Cross-diagnostic validity of the Nottingham Health Profile Index of Distress (NHPD)

Measurement properties of the minimal insomnia symptom scale (MISS) in adolescents

Background

The Minimal Insomnia Symptom Scale (MISS) is a three-item screening instrument that has been found to be psychometrically sound and capable of screening for insomnia among adults and older people. This study aimed to test the measurement properties of the MISS together with an additional item focusing on daytime functioning among adolescents using the Rasch measurement model.

Methods

A cross-sectional design was used, and data from adolescents (age 13–17 years, n = 3022) were analyzed using the Rasch measurement model.

Results

The MISS had good measurement properties. When adding the item “daytime disturbance”, the measurement properties deteriorated. When replacing the original MISS item “not rested by sleep” with the item “daytime disturbance”, the measurement properties slightly improved. We label this new scale the MISS-Revised (MISS-R). The reliability was better for the MISS-R (0.55) compared to the MISS (0.50). The optimal cut-off was found to be > 6 points, both for the MISS and the MISS-R.

Conclusions

This study provides general support that both the MISS as well as the MISS-R have good fit to the Rasch model. At this stage, neither the MISS nor the MISS-R can be advocated over the other for use among adolescents, although the MISS-R had slightly better reliability than the MISS. Additional studies are needed to determine the clinically optimal cut-score for identification of insomnia.

Co-calibrating quality-of-life scores from three pulmonary disorders: implications for comparative-effectiveness research

Background Efficient use of health resources requires accurate outcome assessment. Disease-specific patient-reported outcome (PRO) measures are designed to be highly relevant to patients with a specific disease. They have advantages over generic PROs that lack relevance to patient groups and miss crucial impacts of illness. It is thought that disease-specific measurement cannot be used in comparative effectiveness research (CER). The present study provides further evidence of the value of disease-specific measures in making valid comparisons across diseases. Methods The Asthma Life Impact Scale (ALIS, 22 items), Living with Chronic Obstructive Pulmonary Disease (LCOPD, 22 items) scale, and Cambridge Pulmonary Hypertension Outcome Review (CAMPHOR, 25 items) were completed by 140, 162, and 91 patients, respectively. The three samples were analyzed for fit to the Rasch model, then combined into a scale consisting of 58 unique items and re-analyzed. Raw scores on the three measures were co-calibrated and a transformation table produced. Results The scales fit the Rasch model individually (ALIS Chi(2) probability value (p-Chi(2)) = 0.05; LCOPD p-Chi(2 )=( )0.38; CAMPHOR p-Chi(2 )=( )0.92). The combined data also fit the Rasch model (p-Chi(2 )=( )0.22). There was no differential item functioning related to age, gender, or disease. The co-calibrated scales successfully distinguished between perceived severity groups (p < 0.001). Limitations The samples were drawn from different sources. For scales to be co-calibrated using a common item design, they must be based on the same theoretical construct, be unidimensional, and have overlapping items. Conclusions The results showed that it is possible to co-calibrate scores from disease-specific PRO measures. This will permit more accurate and sensitive outcome measurement to be incorporated into CER. The co-calibration of needs-based disease-specific measures allows the calculation of γ scores that can be used to compare directly the impact of any type of interventions on any diseases included in the co-calibration.

Measurement properties of the minimal insomnia symptom scale as an insomnia screening tool for adults and the elderly

BACKGROUND

The psychometric properties of the three-item Minimal Insomnia Symptom Scale (MISS) were evaluated using the classical test theory. Different cut-offs for identifying insomnia were suggested in two age groups (≥6 and ≥7 among adult and elderly people, respectively). The aim of the present study was to test the measurement properties of the MISS using the Rasch measurement model, with special emphasis on differential item functioning by gender and age.

METHODS

Cross-sectional MISS data from adult (age 20-64 years, n = 1075) and elderly (age 65+, n = 548) populations were analysed using the Rasch measurement model.

RESULTS

Data generally met Rasch model requirements and the scale could separate between two distinct groups of people. Differential item functioning was found by age but not gender. The difference between the adult and elderly samples was lower for the originally recommended ≥6 points cut-off (0.09 logits) than for the ≥7 points cut-off (0.23 logits), but greater at the lower and higher ends of the scale.

CONCLUSIONS

This study provides general support for the measurement properties of the MISS. Caution should be exercised in comparing raw MISS scores between age groups, but applying a ≥6 cut-off appears to allow for valid comparisons between adults and the elderly regarding the presence of insomnia. Nevertheless, additional studies are needed to determine the clinically optimal cut-score for identification of insomnia.

Measurement invariance across chronic conditions: a systematic review and an empirical investigation of the Health Education Impact Questionnaire (heiQ™)

BACKGROUND

To examine whether lack of measurement invariance (MI) influences mean comparisons among different disease groups, this paper provides (1) a systematic review of MI in generic constructs across chronic conditions and (2) an empirical analysis of MI in the Health Education Impact Questionnaire (heiQ™).

METHODS

(1) We searched for studies of MI among different chronic conditions in online databases. (2) Multigroup confirmatory factor analyses were used to study MI among five chronic conditions (orthopedic condition, rheumatism, asthma, COPD, cancer) in the heiQ™ with N = 1404 rehabilitation inpatients. Impact on latent and composite mean differences was examined.

RESULTS

(1) A total of 30 relevant studies suggested that about one in three items lacked MI. However, only four studies examined impact on latent mean differences. Scale means were only affected in one of these three studies. (2) Across the eight heiQ™ scales, seven scales had items with lack of MI in at least one disease group. However, in only two heiQ™ scales were some latent or composite mean differences affected.

CONCLUSIONS

Lack of MI among disease groups is common and may have a relevant influence on mean comparisons when using generic instruments. Therefore, when comparing disease groups, tests of MI should be implemented. More studies of MI and according impact on mean differences in generic questionnaires are needed.

Measurement invariance across chronic conditions: a systematic review and an empirical investigation of the Health Education Impact Questionnaire (heiQ™)

BACKGROUND

To examine whether lack of measurement invariance (MI) influences mean comparisons among different disease groups, this paper provides (1) a systematic review of MI in generic constructs across chronic conditions and (2) an empirical analysis of MI in the Health Education Impact Questionnaire (heiQ™).

METHODS

(1) We searched for studies of MI among different chronic conditions in online databases. (2) Multigroup confirmatory factor analyses were used to study MI among five chronic conditions (orthopedic condition, rheumatism, asthma, COPD, cancer) in the heiQ™ with N = 1404 rehabilitation inpatients. Impact on latent and composite mean differences was examined.

RESULTS

(1) A total of 30 relevant studies suggested that about one in three items lacked MI. However, only four studies examined impact on latent mean differences. Scale means were only affected in one of these three studies. (2) Across the eight heiQ™ scales, seven scales had items with lack of MI in at least one disease group. However, in only two heiQ™ scales were some latent or composite mean differences affected.

CONCLUSIONS

Lack of MI among disease groups is common and may have a relevant influence on mean comparisons when using generic instruments. Therefore, when comparing disease groups, tests of MI should be implemented. More studies of MI and according impact on mean differences in generic questionnaires are needed.

Fatigue in Parkinson's disease: measurement properties of a generic and a condition-specific rating scale

CONTEXT

High-quality fatigue rating scales are needed to advance the understanding of fatigue and determine the efficacy of interventions. Several fatigue scales are used in Parkinson's disease, but few have been tested using modern psychometric methodology (Rasch analysis).

OBJECTIVES

To examine the measurement properties of the generic Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) scale and the condition-specific 16-item Parkinson Fatigue Scale (PFS-16) using Rasch analysis.

METHODS

Postal survey data (n=150; 47% women; mean age 70 years) were Rasch analyzed. The PFS-16 scores were tested according to both the original polytomous and the suggested alternative dichotomized scoring methods.

RESULTS

The PFS-16 showed overall Rasch model fit, whereas the FACIT-F showed signs of misfit, which probably was the result of a sleepiness-related item and mixing of positively/negatively worded items. There was no differential item functioning by disease duration but by fatigue status (greater likelihood of needing to sleep or rest during the day among people classified as nonfatigued) in the PFS-16 and FACIT-F. However, this did not impact total score-based estimated person measures. Targeting and reliability (≥0.86) were good, but the dichotomized PFS-16 showed compromised measurement precision. Polytomous and dichotomized PFS-16 and FACIT-F scores identified six, three, and four statistically distinct sample strata, respectively.

CONCLUSION

We found general support for the measurement properties of both scales. However, polytomous PFS-16 scores exhibited advantages compared with dichotomous PFS-16 and FACIT-F scores. Dichotomization of item responses compromises measurement precision and the ability to separate people, and should be avoided.

The Nottingham Health Profile: a feasible questionnaire for nursing home residents?

BACKGROUND

The Nottingham Health Profile (NHP) assesses perceived emotional, social, and physical health problems and the extent to which such problems affect daily activities. The objective of our study was to determine the feasibility of the NHP for nursing home residents.

METHODS

A prospective multicenter observational study was conducted in 11 nursing homes from April 2008 to December 2009 in which 286 newly admitted residents were included. Cognitive status was evaluated using the Mini-Mental State Examination (MMSE). The feasibility of the NHP was determined by administration rate, time and type of administration, and missing items. A cut-off point stating the MMSE score up to which the NHP can be applied was determined with receiver operating characteristics curves (ROC). Internal consistency (Cronbach's α) and test-retest reliability (intraclass correlation; ICC) were evaluated.

RESULTS

Administration rate was 44.4% (n = 127) ranging from 76.1% for normal residents to 5.9% for residents with a severe cognitive impairment. An average of 12.6 (SD + 6.0) minutes was required for data collection and 92.1% (n = 117) of the questionnaires were completed during an interview. Frequently missing items were in the domain "Pain" (47.2). MMSE scores were significantly higher in the group with a completed NHP (P < 0.001) and analyses of ROC curves indicated a cut-off point of >16 on the MMSE score. Cronbach's α was >0.7 in four domains and >0.6 in two domains, while the ICC in all domains was >0.7.

CONCLUSION

The NHP is a feasible questionnaire for residents with normal cognitive function and moderate cognitive impairment, and can be administered in nursing homes.

Can manual ability be measured with a generic ABILHAND scale? A cross-sectional study conducted on six diagnostic groups

OBJECTIVES

Several ABILHAND Rasch-built manual ability scales were previously developed for chronic stroke (CS), cerebral palsy (CP), rheumatoid arthritis (RA), systemic sclerosis (SSc) and neuromuscular disorders (NMD). The present study aimed to explore the applicability of a generic manual ability scale unbiased by diagnosis and to study the nature of manual ability across diagnoses.

DESIGN

Cross-sectional study.

SETTING

Outpatient clinic homes (CS, CP, RA), specialised centres (CP), reference centres (CP, NMD) and university hospitals (SSc).

PARTICIPANTS

762 patients from six diagnostic groups: 103 CS adults, 113 CP children, 112 RA adults, 156 SSc adults, 124 NMD children and 124 NMD adults.

PRIMARY AND SECONDARY OUTCOME MEASURES

Manual ability as measured by the ABILHAND disease-specific questionnaires, diagnosis and nature (ie, uni-manual or bi-manual involvement and proximal or distal joints involvement) of the ABILHAND manual activities.

RESULTS

The difficulties of most manual activities were diagnosis dependent. A principal component analysis highlighted that 57% of the variance in the item difficulty between diagnoses was explained by the symmetric or asymmetric nature of the disorders. A generic scale was constructed, from a metric point of view, with 11 items sharing a common difficulty among diagnoses and 41 items displaying a category-specific location (asymmetric: CS, CP; and symmetric: RA, SSc, NMD). This generic scale showed that CP and NMD children had significantly less manual ability than RA patients, who had significantly less manual ability than CS, SSc and NMD adults. However, the generic scale was less discriminative and responsive to small deficits than disease-specific instruments.

CONCLUSIONS

Our finding that most of the manual item difficulties were disease-dependent emphasises the danger of using generic scales without prior investigation of item invariance across diagnostic groups. Nevertheless, a generic manual ability scale could be developed by adjusting and accounting for activities perceived differently in various disorders.

Motor and non-motor predictors of illness-related distress in Parkinson's disease

OBJECTIVE

To identify motor and non-motor symptoms independently associated with distress in Parkinson's disease (PD).

METHOD

Clinical and patient-reported data from 118 people with PD (mean age and PD-duration, 64 and 8 years) were analyzed regarding associations with patient-reported distress using multiple regressions (controlling for age).

RESULTS

Non-motor symptoms independently associated with distress were pain, fatigue, sleep, depression and anxiety (R(2), 0.81). The only significant motor aspect was mobility (R(2), 0.31). When considering both motor and non-motor symptoms, fatigue, pain, depression and sleep showed independent associations with distress (R(2), 0.76).

CONCLUSION

Distress in PD is primarily associated with non-motor features.

Psychometric performance of a generic walking scale (Walk-12G) in multiple sclerosis and Parkinson's disease

Walking difficulties are common in neurological and other disorders, as well as among the elderly. There is a need for reliable and valid instruments for measuring walking difficulties in everyday life since existing gait tests are clinician rated and focus on situation specific capacity. The Walk-12G was adapted from the 12-item multiple sclerosis walking scale as a generic patient-reported rating scale for walking difficulties in everyday life. The aim of this study is to examine the psychometric properties of the Walk-12G in people with multiple sclerosis (MS) and Parkinson's disease (PD). The Walk-12G was translated into Swedish and evaluated qualitatively among 25 people with and without various neurological and other conditions. Postal survey (MS, n = 199; PD, n = 189) and clinical (PD, n = 36) data were used to test its psychometric properties. Respondents considered the Walk-12G relevant and easy to use. Mean completion time was 3.5 min. Data completeness was good (<5% missing item responses) and tests of scaling assumptions supported summing item scores to a total score (corrected item-total correlations >0.6). Coefficient alpha and test-retest reliabilities were >0.9, and standard errors of measurement were 2.3-2.8. Construct validity was supported by correlations in accordance with a priori expectations. Results are similar to those with previous Walk-12G versions, indicating that scale adaptation was successful. Data suggest that the Walk-12G meets rating scale criteria for clinical trials, making it a valuable complement to available gait tests. Further studies involving other samples and application of modern psychometric methods are warranted to examine the scale in more detail.

Women with alcohol problems: the possible significance of personality clustering for treatment planning

INTRODUCTION AND AIMS

Establishing subgroups in clinical practice is important for treatment planning. The aim of the study was to cluster the study group subjects according to personality traits and psychological health variables and to establish possible differences in treatment outcome in terms of: (i) drinking outcomes (gram and number of drinking days); (ii) perceived physiological health; and (iii) use of treatment resources (length of time in treatment and number of visits) among 134 treatment-seeking women with alcohol problems in a clinical context, between the two clusters obtained.

DESIGN AND METHODS

Data were collected from 134 consecutive women at a Swedish clinic specialised in treating women with alcohol problems. A hierarchical cluster analysis was performed on the basis of self-rated personality scale scores and psychological health variables.

RESULTS

Two clusters were identified: one in which the women displayed personality and psychological health scores indicating problems (Cluster 1); and another where the women showed personality and psychological health scores within the norm range (Cluster 2). Alcohol consumption rates at the start of treatment were the same in both clusters. The consumption rates were also the same at the end of treatment for the cluster, showing a significant decrease in alcohol consumption in each. The Cluster 1 women, however, had a significantly higher number of visits at the clinic, and rated the consequences of their alcohol drinking as being significantly worse than Cluster 2 women.

DISCUSSION AND CONCLUSIONS

The importance of individual differences according to personality traits for treatment planning is discussed in terms of the need for variation in treatment time and methods.

Development and validation of participation and positive psychologic function measures for stroke survivors

OBJECTIVE

To evaluate the reliability and validity of Neurologic Quality of Life (NeuroQOL) item banks that assess quality-of-life (QOL) domains not typically included in poststroke measures.

DESIGN

Secondary analysis of item responses to selected NeuroQOL domains.

SETTING

Community.

PARTICIPANTS

Community-dwelling stroke survivors (n=111) who were at least 12 months poststroke.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Five measures developed for 3 NeuroQoL domains: ability to participate in social activities, satisfaction with participation in social activities, and positive psychologic function.

RESULTS

A single bank was developed for the positive psychologic function domain, but 2 banks each were developed for the ability-to-participate and satisfaction-with-participation domains. The resulting item banks showed good psychometric properties and external construct validity with correlations with the legacy instruments, ranging from .53 to .71. Using these measures, stroke survivors in this sample reported an overall high level of QOL.

CONCLUSIONS

The NeuroQoL-derived measures are promising and valid methods for assessing aspects of QOL not typically measured in this population.

Effects of method of translation of patient-reported health outcome questionnaires: a randomized study of the translation of the Rheumatoid Arthritis Quality of Life (RAQoL) Instrument for Sweden

AIMS

To compare two versions of a questionnaire translated using forward-backward (FB) translation and dual-panel (DP) methodologies regarding preference of wording and psychometric properties.

METHODS

The Rheumatoid Arthritis Quality of Life instrument was adapted into Swedish by two independent groups using FB and DP methodologies, respectively. Seven out of thirty resulting items were identical. Nonidentical items were evaluated regarding preference of wording by 23 bilingual Swedes, 50 people with rheumatoid arthritis (RA), and 2 lay panels (n = 11). Psychometric performance was assessed from a postal survey of 200 people with RA randomly assigned to complete one version first and the other 2 weeks later.

RESULTS

Preference did not differ among the 23 bilinguals (P = 0.196), whereas patients and lay people preferred DP over FB item versions (P < 0.0001). Postal survey response rates were 74% (FB) and 75% (DP). There were more missing item responses in the FB than the DP version (6.9% vs. 5.6%; P < 0.0001). Floor/ceiling effects were small (FB, 6.1/0%; DP, 4.4/0.7%) and reliability was 0.92 for both versions. Construct validity was similar for both versions. Differential item functioning by version was detected for five items but cancelled out and did not affect estimated person measures.

CONCLUSIONS

The DP approach showed advantages over FB translation in terms of preference by the target population and by lay people, whereas there were no obvious psychometric differences. This suggests advantages of DP over FB translation from the patients' perspective, and does not support the commonly held view that FB translation is the "gold standard."