disability, gender and employment status. Qual Life Res 2006; 15:259–271.
Hopman WM, Coo H, Edgar CM, McBride EV, Day AG, Brunet DG. Factors associated with health-related quality of life in multiple sclerosis. Can J Neurol Sci 2007; 34:160–166.
Pittion-Vouyovitch S, Debouverie M, Guillemin F, Vandenberghe N, Anxionnat R, Vespignani H. Fatigue in multiple sclerosis is related to disability, depression and quality of life. J Neurol Sci 2006; 243:39–45.
Sorensen PS, Mellgren SI, Svenningsson A, Elovaara I, Frederiksen JL, Beiske AG et al.
NORdic trial of oral Methylprednisolone as add-on therapy to Interferon beta-1a for treatment of relapsing-remitting Multiple Sclerosis (NORMIMS study): a randomised, placebo-controlled trial. Lancet Neurol 2009; 8:519–529.
Patti F, Amato MP, Trojano M, Bastianello S, Tola MR, Goretti B et al.
Cognitive impairment and its relation with disease measures in mildly disabled patients with relapsing-remitting multiple sclerosis: baseline results from the Cognitive Impairment in Multiple Sclerosis (COGIMUS) study. Mult Scler 2009; 15:779–788.
Lovera J, Bagert B, Smoot KH, Wild K, Frank R, Bogardus K et al.
Correlations of Perceived Deficits Questionnaire of Multiple Sclerosis Quality of Life Inventory with Beck Depression Inventory and neuropsychological tests. J Rehabil Res Dev 2006; 43:73–82.
Miller DM, Cohen JA, Kooijmans M, Tsao E, Cutter G, Baier M. Change in clinician-assessed measures of multiple sclerosis and subject-reported quality of life: results from the IMPACT study. Mult Scler 2006; 12:180–186.
Motl RW, McAuley E, Snook EM, Gliottoni RC. Physical activity and quality of life in multiple sclerosis: intermediary roles of disability, fatigue, mood, pain, self-efficacy and social support. Psychol Health Med 2009; 14:111–124.
Pittock SJ, Mayr WT, McClelland RL, Jorgensen NW, Weigand SD, Noseworthy JH, Rodriguez M. Quality of life is favorable for most patients with multiple sclerosis: a population-based cohort study. Arch Neurol 2004; 61:679–686.
Casetta I, Riise T, Wamme Nortvedt M, Economou NT, De Gennaro R, Fazio P et al.
Gender differences in health-related quality of life in multiple sclerosis. Mult Scler 2009; 15:1339–1346.
Jones KH, Ford DV, Jones PA, John A, Middleton RM, Lockhart-Jones H et al.
A large-scale study of anxiety and depression in people with Multiple Sclerosis: a survey via the web portal of the UK MS Register. PLoS One 2012; 7:e41910.
Demiral Y, Ergor G, Unal B, Semin S, Akvardar Y, Kivircik B, Alptekin K. Normative data and discriminative properties of short form 36 (SF-36) in Turkish urban population. BMC Public Health 2006; 6:247.
Pakpour AH, Yekaninejad MS, Mohammadi NK, Molsted S, Zarei F, Patti F, Harrison A. Health-related quality of life in Iranian patients with multiple sclerosis: a cross-cultural study. Neurol Neurochir Pol 2009; 43:517–526.
[Table 1], [Table 2]