Validation of a Dutch version of the Neurological Fatigue Index (NFI-MS) for patients with multiple sclerosis in the Netherlands

Purpose

Fatigue is a complex, multidimensional construct. Most questionnaires measuring fatigue do not meet the standards for good measurement properties. Therefore, the Neurological Fatigue Index for multiple sclerosis (NFI-MS) is recently developed using thorough methods. The aim of this study was to develop and validate the Dutch version of the NFI-MS.

Methods

The original English version of the NFI-MS was translated into Dutch using a forward–backward procedure. Reliability (intraclass correlation coefficient (ICC) and standard error of measurement (SEM)) were assessed for the summary score and the four subscale scores separately. Construct validity was assessed by testing hypotheses about expected correlations between the NFI-MS and other constructs (e.g. impact on functioning and depression) and expected differences on NFI scores between groups defined on the basis of disease type and work status.

Results

The reliability analyses (n = 118) showed that the ICC was 0.78 (NFI-MS summary) and ranged from 0.75 to 0.83 for the four subscales and the SEM was 2.5 (NFI-MS summary) and ranged from 1.1 to 2.2 for the four subscales. For construct validity (n = 136), 50 out of the 57 expected hypotheses were confirmed (88 %).

Conclusion

The present study shows that the Dutch version of the NFI-MS is a reliable and valid self-report questionnaire for measuring fatigue in Dutch patients with MS.     

Validation of the Neurological Fatigue Index for Stroke (NFI-Stroke)

ABSTRACT: Background Fatigue is a common symptom in Stroke. Several self-report scales are available to measure this debilitating symptom but concern has been expressed about their construct validity. Objective To examine the reliability and validity of a recently developed scale for multiple sclerosis (MS) fatigue, the Neurological Fatigue Index (NFI-MS), in a sample of stroke patients. Method Six patients with stroke participated in qualitative interviews which were analysed and the themes compared for equivalence to those derived from existing data on MS fatigue. 999 questionnaire packs were sent to those with a stroke within the past four years. Data from the four subscales, and the Summary scale of the NFI-MS were fitted to the Rasch measurement model. Results Themes identified by stroke patients were consistent with those identified by those with MS. 282 questionnaires were returned and respondents had a mean age of 67.3 years; 62% were male, and were on average 17.2 (SD 11.4, range 2-50) months post stroke. The Physical, Cognitive and Summary scales all showed good fit to the model, were unidimensional, and free of differential item functioning by age, sex and time. The sleep scales failed to show adequate fit in their current format. Conclusion Post stroke fatigue appears to be represented by a combination of physical and cognitive components, confirmed by both qualitative and quantitative processes. The NFI-Stroke, comprising a Physical and Cognitive subscale, and a 10-item Summary scale, meets the strictest measurement requirements. Fit to the Rasch model allows conversion of ordinal raw scores to a linear metric.     

Interpreting scores on multiple sclerosis-specific patient reported outcome measures (the PRIMUS and U-FIS)

Background  

The PRIMUS is a Multiple Sclerosis (MS)-specific suite of outcome measures including assessments of QoL (PRIMUS QoL, scored 0-22) and activity limitations (PRIMUS Activities, scored 0-30). The U-FIS is a measure of fatigue impact (scored 0-66). These measures have been fully validated previously using an MS sample with mixed diagnoses. The aim of the present study was to validate the measures further in a specifically Relapse Remitting MS (RRMS) sample and to provide preliminary evidence of the responder definitions (RD; also known as minimal important difference) for these instruments.     

Gastroparesis Cardinal Symptom Index (GCSI): Development and validation of a patient reported assessment of severity of gastroparesis symptoms

BACKGROUND: Patient-rated symptom assessments are needed for evaluating the effectiveness of medical treatments and for monitoring outcomes in gastroparesis. OBJECTIVE: This paper summarizes the development and psychometric evaluation of a new instrument, the Gastroparesis Cardinal Symptom Index (GCSI), for assessing severity of symptoms associated with gastroparesis. METHODS: The GCSI was based on reviews of the medical literature, patient focus groups, and interviews with clinicians. A sample of 169 patients with a documented diagnosis of gastroparesis participated in the psychometric evaluation study. Patients completed the GCSI, the SF-36 Health Survey, and disability days questions at baseline and after 8 weeks. A randomly selected sub-sample of 30 subjects returned at 2 weeks to assess test retest reliability. Clinicians rated severity of symptoms, and both clinicians and patients rated change in gastroparesis-related symptoms over the 8 week study. RESULTS: The GCSI is based on three subscales: post-prandial fullness/early satiety (4 items); nausea/vomiting (3 items), and bloating (2 items). Internal consistency reliability was 0.84 for the GCSI total score and ranged from 0.83 to 0.85 for the subscale scores. Two week test retest reliability was 0.76 for the total score and ranged from 0.68 to 0.81 for subscale scores. Construct validity was supported, given that we observed significant relationships between clinician assessed symptom severity and GCSI total score, significant differences between gastroparesis and dyspepsia patients (n = 760) on GCSI total (p < 0.0001) and subscale scores (p < 0.03 to p < 0.0001), moderate and significant relationships between GCSI total and SF-36 scores, and significant associations between GCSI total score and reports of restricted activity and bed disability days. Patients with greater symptom severity, as rated by clinicians, reported more symptom severity on GCSI total score. GSCI total scores were responsive to changes in overall gastroparesis symptoms as assessed by clinicians (p < 0.0001) and patients (p = 0.0004). CONCLUSION: The findings of this study indicate that the GCSI is a reliable and valid instrument for measuring symptom severity in patients with gastroparesis.     

Measuring fatigue in persons with multiple sclerosis: creating a crosswalk between the Modified Fatigue Impact Scale and the PROMIS Fatigue Short Form

Purpose

To create cross-walk tables to associate scores for the Modified Fatigue Impact Scale (MFIS) with scores for the Patient Reported Outcome Measurement Information System (PROMIS) Fatigue Short Form (SF) in persons with Multiple Sclerosis (MS).

Methods

Cross-walk tables were created using equipercentile linking and based on data collected at one time point in a longitudinal study of persons with MS (N?=?458). Validation of the tables was conducted using data collected at a subsequent time point (N?=?444). Deviations between estimates and actual scores were compared across levels of fatigue. The impact of sample size on the precision of sample mean estimates was evaluated using bootstrapping.

Results

Correlations between deviations and fatigue level for the PROMIS Fatigue SF and MFIS were (?0.31) and (?0.30), respectively, indicating moderately greater deviations with lower fatigue scores. Estimated sample means were impacted by sample size.

Conclusions

Cross-walk tables allow data from studies using different measures of fatigue to be combined to achieve larger sample sizes and to compare results. These tables are valid for group-level analyses with sample sizes of 150 or greater.     

Development and validation of a scale to measure work-related fatigue and recovery: the Occupational Fatigue Exhaustion/Recovery Scale (OFER)

OBJECTIVE: Various empirical studies link persistent failure to recover from acute fatigue to the evolution of chronic fatigue. However, existing fatigue measurement scales do not tend to distinguish between acute and chronic fatigue elements well, and none include a measure of effective recovery from fatigue. METHODS: The 15 item Occupational Fatigue Exhaustion Recovery (OFER) scale has been developed and validated in three study populations specifically to measure work-related fatigue. RESULTS: The OFER scale possesses robust, gender-bias free psychometric characteristics. Its three subscales identify and distinguish between chronic work-related fatigue traits, acute end-of-shift states and effective fatigue recovery between shifts. CONCLUSION: These studies confirm the mediating role of intershift-shift recovery in the evolution of adaptive end-of-shift fatigue states to maladaptive persistent fatigue traits. The OFER scale is suggested as a potentially valuable new tool for use in work-related fatigue research.     

Establishing construct validity for the thyroid-specific patient reported outcome measure (ThyPRO): an initial examination

Objective  To establish a reliable and valid scale structure of a patient-reported outcome measuring thyroid-specific quality of life. Methods  The 98-item ThyPRO questionnaire was administered to patients with benign thyroid diseases at two university hospitals. Multi-trait scaling was performed, evaluating lack of convergent validity (item-own scale polyserial correlation <0.40) or lack of discriminant validity (item-other scale correlation higher than item-own scale correlation) of the hypothesized scale structure. Analyses were repeated in clinical and sociodemographic subgroups and with Pearson correlations. Reliability was estimated by Cronbach’s α, both conventionally and with polychoric correlations. Results  In total, 904 patients (69%) responded. Initial multitrait scaling analysis identified 25 scaling errors. Twelve items were omitted from the scale structure, and a re-analysis showed complete convergent validity and only two instances of lack of discriminant validity. Pearson correlations yielded similar results. Across all subgroups, convergent validity was complete, and discriminant validity was found in 99.2% of tests. Lack of discriminant validity was mainly between physical symptoms and psychological and disease-impact scales. Cronbach’s α was acceptable (>0.70, >0.80 with polychoric correlations) for all 13 scales. Conclusion  A reliable scale structure displaying complete convergent and almost complete discriminant validity was established in general analyses and in distinct clinical subgroups of patients with benign thyroid diseases. Researchers who want to use the ThyPRO may contact the first author (T.Watt@rh.dk).     

The multiple sclerosis rating scale, revised (MSRS-R): Development, refinement, and psychometric validation using an online community

ABSTRACT: BACKGROUND: In developing the PatientsLikeMe online platform for patients with Multiple Sclerosis (MS), we required a patient-reported assessment of functional status that was easy to complete and identified disability in domains other than walking. Existing measures of functional status were inadequate, clinician-reported, focused on walking, and burdensome to complete. In response, we developed the Multiple Sclerosis Rating Scale (MSRS). METHODS: We adapted a clinician-rated measure, the Guy's Neurological Disability Scale, to a self-report scale and deployed it to an online community. As part of our validation process we reviewed discussions between patients, conducted patient cognitive debriefing, and made minor improvements to form a revised scale (MSRS-R) before deploying a cross-sectional survey to patients with relapsing-remitting MS (RRMS) on the PatientsLikeMe platform. The survey included MSRS-R and comparator measures: MSIS-29, PDDS, NARCOMS Performance Scales, PRIMUS, and MSWS-12. RESULTS: In total, 816 RRMS patients responded (19% response rate). The MSRS-R exhibited high internal consistency (Cronbach's alpha = .86). The MSRS-R walking item was highly correlated with alternative walking measures (PDDS, ? = .84; MSWS-12, r= .83; NARCOMS mobility question, ? = .86). MSRS-R correlated well with comparison instruments and differentiated between known groups by PDDS disease stage and relapse burden in the past two years. Factor analysis suggested a single factor accounting for 51.5% of variance.& CONCLUSIONS: The MSRS-R is a concise measure of MS-related functional disability, and may have advantages for disease measurement over longer and more burdensome instruments that are restricted to a smaller number of domains or measure quality of life. Studies are underway describing the use of the instrument in contexts outside our online platform such as clinical practice or trials. The MSRS-R is released for use under creative commons license.     

Development and validation of a patient‐reported outcome measure for patients with chronic respiratory failure: The CRF‐PROM scale

BackgroundVarious health‐related quality‐of‐life (HRQOL) tools are used to evaluate patients with chronic respiratory failure (CRF), but there is a relative lack of tools available for the evaluation of social support and treatment in these patients. The present study focused on the development of a systematic patient‐reported outcome measure (PROM) tool for use in patients with CRF.MethodsThe CRF‐PROM scale conceptual framework and item bank were generated after reviewing the corresponding literature and HRQOL scales, interviewing CRF patients and focus groups. After creation of the initial scale, the items in the scale were selected through two item selection theories, and the final scale was created. The reliability, validity and feasibility of the final scale were assessed.ResultsThe CRF‐PROM scale includes four domains (i.e., physiological domain, psychological domain, social domain and therapeutic domain) and 10 dimensions. After the item selection process, the final scale included 50 items. Cronbach''s α coefficients, which were all above 0.7, indicated the reliability of the scale. The results of structural validity met the relevant standards of confirmatory factor analysis. The response rates of the preinvestigation and the formal investigation were 93.3% and 97.6%, respectively.ConclusionsThe CRF‐PROM scale developed in the present study is effective and reliable. It could be used widely in the posthospital management of patients, in CRF studies and in clinical trials of new medical products and interventions.Patient or Public ContributionParticipants from eight different hospitals and communities participated in the development or validation phase of the CRF‐PROM scale.     

A novel approach to estimate the minimally important difference for the fatigue impact scale in multiple sclerosis patients

Purpose  

The Fatigue Impact Scale (FIS) has been used extensively to assess the impact of fatigue on health-related quality of life (HRQOL) in multiple sclerosis (MS). The objective of this study was to estimate the minimally important difference (MID) of the FIS to facilitate the interpretation of the scale in patients with MS.     

Natalizumab in multiple sclerosis: unclear patient benefits

Two large randomised clinical trials were published in March 2006 that evaluated the effect of natalizumab on the incidence of disease exacerbation in patients with multiple sclerosis (MS). Both trials showed that natalizumab reduces the incidence of MS exacerbations, but it is unclear whether patients ultimately benefited from treatment. It is clear that natalizumab is associated with serious adverse events, such as progressive multifocal leukoencephalopathy. Therefore, the use of natalizumab in patients with MS cannot be considered advisable at this time.     

Fatigue characteristics in multiple sclerosis: the North American Research Committee on Multiple Sclerosis (NARCOMS) survey

Background  

Fatigue is a common disabling symptom of multiple sclerosis (MS) and has a significantly negative impact on quality of life. Persons with MS enrolled in the North American Research Committee on Multiple Sclerosis (NARCOMS) Patient Registry are invited to complete follow-up surveys every six months to update their original registration information. One of these surveys was designed to focus on the severity and impact of fatigue, and its association with other clinical parameters of MS such as physical disability.     

Symptom clusters for revising scale membership in the analysis of prostate cancer patient reported outcome measures: a secondary data analysis of the Medical Research Council RT01 trial (ISCRTN47772397)

Purpose

To investigate the role of symptom clusters in the analysis and utilisation of patient reported outcome measures (PROMs) for data modelling and clinical practice. To compare symptom clusters with scales, and to explore their value in PROMs interpretation and symptom management.

Methods

A dataset called RT01 (ISCRTN47772397) of 843 prostate cancer patients was used. PROMs were reported with the University of California, Los Angeles Prostate Cancer Index (UCLA-PCI). Symptom clusters were explored with hierarchical cluster analysis (HCA) and average linkage method (correlation?>?0.6). The reliability of the Urinary Function Scale was evaluated with Cronbach’s Alpha. The strength of the relationship between the items was investigated with Spearman’s correlation. Predictive accuracy of the clusters was compared to the scales by receiver operating characteristic (ROC) analysis. Presence of urinary symptoms at 3 years measured with the late effects on normal tissue: subjective, objective, management tool (LENT/SOM) was an endpoint.

Results

Two symptom clusters were identified (urinary cluster and sexual cluster). The grouping of symptom clusters was different than UCLA-PCI Scales. Two items of the urinary function scales (“number of pads” and “urinary leak interfering with sex”) were excluded from the urinary cluster. The correlation with the other items in the scale ranged from 0.20 to 0.21 and 0.31 to 0.39, respectively. Cronbach’s Alpha showed low correlation of those items with the Urinary Function Scale (0.14–0.36 and 0.33–0.44, respectively). All urinary function scale items were subject to a ceiling effect. Clusters had better predictive accuracy, AUC?=?0.70?–0.65, while scales AUC?=?0.67–0.61.

Conclusion

This study adds to the knowledge on how cluster analysis can be applied for the interpretation and utilisation of PROMs. We conclude that multiple-item scales should be evaluated and that symptom clusters provide a study-specific approach for modelling and interpretation of PROMs.

     

The Cervical Dystonia Impact Profile (CDIP-58): Can a Rasch developed patient reported outcome measure satisfy traditional psychometric criteria?

Background  

The United States Food and Drug Administration (FDA) are currently producing guidelines for the scientific adequacy of patient reported outcome measures (PROMs) in clinical trials, which will have implications for the selection of scales used in future clinical trials. In this study, we examine how the Cervical Dystonia Impact Profile (CDIP-58), a rigorous Rasch measurement developed neurologic PROM, stands up to traditional psychometric criteria for three reasons: 1) provide traditional psychometric evidence for the CDIP-58 in line with proposed FDA guidelines; 2) enable researchers and clinicians to compare it with existing dystonia PROMs; and 3) help researchers and clinicians bridge the knowledge gap between old and new methods of reliability and validity testing.     

Anorexia nervosa in a patient with multiple sclerosis: A case report

A case is presented in which a 29-year-old married woman developed anorexia nervosa following an 8-year history of multiple sclerosis. She was admitted to a specialized eating disorders unit for refeeding following a dramatic reduction in her body weight.     

Experience of services as a key outcome in amyotrophic lateral sclerosis (ALS) care: the case for a better understanding of patient experiences

People with amyotrophic lateral sclerosis (ALS) frequently express dissatisfaction with services. Patient satisfaction with services in ALS care is not always measured and service user perspectives are not usually included when evaluating the outcomes of care. There is a lack of consensus on what constitutes satisfaction for patients in ALS care. To date, health care professionals' conceptualization of outcomes in ALS care has excluded measures of patient satisfaction with services. Exploring the context of the ALS service user experience of care will identify a conceptual framework that will include the domains of satisfaction with care for patients with ALS. An instrument that draws on the ALS patient perspective of services, developed on the basis of qualitative investigation, should be used to measure satisfaction with services.     

Construction and validation of a fatigue impact scale for daily administration (D-FIS)

The fatigue impact scale (FIS) was developed previously as a symptom-specific profile measure of health-related quality of the (HRQoL) for use in medical conditions in which fatigue is a prominent chronic symptom. Thus, it was not developed to be a responsive measure of daily changes in fatigue. This study describes the development and initial validation of an adaptation of the FIS for daily use. Items for the daily fatigue impact scale (D-FIS) were selected from the pool of original FIS items through Rasch analyses of existing data. The reduced-item FIS was administered to a sample of 93 subjects with flu-like illness, 25 of whom were followed for a 21-day period. Rasch analyses were used to further reduce the scale to a minimum number of items that represented a unidimensional measure of self-reported fatigue impact. This 8-item D-FIS demonstrated good relations to flu symptom ratings and to other general health ratings. It also proved to be a responsive measure of change in reported fatigue impact for subjects who were followed longitudinally. This initial validation study indicates that the D-FIS has considerable promise as a valid measure of the subjective daily experience of fatigue.