Dimensional structure of the SF-36 in neurological patients

Factors Influencing Disabled Stroke Survivors' Quality of Life in Rural China: Based on the Structural Characteristics and Psychometric Properties of the SF-36 Assessment

Many stroke survivors' quality of life is impaired. Few studies of factors influencing their quality of life have been based on the factors tested by the short form 36 instrument. This study did so with 308 physically disabled stroke survivors in rural China. Principal components analysis was applied to refine the dimension structure of the short form 36 assessment, followed by backward multiple linear regression analysis to determine the independent factors influencing quality of life. The structure revealed differed from the generic structure in showing that the mental health and vitality dimensions are not unidimensional. Subjects who reported access to the outdoors as convenient demonstrated better quality of life in all dimensions. Those who exercised regularly achieved better social functioning and negative mental health scores. Other factors influencing a better quality of life in terms of physical functioning were younger age and not being married. Being older and better educated predicted better role-emotion scores. Being female correlated with better social functioning scores, while men scored better on bodily pain. Being less educated predicted higher negative mental health, while being less disabled predicted better physical and social functioning. The results suggest that the SF-36's dimension structure should be re-evaluated before using it to assess stroke survivors.

Measurement Properties of Self-Report Questionnaires for Amyotrophic Lateral Sclerosis: A Systematic Review and Meta-Analysis of Commonly Used Instruments

(1) Background: Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease. There is no evidence on the analysis of the measurement instruments available to assess quality of life in these patients, following the consensus-based standards for the selection of health measurement instruments (COSMIN) checklist; (2) Methods: A systematic review was performed in PubMed, Embase, PEDro, Web of Science and Cochrane. The psychometric properties of the questionnaires were determined by using the COSMIN checklist. Two searches were carried out. This systematic review was registered in PROSPERO (CRD42021249005); (3) Results: There were four published articles that analysed the measurement properties in patients with ALS for the following scales: Amyotrophic Lateral Sclerosis Assessment Questionnaire 40, Amyotrophic Lateral Sclerosis-Specific Quality of Life Questionnaire, Short Form 36 Healthy Survey, Epworth Sleepiness Scale and Sickness Impact Profile. Another five scales also met the inclusion criteria: ALS-Depression-Inventory, State Trait Anxiety-Inventory, World Health Organization Quality of Life, Schedule for the Evaluation of Individual Quality of Life, Amyotrophic Lateral Sclerosis Assessment Questionnaire 5. Most Patient Reported Outcome Measures (PROMs) present a low-quality synthesis of evidence. It was observed an excellent pooled reliability of 0.92 (95% Confidence Interval: 0.83-0.96, I2 = 87.3%) for four dimensions for questionnaires ALSAQ-40. (4) Conclusions: There is little evidence on generic instruments. Future studies are necessary to develop new tools.

High work absence around time of diagnosis of multiple sclerosis is associated with fatigue and relapse rate

BACKGROUND

Multiple sclerosis (MS) is associated with high rates of disability pension and work absence. Little is known about work absence in early MS. The objectives of this study were (1) to assess the prevalence of work absence shortly after MS diagnosis, (2) to explore health-related quality of life (HRQoL) and disease impact in relation to work absence and (3) to investigate demographic and clinical factors that may be associated with high work absence.

METHODS

Patients with relapsing remitting (RRMS) or primary progressive MS (PPMS) were included shortly after MS diagnosis. We collected data on work absence due to MS in the year prior to inclusion, disability (Expanded Disability Status Scale), relapse rate, fatigue (Neurological Fatigue Index), health-related quality of life (HRQoL, 36-Item Short Form Survey) and disease impact (Multiple Sclerosis Impact Scale). For analysis, patients were divided in 2 groups: low work absence (<1 month) and high work absence (≥1 month). Data was analyzed using backward logistic regression techniques.

RESULTS

In total, 90 MS patients participated (80 RRMS, 10 PPMS, mean age = 39.3 years, median disease duration since diagnosis = 0.5 year). Work absence in the year prior to inclusion was reported by 66 patients (73.3%). High work absence of ≥ 1 month was reported by 41 patients (45.6%). Disability, gender, age, disease duration and education did not differ between groups. Patients with high work absence reported a lower HRQoL and higher disease impact compared to patients with low work absence. Backward regression analysis showed that high work absence is associated with being single/not married, fatigue and relapses. The strongest association was found for fatigue (highest fatigue vs. lowest fatigue level: OR total group = 7.8, RRMS = 15.8). In RRMS patients the second-strongest association was relapse rate (≥2 relapses in the past year vs. no relapses: OR 11.1).

CONCLUSION

Prevalence of work absence is high in early MS. Patients with high work absence report a lower HRQoL and a higher disease impact. High work absence is associated with being single/not married, fatigue and relapses. Interventions aimed at fatigue and prevention of relapses may help maintain employment in early MS.

Outcome measurement in neurodegenerative disease: attributes, applications & interpretation

There has been a marked shift from clinically assessed to patient assessed outcomes of treatment in neurodegenerative conditions over recent decades. The use of patient-reported outcome measures (PROMs) provides a method with which researchers and clinicians can gain insightful and meaningful data on health status from the patients' perspective. It is imperative that high-quality PROMs are chosen based upon their measurement properties and their suitability for use in the intended clinical or research context. This review aims to give a brief overview of best practice standards for selecting PROMs, current instruments used in exemplar neurodegenerative conditions and their application in clinical trials and routine measurement.

Mental Health in Multiple Sclerosis Patients without Limitation of Physical Function: The Role of Physical Activity

Multiple sclerosis (MS) patients, in general, show reduced physical function, physical activity, and quality of life. Positive associations between physical activity and quality of life have been reported. In particular, we were interested in the relation between physical activity and mental health in MS patients without limitation of physical function, since limitations of physical function may influence both physical activity and quality of life. Assessment comprised the Baecke questionnaire on physical activity, the Short Form 36 Health Survey (SF-36), and Beck Depression Inventory (BDI). We ranked our sample according to physical activity into four groups and performed an ANOVA to analyze the relationship between levels of physical activity and health-related quality of life (HRQoL). Then we performed a subgroup analysis and included patients with unlimited walking distance and a score of less than 18 in the BDI. Most active vs. inactive patients were compared for the mental subscales of the SF-36 and depression scores. From 632 patients, 265 met inclusion criteria and hence quartiles were filled with 67 patients each. Active and inactive patients did not differ considerably in physical function. In contrast, mental subscales of the SF-36 were higher in active patients. Remarkable and significant differences were found regarding vitality, general health perception, social functioning and mental health, all in favor of physically active patients. Our study showed that higher physical activity is still associated with higher mental health scores even if limitations of physical function are accounted for. Therefore, we believe that physical activity and exercise have considerable health benefits for MS patients.

A review of the measurement properties of the 36-item short-form health survey (SF-36) to determine its suitability for use in an alcohol-dependent population

A psychometric evaluation of the 36-item short-form health survey (SF-36) was undertaken in contemporary studies to assess its suitability for use in an alcohol-dependent population. Three criteria were used to try and determine this: factor analysis, internal consistency reliability and test-retest reliability. Factor analysis revealed that it is mainly consistent with a bidimensional model, internal consistency reliability showed that it consistently provided scores above the recommended threshold and test-retest reliability of the SF-36 highlights that it too provided higher than suggested scores. A conclusion was reached recommending the SF-36 as a reliable screening tool in an alcohol-dependent population, but this is given in caution as no studies were found analysing the instrument in this population.

Construct validity of the SF-12 in three different samples

RATIONALE, AIMS AND OBJECTIVES

Studies have challenged the validity and underlying measurement model of the physical and mental component summary scores of the 36-item Short-Form Health Survey in, for example the elderly and people with neurological disorders. However, it is unclear to what extent these observations translate to physical and mental component summary scores derived from the 12-item short form (SF-12) of the 36-item Short-Form Health Survey. This study evaluated the construct validity of the SF-12 in elderly people and people with Parkinson's disease (PD) and stroke.

METHODS

SF-12 data from a general elderly (aged 75+) population (n = 4278), people with PD (n = 159) and stroke survivors (n = 89) were analysed regarding data quality, reliability (coefficient alpha) and internal construct validity. The latter was assessed through item-total correlations, exploratory and confirmatory factor analyses.

RESULTS

Completeness of data was high (93-98.8%) and reliability was acceptable (0.78-0.85). Item-total correlations argued against the suggested items-to-summary scores structure in all three samples. Exploratory factor analyses failed to support a two-dimensional item structure among elderly and stroke survivors, and cross-loadings of items were seen in all three samples. Confirmatory factor analyses showed lack of fit between empirical data and the proposed items-to-summary measures structure in all samples.

CONCLUSIONS

These observations challenge the validity and interpretability of SF-12 scores among the elderly, people with PD and stroke survivors. The standard orthogonally weighted SF-12 scoring algorithm is cautioned against. Instead, when the assumed two-dimensional structure is supported in the data, oblique scoring algorithms appear preferable. Failure to consider basic scoring assumptions may yield misleading results.

Disease severity affects quality of life of hereditary spastic paraplegia patients

BACKGROUND AND PURPOSE

Hereditary spastic paraplegia (HSP) causes progressive gait disturbance because of degeneration of the corticospinal tract. To assess its impact on Health-Related Quality of Life (HRQoL), we analyzed the correlation of HRQoL with disease severity and clinical symptoms in HSP.

METHODS

HRQoL was assessed by the Short-Form 36 (SF-36) Mental and Physical Component summary scores (MCS and PCS) in 143 German patients with HSP. Disease severity was assessed by the Spastic Paraplegia Rating Scale (SPRS) and landmarks of walking ability. Patients with 'pure' or 'complicated' HSP were compared.

RESULTS

Higher SPRS scores indicating higher disease severity correlated significantly with lower PCS (r = -0.63; P < 0.0005) and MCS (r = -0.38; P < 0.0005) scores. MCS and PCS were reduced in patients with 'complicated' forms compared to 'pure' HSP and with decreasing walking ability.

CONCLUSION

HRQoL is substantially impaired in patients with HSP and decreases with disease severity and the presence of 'complicating' symptoms. Patients are most affected by the physical restraints of their disease, but mental health is impaired as well. HRQoL is a valid parameter in HSP that should be considered in upcoming therapeutical trials.

Dimensionality and summary measures of the SF-36 v1.6: comparison of scale- and item-based approach across ECRHS II adults population

OBJECTIVES

The objective of this study was twofold: 1) to confirm the hypothetical eight scales and two-component summaries of the questionnaire Short Form 36 Health Survey (SF-36), and 2) to evaluate the performance of two alternative measures to the original physical component summary (PCS) and mental component summary (MCS).

METHODS

We performed principal component analysis (PCA) based on 35 items, after optimal scaling via multiple correspondence analysis (MCA), and subsequently on eight scales, after standard summative scoring. Item-based summary measures were planned. Data from the European Community Respiratory Health Survey II follow-up of 8854 subjects from 25 centers were analyzed to cross-validate the original and the novel PCS and MCS.

RESULTS

Overall, the scale- and item-based comparison indicated that the SF-36 scales and summaries meet the supposed dimensionality. However, vitality, social functioning, and general health items did not fit data optimally. The novel measures, derived a posteriori by unit-rule from an oblique (correlated) MCA/PCA solution, are simple item sums or weighted scale sums where the weights are the raw scale ranges. These item-based scores yielded consistent scale-summary results for outliers profiles, with an expected known-group differences validity.

CONCLUSIONS

We were able to confirm the hypothesized dimensionality of eight scales and two summaries of the SF-36. The alternative scoring reaches at least the same required standards of the original scoring. In addition, it can reduce the item-scale inconsistencies without loss of predictive validity.

The development of patient-reported outcome indices for multiple sclerosis (PRIMUS)

BACKGROUND

Complex diseases such as multiple sclerosis (MS) present dilemmas over the choice of patient-reported outcome measures as no single scale can inform on all types of MS impact from the patient's perspective.

OBJECTIVE

To develop an outcome tool, the Patient-Reported Indices for Multiple Sclerosis (PRIMUS), to assess MS symptoms, activities, and quality of life.

METHODS

PRIMUS content was derived from qualitative interviews with UK MS patients and checked by clinical experts. Semi-structured cognitive debriefing interviews assessed scale face and content validity. PRIMUS scaling properties, reliability, and construct validity were assessed by a test-retest postal survey.

RESULTS

Cognitive debriefing interviews (n = 15) demonstrated scale clarity, relevance, and comprehensiveness. The postal survey was completed by 135 patients with MS. After removal of misfitting items and those exhibiting differential item functioning, all scales fitted the Rasch model, confirming unidimensionality. For all scales, test-retest reliability exceeded 0.80. Scale scores were related to perceived MS severity, general health, and symptoms of depression. Moderate correlations were observed between PRIMUS and Nottingham Health Profile scores.

CONCLUSIONS

Clinicians and researchers can have confidence in scores obtained by respondents on the PRIMUS. The PRIMUS will aid the assessment of the impact of MS from the patient's perspective.

Whose quality of life? Ethical implications in patient-reported health outcome measurement

OBJECTIVES

Patient-reported health status questionnaires intend to assess illness and therapy from the patients' perspective. To provide fair and valid assessments, they should be equally relevant to major subsets of respondents. Furthermore, disease-specific measures are assumed to be perceived as more relevant than generic ones. This study assessed these assumptions among people with Parkinson's disease.

METHODS

Cross-sectional data from 202 people with Parkinson's disease (54% men; mean age, 70) were analyzed regarding patient-rated relevance and predictors of patient-rated poor relevance of two generic [the 36-item Short Form Health Survey (SF-36) and Nottingham Health Profile (NHP)] and one disease-specific [Parkinson's Disease Questionnaire (PDQ-39)] health status questionnaire.

RESULTS

There were no differences in relevance ratings across the questionnaires. Poorer overall quality of life [odds ratio (OR), 2.459] and mental health (OR, 1.023) were associated with poorer patient-rated relevance of the SF-36, and higher age was associated with poorer patient-rated relevance of the PDQ-39 (OR, 1.040). No significant predictors were found for the NHP.

CONCLUSIONS

The PDQ-39 failed to meet the assumption that disease-specific scales are more relevant than generic ones. Nevertheless, the most important implication of this study is an ethical one. Because the relevance of the SF-36 and PDQ-39 is perceived as poorer by those who fare least well and by older people, these scales may not reflect the perspectives of these groups. This challenges bioethical principles and threatens scientific validity. Perceived relevance of patient-centered outcomes needs to be considered, or the voice of vulnerable groups may be silenced, fair inferences prohibited, and opportunities for improved care lost.

Utilization of health care by patients with multiple sclerosis is based on professional and patient-defined health needs

OBJECTIVE

This cross-sectional study investigates healthcare utilization, and determines which predisposing, enabling, and health factors are associated with healthcare utilization among 121 patients with multiple sclerosis (MS).

METHODS

Data on patient-related predisposing, enabling, and health factors were collected by means of written questionnaires and a home visit from a well-trained physiotherapist.

RESULTS

Of the 121 patients with MS (mean age 43 years, mean score on the Expanded Disability Status Scale 3.5, disease duration 6 years), 16% were hospitalized in the previous year; 62% consulted their general practitioner, and 69% consulted their neurologist in the previous 6 months. Other medical specialists were consulted in the 6-month period by 50% of the study population. In a 4-week period preceding the home visit, 41% of the patients were treated by an allied healthcare professional. Multivariate logistic regression analyses showed that consulting the general practitioner, the neurologist, other medical specialists, and allied healthcare professionals, and the use of equipment/aids by MS patients is primarily related to their health, either as perceived by the patients themselves or defined by the professional.

CONCLUSIONS

MS patients in the Netherlands make appropriate use of healthcare facilities, because their utilization can predominantly be explained by health-related factors, and not by predisposing or enabling factors.