Development of a multimorbidity illness perceptions scale (MULTIPleS).
ABSTRACT: BACKGROUND: Illness perceptions are beliefs about the cause, nature and management of illness, which enable patients to make sense of their conditions. These perceptions can predict adjustment and quality of life in patients with single conditions. However, multimorbidity (i.e. patients with multiple long-term conditions) is increasingly prevalent and a key challenge for future health care delivery. The objective of this research was to develop a valid and reliable measure of illness perceptions for multimorbid patients. METHODS: Candidate items were derived from previous qualitative research with multimorbid patients. Questionnaires were posted to 1500 patients with two or more exemplar long-term conditions (depression, diabetes, osteoarthritis, coronary heart disease and chronic obstructive pulmonary disease). Data were analysed using factor analysis and Rasch analysis. Rasch analysis is a modern psychometric technique for deriving unidimensional and intervally-scaled questionnaires. RESULTS: Questionnaires from 490 eligible patients (32.6% response) were returned. Exploratory factor analysis revealed five potential subscales 'Emotional representations', 'Treatment burden', 'Prioritising conditions', 'Causal links' and 'Activity limitations'. Rasch analysis led to further item reduction and the generation of a summary scale comprising of items from all scales. All scales were unidimensional and free from differential item functioning or local independence of items. All scales were reliable, but for each subscale there were a number of patients who scored at the floor of the scale. CONCLUSIONS: The MULTIPleS measure consists of five individual subscales and a 22-item summary scale that measures the perceived impact of multimorbidity. All scales showed good fit to the Rasch model and preliminary evidence of reliability and validity. A number of patients scored at floor of each subscale, which may reflect variation in the perception of multimorbidity. The MULTIPleS measure will facilitate research into the impact of illness perceptions on adjustment, clinical outcomes, quality of life, and costs in patients with multimorbidity.
Project description:BACKGROUND: Knowledge in natural sciences generally predicts study performance in the first two years of the medical curriculum. In order to reduce delay and dropout in the preclinical years, Hamburg Medical School decided to develop a natural science test (HAM-Nat) for student selection. In the present study, two different approaches to scale construction are presented: a unidimensional scale and a scale composed of three subject specific dimensions. Their psychometric properties and relations to academic success are compared. METHODS: 334 first year medical students of the 2006 cohort responded to 52 multiple choice items from biology, physics, and chemistry. For the construction of scales we generated two random subsamples, one for development and one for validation. In the development sample, unidimensional item sets were extracted from the item pool by means of weighted least squares (WLS) factor analysis, and subsequently fitted to the Rasch model. In the validation sample, the scales were subjected to confirmatory factor analysis and, again, Rasch modelling. The outcome measure was academic success after two years. RESULTS: Although the correlational structure within the item set is weak, a unidimensional scale could be fitted to the Rasch model. However, psychometric properties of this scale deteriorated in the validation sample. A model with three highly correlated subject specific factors performed better. All summary scales predicted academic success with an odds ratio of about 2.0. Prediction was independent of high school grades and there was a slight tendency for prediction to be better in females than in males. CONCLUSIONS: A model separating biology, physics, and chemistry into different Rasch scales seems to be more suitable for item bank development than a unidimensional model, even when these scales are highly correlated and enter into a global score. When such a combination scale is used to select the upper quartile of applicants, the proportion of successful completion of the curriculum after two years is expected to rise substantially.
Project description:To evaluate the psychometric properties of the Adult Strabismus-20 (AS-20)- a health-related quality of life (HRQoL) questionnaire in adults with strabismus, and if flawed, to revise the AS-20 and its subscales creating valid measurement scales.584 adults (meanage, 27.5 years) with strabismus were recruited from an outpatient clinic at a South Indian tertiary eye care centre and were administered the AS-20 questionnaire.The AS-20 was translated and back translated into two Indian languages. The AS-20 and its two 10-item subscales - 'psychosocial' and 'function'were assessed separately for fit to the Rasch model, including an assessment of the rating scale, unidimensionality (by principal components analysis), measurement precision by person separation reliability, PSR, targeting, and differential item functioning (DIF; notable > 1.0 logits).Response categories were not used as intended, thereby, required re-organization and reducing their number from 5 to 3. The AS-20 had adequate measurement precision (PSR = 0.87) but lacked unidimensionality; however, deletion of the six multi-dimensionality causing items and an additional three misfitting items resulted in 11-item unidimensional questionnaire (AS-11). Two items failed to satisfy the model expectations in the 'psychosocial' subscale and were deleted - resulting in an 8-item unidimensional scale with adequate PSR (0.81) and targeting (0.23 logits). One item misfit in the 'function' subscale and was deleted-resulting in a 9 item Rasch-revised unidimensional subscale with acceptable PSR (0.80) and targeting (0.97 logits).None of the items displayed notable DIF by age, gender and level of education.The AS-11 and its two Rasch-revised subscales - 8-item psychosocial and 9-item function subscale may be more appropriate than the original AS-20 and its two 10-item subscales for use as unidimensional measures of HRQoL in adults with strabismus in India. Further work is required to establish the validity of the revised rating scale.
Project description:BACKGROUND:A proactive person-centred care process is advocated for people with multimorbidity. To that aim, general practitioners may benefit from support in the identification of high-need patients, i.e. patients who are high or suboptimal users of health services and/or have a poor quality of life. To develop such support, we examined whether knowledge about patients' illness perceptions and personal resources to manage their health and care is useful to identify high-need patients among multimorbid general practice populations. METHODS:Survey data, collected in 2016 and 2017, of 601 patients with two or more chronic diseases (e.g. COPD, diabetes, Parkinson's disease) registered with 40 general practices in the Netherlands were analysed by logistic regression analysis to predict frequent contact with the general practice, contact with general practice out-of-office services, unplanned hospitalisations and poor health related quality of life. Patients' illness perceptions and personal resources (education, health literacy, mastery, mental health status, financial resources, social support) were included as predictors. RESULTS:The four outcomes were only weakly associated among themselves (Phi .07-.19). Patients' illness perceptions and personal resources were of limited value to predict potentially suboptimal health service use, but they were important predictors of health related quality of life. Patients with a poor health related quality of life could be identified by their previously reported illness perceptions (attributing many symptoms to their chronic conditions (B?=?1.479, P <?.001), a high level of concern (B?=?0.844, P =?.002) and little perceived control over their illness (B?=?-0.728, P =?.006)) combined with an experienced lack of social support (B?=?-0.527, P =?.042) and a poor mental health status (B?=?-0.966, P =?.001) (sensitivity 80.7%; specificity 68.1%). CONCLUSIONS:Multimorbid patients who frequently contact the general practice, use general practice out-of-office services, have unplanned hospitalisations or a poor health related quality of life are largely distinct high-need subgroups. Multimorbid patients at risk of developing a poor quality of life can be identified from specific illness beliefs, a poor mental health status and unmet social needs.
Project description:BACKGROUND:King's Sarcoidosis Questionnaire (KSQ) is a novel, validated, health-related quality of life questionnaire on sarcoidosis with 5 scales and 29 items. For future multinational observational and interventional studies on sarcoidosis, a validated German version of the KSQ is needed. The objective of our study is to translate the original KSQ and develop a German version possessing good psychometric properties and with as few modifications as possible. METHODS:We translated the KSQ into German, tested it in structured interviews in sarcoidosis patients, and asked consecutive patients in an outpatient clinic to complete it. We relied on the KSQ's original version to achieve its psychometric properties in the German version. Structural validity, internal consistency, construct validity, and fit to Rasch model were assessed. Our procedure's logic meant that in the first step we optimized the item selection in the German version to maximize its psychometric quality. In step two, we assessed the unmodified version's properties in comparison to the modified version's. RESULTS:One hundred ninety-four patients with sarcoidosis were included and completed the questionnaires. Due to ambiguous factor loadings, four items of the scale "General Health Status" had to be eliminated. Another item was excluded to ensure the Rasch model fit. This modified, 24-item version of the KSQ shows acceptable Rasch model fit and good model fit in confirmatory factor analyses (TLI?=?0.90, CFI?=?0.91, RMSEA?=?0.08). Cronbach's Alpha ranges from 0.82 to 0.91. Several hypotheses concerning construct validity (e.g., correlations with SF-36) are confirmed or partly confirmed. The measurement properties of the original unmodified version are similar in their construct validity and internal consistency; however, we were unable to confirm structural validity and fit to the Rasch model in the original version. CONCLUSIONS:We translated and validated the German KSQ and report good psychometric properties. The reduced 24-item version has the advantage that all scales are unidimensional and fulfil the requirements of the Rasch model, ensuring its benefits. The original 29-item version, on the other hand, allows us to compare German data to international data however, at the price, of less structural validity and the lack of fit to the Rasch model. TRIAL REGISTRATION:This study was registered in the German Clinical Trials Register (reference number DRKS00010072 ). Registered January 2016.
Project description:BACKGROUND:Existing instruments for measuring mobility are inadequate for accurately assessing older people across the broad spectrum of abilities. Like other indices that monitor critical aspects of health such as blood pressure tests, a mobility test for all older acute medical patients provides essential health data. We have developed and validated an instrument that captures essential information about the mobility status of older acute medical patients. METHODS:Items suitable for a new mobility instrument were generated from existing scales, patient interviews and focus groups with experts. 51 items were pilot tested on older acute medical inpatients. An interval-level unidimensional mobility measure was constructed using Rasch analysis. The final item set required minimal equipment and was quick and simple to administer. The de Morton Mobility Index (DEMMI) was validated on an independent sample of older acute medical inpatients and its clinimetric properties confirmed. RESULTS:The DEMMI is a 15 item unidimensional measure of mobility. Reliability (MDC(90)), validity and the minimally clinically important difference (MCID) of the DEMMI were consistent across independent samples. The MDC(90) and MCID were 9 and 10 points respectively (on the 100 point Rasch converted interval DEMMI scale). CONCLUSION:The DEMMI provides clinicians and researchers with a valid interval-level method for accurately measuring and monitoring mobility levels of older acute medical patients. DEMMI validation studies are underway in other clinical settings and in the community. Given the ageing population and the importance of mobility for health and community participation, there has never been a greater need for this instrument.
Project description:BACKGROUND:Person-centred care is the bedrock of modern dementia services, yet the evidence-base to support its implementation is not firmly established. Research is hindered by a need for more robust measurement instruments. The 14-item Person-Centred Climate Questionnaire - Staff version (PCQ-S) is one of the most established scales and has promising measurement properties. However, its construction under classical test theory methods leaves question marks over its rigour and the need for evaluation under more modern testing procedures. METHODS:The PCQ-S was self-completed by nurses and other care staff working across nursing homes in 35 Swedish municipalities in 2013/14. A Rasch analysis was undertaken in RUMM2030 using a partial credit model suited to the Likert-type items. Three subscales of the PCQ-S were evaluated against common thresholds for overall fit to the Rasch model; ordering of category thresholds; unidimensionality; local dependency; targeting; and Differential Item Functioning. Three subscales were evaluated separately as unidimensional models and then combined as subtests into a single measure. Due to large number of respondents (n?=?4381), two random sub-samples were drawn, with a satisfactory model established in the first ('evaluation') and confirmed in the second ('validation'). Final item locations and a table converting raw scores to Rasch-transformed values were created using the full sample. RESULTS:All three subscales had disordered thresholds for some items, which were resolved by collapsing categories. The three subscales fit the assumptions of the Rasch model after the removal of two items, except for subscale 3, where there was evidence of local dependence between two items. By forming subtests, the 3 subscales were combined into a single Rasch model which had satisfactory fit statistics. The Rasch form of the instrument (PCQ-S-R) had an adequate but modest Person Separation Index (<?0.80) and some evidence of mistargeting due to a low number of 'difficult-to-endorse' items. CONCLUSIONS:The PCQ-S-R has 12 items and can be used as a unidimensional scale with interval level properties, using the nomogram presented within this paper. The scale is reliable but has some inefficiencies due to too few high-end thresholds inhibiting discrimination amongst populations who already perceive that person-centred care is very good in their environment.
Project description: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.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.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.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.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.
Project description:BACKGROUND: The SF-36 physical functioning scale (PF-10) and the Health Assessment Questionnaire disability index (HAQ-DI) are the most frequently used instruments for measuring self-reported physical function in rheumatoid arthritis (RA). The objective of this study was to develop a crosswalk between scores on the PF-10 and HAQ-DI in RA. METHODS: Item response theory (IRT) methods were used to co-calibrate both scales using data from 1791 RA patients. The appropriateness of a Rasch-based crosswalk was evaluated by comparing it with crosswalks based on a two-parameter and a multi-dimensional IRT model. The accuracy of the final crosswalk was cross-validated using baseline (n = 532) and 6-month follow-up (n = 276) data from an independent cohort of early RA patients. RESULTS: The PF-10 and HAQ-DI adequately fit a unidimensional Rasch model. Both scales measured a wide range of functioning, although the HAQ-DI tended to better target lower levels of functioning. The Rasch-based crosswalk performed similarly to crosswalks based on the two-parameter and multidimensional IRT models. Agreement between predicted and observed scale scores in the cross-validation sample was acceptable for group-level comparisons. The longitudinal validity in discriminating between disease response states was similar between observed and predicted scores. CONCLUSION: The crosswalk developed in this study allows for converting scores from one scale to the other and can be used for group-level analyses in patients with RA.
Project description:<h4>Background</h4>The Psychiatric Out-Patient Experiences Questionnaire (POPEQ) is an 11-item core measure of psychiatric out-patients experiences of the perceived outcome of the treatment, the quality of interaction with the clinician, and the quality of information provision. The POPEQ was found to have evidence for reliability and validity following the application of classical test theory but has not previously been assessed by Rasch analysis.<h4>Methods</h4>Two national postal surveys of psychiatric outpatients took place in Norway in 2004 and 2007. The performance of the POPEQ, including item functioning and differential item functioning, was assessed by Rasch analysis. Principal component analysis of item residuals was used to assess the presence of subdimensions.<h4>Results</h4>6,677 (43.3%) and 11,085 (35.2%) psychiatric out patients responded to the questionnaire in 2004 and 2007, respectively. All items in the scale were retained after the Rasch analysis. The resulting scale had reasonably good fit to the Rasch model. The items performed the same for the two survey years and there was no differential item functioning relating to patient characteristics. Principal component analysis of the residuals confirmed that the measure to a high degree is unidimensional. However, the data also reflects three potential subscales, each relating to one of the three included aspects of health care.<h4>Conclusions</h4>The POPEQ had excellent psychometric properties and Rasch analysis further supported the construct validity of the scale by also identifying the three subdimensions originally included as components in the instrument development. The 11-item instrument is recommended in future research on psychiatric out-patient experiences. Future development may lead to the construction of more precise measures of the three subdomains that the POPEQ is based on.
Project description:Middle-income countries are facing a growing challenge of adequate health care provision for people with multimorbidity. The objectives of this study were to explore the distribution of multimorbidity and to identify patterns of multimorbidity in the Brazilian general adult population. Data from 60202 adults, aged ?18 years that completed the individual questionnaire of the National Health Survey 2013 (Portuguese: "Pesquisa Nacional de Saúde"-"PNS") was used. We defined multimorbidity as the presence of two or more chronic conditions, including self-reported diagnoses and responses to the 9-item Patient Health Questionnaire for depression. Multivariate Poisson regression analyses were used to explore relationship between multimorbidity and demographic factors. Exploratory tetrachoric factor analysis was performed to identify multimorbidity patterns. 24.2% (95% CI 23.5-24.9) of the study population were multimorbid, with prevalence rate ratios being significantly higher in women, older people and those with lowest educational level. Multimorbidity occurred earlier in women than in men, with half of the women and men aged 55-59 years and 65-69 years, respectively, were multimorbid. The absolute number of people with multimorbidity was approximately 2.5-fold higher in people younger than 65 years than older counterparts (9920 vs 3945). Prevalence rate ratios of any mental health disorder significantly increased with the number of physical conditions. 46.7% of the persons were assigned to at least one of three identified patterns of multimorbidity, including: "cardio-metabolic", "musculoskeletal-mental" and "respiratory" disorders. Multimorbidity in Brazil is as common as in more affluent countries. Women in Brazil develop diseases at younger ages than men. Our findings can inform a national action plan to prevent multimorbidity, reduce its burden and align health-care services more closely with patients' needs.