Psychometric evaluation of the revised Illness Perception Questionnaire (IPQ-R) in cancer patients: confirmatory factor analysis and Rasch analysis

What do cancer survivors believe caused their cancer? A secondary analysis of cross-sectional survey data

PURPOSE

Given that risk reduction and healthy lifestyles can prevent 4 in 10 cancers, it is important to understand what survivors believe caused their cancer to inform educational initiatives.

METHODS

In this secondary analysis, we analyzed cancer survivor responses on the Causes Subscale of the Revised Illness Perception Questionnaire, which lists 18 possible causes of illness and a free text question. We used descriptive statistics to determine cancer survivors' agreement with the listed causes and conducted separate partial proportional odds models for the top three causes to examine their associations with sociodemographic and clinical characteristics. Content analysis was used to examine free text responses.

RESULTS

Of the 1,001 participants, most identified as Caucasian (n = 764, 77%), female (n = 845, 85%), and were diagnosed with breast cancer (n = 656, 66%). The most commonly believed causes of cancer were: stress or worry (n = 498, 51%), pollution in the environment (n = 471, 48%), and chance or bad luck (n = 412, 42%). The associations of sociodemographic and clinical variables varied across the models. Free text responses indicated that hereditary and genetic causes (n = 223, 22.3%) followed by trauma and stress (n = 218, 21.8%) and bad luck or chance (n = 79, 7.9%) were the most important causes of cancer.

CONCLUSIONS

Study results illuminate cancer survivors' beliefs about varying causes of their cancer diagnosis and identify characteristics of survivors who are more likely to believe certain factors caused their cancer. Results can be used to plan cancer education and risk-reduction campaigns and highlight for whom such initiatives would be most suitable.

Validity of the Brief Illness Perception Questionnaire in people with knee pain: a Rasch analysis

OBJECTIVE

The Brief Illness Perception Questionnaire (B-IPQ) is a frequently used measure of illness perception (IP). The aim of this study was to explore the psychometric properties of the questionnaire when used in elderly people with knee pain.

METHOD

Based on data from the Frederiksberg Cohort on elderly people reporting knee pain (N = 836), the psychometric properties of the eight B-IPQ items (1 'Consequences', 2 'Timeline', 3 'Personal control', 4 'Treatment control', 5 'Identity', 6 'Concern', 7 'Coherence', and 8 'Emotions') were analysed using Rasch analysis to establish whether the questionnaire provides reliable and valid measures of IP.

RESULTS

Threshold disordering was found on the 1-10 rating scale in all items. When rescaling to a 0-2 rating scale, disordering was resolved in six items. Item goodness-of-fit analyses revealed that two items displayed underfit misfit and four items overfit misfit; hence, the B-IPQ does not present unidimensionality. The person separation index indicated that items separate respondents into only two IP levels. Finally, floor and ceiling effects were found, indicating that the B-IPQ may not fully describe the extent of IP in this population.

CONCLUSION

The 1-10 rating scale used in the Danish B-IPQ targeting knee pain is suboptimal, while a 0-2 scale improves the psychometric properties of the scale. The B-IPQ does not present unidimensionality and the use of a sum score is therefore not recommended when assessing IP. The B-IPQ may not cover the extent of IP in elderly people with knee pain.

Fit to the rasch model of the FEEL-KJ Spanish adaptation

Background

In recent decades, scientific production related to Emotional Regulation (ER) has increased significantly. Deficits in ER have been linked to various mental health problems. The aim of this work is to evaluate the Spanish adaptation of the Feel-Kj scale to the RASCH model.

Method

Children from 9 to 16 years old took part of this study. One hundred and eighteen children between 9 and 16 years old and one hundred and fifteen from 13 to 16. The 254 participants were attending 25 schools located in de Valencian Community in Spain.

Results

Both infit and outfit MNSQ statistics provided evidence for the construct validity of the FEEL-KJ questionnaire. The infit and outfit mean values (1.01 and 1.02, respectively) were close to the perfect fit value of 1.

Conclusions

From these results it can be sensed that the FEEL-KJ will be a valid and reliable instrument to apply in the Spanish speaking population, although it is necessary to make some minor adjustments in terms of translation.

Development and validation of assessment instrument for the perception and attitude toward tuberculosis among the general population in Indonesia: a Rasch analysis of psychometric properties

Introduction

Tuberculosis (TB)-related knowledge is an important evaluation metric for health education interventions. Factor analysis is limited when used on ordinal scales and does not provide in-depth item function examinations, whereas Rasch analysis addresses these limitations and offers potential advantages such as generalizability, testing of unidimensionality, producing an ordered set of items, and identifying poorly functioning items. Therefore, this research aims to develop a reliable and valid measure of perception and attitude toward TB (PATT) for public application use Rasch Analysis.

Methods

A questionnaire-based survey was conducted on the Indonesian general population using the Google Form platform. Rasch analysis was then employed to examine the psychometric properties and develop the final items of PATT.

Results

Experts from across the TB community participated in the PATT development, producing an initial scale of 16 items. Up to 1,616 participants completed the PATT questionnaire, where 74.8% were female, and 5% had a TB history. The final unidimensional 16-item scale has an item reliability of 1.00 for the two components (perception and attitude), a person reliability index of 0.87 and 0.60, as well as a Cronbach's test reliability of 0.88 and 0.88 for perception and attitude, respectively.

Conclusion

The PATT is a unidimensional scale with good construct validity and internal consistency. It has the potential to be useful for the assessment of TB perception and attitude in research and clinical practice.

Psychometric approach to evaluate periodontal disease using Revised Illness Perception Questionnaire

Introduction:

Illness perception is the cognitive representation of an illness, which determines how a person responds to it. The Revised Illness Perception Questionnaire (IPQ-R) assesses seven components of illness representation in various chronic diseases, but queries prevail about its factor structure. The study assesses the components of illness representation in patients with chronic periodontitis.

Materials and Methods:

A total of 625 voluntary, consecutive dental patients with a clinical diagnosis of periodontitis were recruited into the study. The Hindi version of IPQ-R was used, consisting of three parts-identity scale, structured scale, and perceived causes of the patient's ailment.

Results:

Of the 625 participants, 44.0% reported cyclical disease pattern, 30.4% said their disease was a mystery. Only 1.6% predicted it to remain throughout their life. A total of 44.0% of participants reported the disease to impact their day-to-day life severely. A significant difference was observed between males and females across seven components of IPQ-R. While 21.6% of participants attributed stress to be a major cause for their diseased state, 20.8% reported workload to be a major cause, but 42.4% attributed poor medical care in the past to be a major cause for their state.

Conclusions:

A sensible approach to treating a disease is to measure the patient's illness perception and target specific interventions accordingly. It would be cost-effective and break misconceptions about diseases in patients, ultimately providing them with better overall health and satisfaction.

Psychometric characteristics of the Revised Illness Perception Questionnaire (IPQ-R) in adults with sickle cell disease

OBJECTIVE

Sickle cell disease (SCD) is the most frequent monogenic disease worldwide. Psychological and behavioural factors are often reported as playing a significant role in predicting SCD health outcomes. When focusing on adaptation to a specific health condition and its treatment, the Common Sense Model of Health and Illness (CSM) has proven to be of heuristic value. In other health conditions, illness outcomes are directly influenced by illness perception. Therefore, the aim of this study is to explore the psychometric proprieties of the Revised Illness Perception Questionnaire (IPQ-R).

DESIGN

We performed a cross-sectional assessment on 517 adult patients with sickle cell disease and collected the results of 406 IPQ-R. With these data, we verified the factor structure of the Belief scale and proposed modifications to improve its fit to the data with a confirmatory factor analysis. In addition, we explored the factorial structure of the Causal attribution scale with an exploratory factor analysis.

RESULTS

The initial model showed poor fit with the data. After structural modifications, elimination of two items with a low loading (model 2), covariance added between items (model 3) and items reallocation (model 4), the last model proposed presented a correct fit with the data. Before doing this model specification, we reviewed and compiled the nine studies that explored the psychometric properties of the IPQ-R in order to highlight all the modifications made by the other authors who have adapted the IPQ-R to a specific population and to allow a comparison with our own modifications.

CONCLUSION

Considering previous findings, this research suggests further work is needed on the structure of the dimensions of the IPQ-R.

Polish Adaptation and Validation of the Revised Illness Perception Questionnaire (IPQ-R) in Cancer Patients

The article presents findings from three studies designed to validate and culturally adapt the Polish version of the Revised Illness Perception Questionnaire (IPQ-R), a measure of the cognitive and emotional components of illness representations among oncology patients. The tool is conceptually based on Leventhal’s Self-Regulatory Model (Leventhal et al., 1984, 2001). The results of the study 1 (n = 40) show that it can be successfully used in a Polish cultural context as a reliable equivalent to its original English version (Moss-Morris et al., 2002). Analyses conducted in Study 2 (n = 318) provided good evidence for construct and criterion validity as well as the internal reliability of the IPQ-R subscales. Study 3 (n = 54) revealed that the IPQ-R subscales present good test–retest reliability. Overall, the results show that the Polish version of the IPQ-R provides a comprehensive and psychometrically acceptable assessment of the representation of cancer and can be reliably used in studies involving Polish oncology patients.

Rasch Analysis of Authentic Evaluation of Young Children's Functioning in Classroom Routines

This study evaluated the functioning of children in early childhood education classroom routines, using the 3M Functioning in Preschool Routines Scale. A total of 366 children aged 36 to 70 months and 22 teachers from six early childhood education centers in Spain participated in the study. The authors used the Rasch model to determine the item fit and the difficulty of the items in relation to children's ability levels in this age range. The Rasch Differential Item Functioning (DIF) analysis by child age groups showed that the item difficulty differed according to the children's age and according to their levels of competence. The results of this study supported the reliability and validity of the 3M scale for assessing children's functioning in preschool classroom routines. A few items, however, were identified as needing to be reworded and more difficult items needed to be added to increase the scale difficulty level to match the performance of children with higher ability levels. The authors introduced the new and reworded items based on the results of this study and the corresponding ICF codes per item. Moreover, the authors indicate how to use the ICF Performance Qualifiers in relation to the 3M scale response categories for developing a functioning profile for the child.

HADS-depression score is a mediator for illness perception and daily life impairment in Takayasu's arteritis

INTRODUCTION/OBJECTIVES

The aim of this study was to evaluate the relationships among the disease activity, illness perception, daily life performance, anxiety and depression status as potential mediators in Takayasu's arteritis (TAK) patients.

METHOD

In this cross-sectional study, 77 TAK patients were included. Data were collected by a clinical examination and a structured questionnaire regarding patient reported outcome measures (PROMs). Indian Takayasu's Arteritis Activity Score2010 (ITAS2010) was used to assess the disease activity (0: inactive vs ≥ 1: active). Illness Perception Questionnaire-Revise (IPQ-R), Work Productivity and Activity Impairment (WPAI) and Hospital Anxiety and Depression Scale (HADS) as PROMs were used to understand for the patient' perspective. After preliminary analysis, complex relationships among these variables were evaluated by mediation analyses in the study.

RESULTS

WPAI-Daily impairment score, HADS-A and HADS-D scores as well as IPQ-R Consequence score were found be high in active TAK patients (p = 0.008; p = 0.001; p = 0.031; p = 0.001). HADS-D score was also correlated with WPAI-Daily impairment score and IPQ-R Consequence score (p < 0.05). In mediation analysis, IPQ-R Consequence score was directly mediated by disease activity (ITAS2010) (p = 0.0173) and indirectly mediated through HADS-D score (p = 0.0003). Similarly, HADS-D score was associated with poor WPAI-Daily impairment score in the mediation analysis in the indirect path (p = 0.0069). Disease activity (ITAS2010) also increased WPAI-Daily impairment score in direct path (p = 0.043).

CONCLUSIONS

Active TAK patients perceived their illness more seriously and experienced more impairment in their daily life. Depression status as the mediator influenced them poorly. These interactions could give clues to improve PROMs in the clinical practice. Key Points •IIness perception, disease activity, mental status and daily life performance, assessed as patient-reported outcome measures, have a complex relationship in Takayasu's arteritis. •IPQ-R Consequence score, WPAI-Daily impairment score, HADS-Depression and HADS-Anxiety scores were found be high in active TAK patients. •In mediation analysis, IPQ-R Consequence score was directly mediated by disease activity and indirectly mediated through HADS-D score. Similarly, disease activity increased WPAI-Daily impairment score in direct and HADS-D in indirect paths.

The Illness Belief Network Questionnaire: Development and Evaluation of a Psychosomatic Assessment Tool

Objective: Patients’ beliefs and emotions toward an illness can influence their coping responses, illness behaviors, adherence to treatment, quality of life, and even the psychoneuroimmune responses. The aim of present study was to develop and validate a novel questionnaire assessing both rational and irrational beliefs of patients regarding their illness.

Method: In a cross sectional methodological study, the items of the Illness Belief Network (IBN) were developed regarding patients and clients’ opinions about and attribution of their disease extracted from 400 clinical interviews and were coded based on Leventhal’s self-regulation model. An expert panel coded the items. A total of 400 patients with different medical conditions completed the questionnaire. Participants additionally rated the Illness Perceptions Questionnaire in its revised form (IPQ-R) to assess convergent validity. Construct validity was examined by conducting exploratory and confirmatory factor analysis. The Cronbach alpha and Intracluster Correlation Coefficient (ICC) were used for examining Internal consistency and test-retest reliability of the IBN.

Results: The IBN questionnaire was finalized with 84 items, and the results of factor analysis revealed 5 factors: psychosocial causes, environmental causes, control, meaning, and consequence/timeline; extracted factors were confirmed by confirmatory factor analysis. Cronbach’s α coefficient for scale was 0.92 and it ranged from 0.79 to 0.89 for the subscales. IBN indicated excellent test-retest reliability results based on ICC 0.842(95%CI: 0.798-0.846). The correlation coefficients of all items exceeded the prespecified acceptable value of 0.40, indicating satisfactory item discriminant validity, and correlation between IBN and IPQ-R subscales were statistically significant (all p values < 0.01), indicating acceptable convergent validity.

Conclusion: The IBN questionnaire is a valid and reliable phenomenological, non-judging, and clinical tool to assess patient’s rational and irrational or faith-based beliefs about the illness. This tool can be used to improve doctor-patient communication by exploring the complex nature of human thinking.

Adaptation and psychometric testing of the Chinese version of the Revised Illness Perception Questionnaire for cervical cancer patients

PURPOSE

Illness perception is an important factor that influences psychological distress, coping behaviors, and illness outcomes, and this factor is often assessed by the Revised Illness Perception Questionnaire (IPQ-R). Data regarding illness perception among cervical cancer patients are limited, especially in China. The study aimed to adapt and psychometrically test the Chinese version of the IPQ-R for Cervical Cancer (CIPQ-R-CC).

METHODS

This was a methodological study. Before the survey, the identity and causal subscales (originally 14 and 18 items, respectively) were adapted. Data were collected from 220 cervical cancer patients (N = 220) from June 2018 to February 2019. Psychometric properties were assessed using explanatory factor analysis, confirmatory factor analysis, Pearson correlation coefficients, one-way analysis of variance, t-tests and Cronbach's alpha coefficients.

RESULTS

Eight identity items and twenty-six causal items were included in the CIPQ-R-CC, which showed acceptable content validity (I-CVI = 0.78-1.00, S-CVI = 0.97-0.99). A five-factor solution was obtained from the cause subscale by explanatory factor analysis, and these factors explained 60.19% of the total variance. For Part III of the CIPQ-R-CC, after deleting nine items and respecifying five error covariances, the proposed seven-factor model was confirmed. There were low to moderate correlations between the latent factors (r＜0.52). Known-group validity was demonstrated in some groups with different demographic characteristics. The Cronbach's alpha coefficients were also acceptable (0.60-0.88).

CONCLUSION

The CIPQ-R-CC is a reliable and valid tool for assessing illness perception among Chinese cervical cancer patients. Future studies are needed to verify its factor structure and to confirm its theoretical connotation.

Predicting Pain Trajectories in the One Year Following Breast Cancer Diagnosis-An Observational Study

The impact of psychosocial vulnerability on pain in the year following breast cancer diagnosis has been little studied. To identify a score of psychosocial vulnerability (cognitive, emotional, quality of life and precariousness parameters) as a predictor of a pain trajectory, we conducted an observational prospective study and included women with newly diagnosed breast cancer. One year follow-up with 3 visits (day of breast cancer diagnosis; 6 and 12 months) aimed to identify distinct pain-time trajectories. Baseline psychosocial vulnerability was characterized by z-score transformation, a higher score representing a more vulnerable patient. A total of 89 patients were included (59.3 ± 10.7 years). Two trajectories of pain were identified-"Transient Pain trajectory" (TP) (39/89 patients) and "Persistent Pain trajectory" (PP) (50/89). A significant difference of pain over time between trajectories (PP vs. TP at 6 months: 2.23 ± 0.23 vs. 0.27 ± 0.09, p < 0.001) was observed. Psychosocial vulnerability showed a large effect size (d, -0.82; 95% CI, -1.25 to -0.38; p < 0.001) and a higher score in "Persistent pain trajectory" (PP vs. TP: 0.12 ± 0.36 vs. -0.14 ± 0.26, p < 0.001). A predictive vulnerability marker of pain development is proposed and could be used at cancer diagnosis to orientate the care pathway of patients experiencing breast cancer.

Psychometric evaluation of the illness perception questionnaire for schizophrenia in a Chinese population

BACKGROUND

Illness perceptions have been associated with patients' reactions to health threats and further health outcomes. The Illness Perception Questionnaire for Schizophrenia (IPQS)¹ has been applied in different contexts. However, the validity and reliability of IPQS remain unknown in mainland China.

AIMS AND OBJECTIVES

To test the psychometric properties of the Chinese version of IPQS in mainland China.

DESIGN

A cross-sectional survey.

METHODS

A total of 200 community-dwelling patients with schizophrenia were surveyed in Beijing, China. The validity and reliability of the instrument were tested. As well as demographic data, the IPQS and the Knowledge About Schizophrenia Test (KAST)² were also administered.

RESULTS

Factor analysis was utilised to refine the factor structure of the IPQS. The difference between IPQS and KAST denoted the discriminant validity. The subscale scores among patients of different illness duration, educational attainment, and medication adherence in the past two years were significantly different (P＜0.05), indicating the known-group validity of the IPQS. Except for 'personal control' and 'burdensome effect', other subscales were internally consistent. Most of the subscales proved stable over a four-week period.

CONCLUSION

The Chinese version of IPQS can be used, with some refinements, to assess illness perceptions about schizophrenia for patients in future studies. This will provide empirical evidence for its generalizability and clinical utility and provide deeper insight into Chinese patients' illness perceptions about schizophrenia.

Recruitment via social media: advantages and potential biases

Background

Adolescent and young adult (AYA) cancer survivors are under-represented in research. Social media is increasingly used for recruitment given its ability to reach large audiences. Differences in participant characteristics and potential biases due to recruitment source are not well understood.

Purpose

This study aimed to: (a) compare recruitment strategies (hospital-based v. social media) in enrollment metrics, and (b) among enrolled participants, evaluate group differences in patient characteristics and patient reported outcomes (PROs).

Methods

Preliminary data from a cancer and fertility study with female AYAs were evaluated. Hospital-based recruitment used electronic medical records (EMR) to identify eligible patients. Social media recruitment involved posting on partner organizations’ social media outlets. PROs included validated measures related to the parent study. Descriptive statistics evaluated recruitment metrics. Independent samples t-tests and chi-square identified differences in participant characteristics and PROs based on recruitment.

Results

Social media yielded a higher enrollment rate (37%; n = 54/146) compared with hospital-based recruitment (7%; n = 21/289) and required fewer study resources. Compared with hospital-based recruitment, participants from social media were more likely to be White (p = 0.01), with a longer time since treatment (p = 0.03); and reported higher levels of reproductive concern (p = 0.004) and negative mood (p = 0.02), and more negative illness perceptions (ps < 0.05).

Conclusion

Recruitment via social media may be a more effective and efficient strategy compared with hospital-based methods. However, group differences were identified that could bias findings and limit generalizability. Advantages of social media should be considered with an understanding of how methodology may impact enrollment and results.

Does illness perception associate with disease symptoms in Behçet's disease?

This study aims to assess the relationship between illness perception and disease course and symptoms in Behçet disease (BD). One hundred ten consecutive BD patients (F/M 50/60, mean age 38.5 ± 9.88 years) and 57 patients with Psoriasis as a disease control group (F/M 28/29, mean age 48.12 ± 15.52) are included in this cross-sectional study. Illness perception is evaluated using a revised version of the Illness Perception Questionnaire (IPQ-R). In IPQ-R, the identity score reflecting the number of symptoms is higher in BD patients with musculoskeletal involvement than the others (6.77 ± 2.91 vs. 5.08 ± 3.3, respectively, p = 0.007). The consequences score for musculoskeletal involvement (19.52 ± 7.03) and timeline (acute/chronic) score for eye involvement (26.67 ± 4.32) are also higher compared to patients without them (16.37 ± 5.82 and 22.09 ± 8.68) (p = 0.011 and p = 0.038), reflecting negative beliefs about the illness. The score of psychological attribution is higher in patients with psoriasis than BD (p = 0.039), whereas the other subgroup scores are lower in patients with psoriasis compared to those of BD (p < 0.05). This study provides a patient's perspective in the disease management process of BD using the IPQ-R questionnaire. A patient's own personal beliefs and emotional responses to their symptoms might affect the outcome measures, especially with musculoskeletal symptoms and eye involvement in BD. However, psychological attribution is found to be a prominent issue in psoriasis.

Psychometric Characteristics of the Revised Illness Perception Questionnaire (IPQ-R) in People Undergoing Weight Loss Surgery

The Illness Perception Questionnaire-Revised (IPQ-R) has been used extensively across many health conditions to measure patient illness and treatment perceptions. The constructs have an association with treatment adaptation and adherence which, in turn, are considered core factors involved in bariatric surgery outcome. This study examines the factorial validity and internal reliability of a modified (IPQ-R) in bariatric surgery candidates. After wording modifications, participants (N = 310) completed the IPQ-R as part of standard pre-surgery assessments. After removal of two items, confirmatory factor analysis (CFA) supported the original 7-factor solution of the Beliefs scale, with good to marginal subscale internal consistency. Exploratory factor analysis (EFA), with two items removed only partially supported the original 5-factor Causal Attributions scale. Internal consistency was unacceptably low for two subscales. Further research is needed to generate new items which better fit the IPQ-R to this population before research can explore the relevance of illness perceptions.

The perceived severity of a disease and the impact of the vocabulary used to convey information: using Rasch scaling in a simulated oncological scenario

BACKGROUND

Healthcare staff should be aware of the importance that patients may attach to the words that are used to convey information. This is relevant in terms of the patients' understanding. Modeling how people understand the information conveyed in a medical context may help health practitioners to better appreciate the patients' approach.

PURPOSE

1) Analyze the participants' self-reported perception of the type of information provided in an oncological scenario in terms of three dimensions: impairment to their health, risks associated with the disease itself and commitment required to undergo the treatment; and 2) show the benefits of using Rasch scaling for the analysis of the data. Starting from a survey, Rasch scaling produces a unidimensional logit-interval scale relating to the extent to which each item conveys a latent dimension. These were related to structure, in particular concerning communication by means of opposite vs. unipolar language.

SUBJECTS AND METHODS

The participants rated 82 items of information in a questionnaire regarding their perception of impairment to their health (H) and the risks (R) and commitment relating to the treatment prescribed (T).

RESULTS

The scaling produced an item bank for healthcare staff to consult in order to estimate the importance the recipient would be likely to attach to the vocabulary used and the likely impact of the information in terms of the patient's condition. Furthermore, the use of opposites was generally associated with a clearer impression of whether the information given was generally only very negative or slightly negative, whereas 'neutral' information was often perceived as being very negative.

ACTUAL FINDINGS

Is possible to estimate people's understanding more precisely (in terms of H, R and T) which can help healthcare practitioners to modulate the way they convey information.

LIMITATIONS

The participants in the study were healthy volunteers and the context was simulated.

Order-Constrained Estimation of Nominal Response Model Parameters to Assess the Empirical Order of Categories

Bock's nominal response model (NRM) is sometimes used to identify the empirical order of response categories in polytomous items but its application tags many items as having disordered categories. Disorderly estimated categories may not reflect a true characteristic of the items but, rather, a numerically best-fitting solution possibly equivalent to other solutions with orderly estimated categories. To investigate this possibility, an order-constrained variant of the NRM was developed that enforces the preassumed order of categories on parameter estimates, for a comparison of its outcomes with those of the original unconstrained NRM. For items with ordered categories, order-constrained and unconstrained solutions should account for the data equally well even if the latter solution estimated disordered categories for some items; for items with truly disordered categories, the unconstrained solution should outperform the order-constrained solution. Criteria for this comparative analysis are defined and their utility is tested in several simulation studies with items of diverse characteristics, including ordered and disordered categories. The results demonstrate that a comparison of order-constrained and unconstrained calibrations on such criteria provides the evidence needed to determine whether category disorder estimated on some items by the original unconstrained form of the NRM is authentic or spurious. Applications of this method to assess category order in existing data sets are presented and practical implications are discussed.

Psychometric approach of the revised illness perception questionnaire for oral health (IPQ-R-OH) in patients with periodontal disease

BACKGROUND

The purpose of this study was to evaluate the psychometric properties of the validated Spanish version of the Illness Perception Questionnaire Revised for Oral Health (IPQ-R-OH) in patients with periodontal disease.

METHODS

We used the IPQ-R-OH, a 36-item self-report scale. This study was carried out using data from 517 patients with periodontal disease attending the dental clinic at the Universidad Cooperativa de Colombia, Pasto, Colombia. A three-parameter logistic model (3PL) for polytomous response was calculated to evaluate a model of individuals' responses. The McDonald's Omega (Ω ≥ 0.60) coefficient and composite reliability were used to determine the internal consistency. Confirmatory factor analysis (CFA) was conducted to examine the fit of the hypothesized seven-factor model, and the configural invariance was tested to estimate the structure in each sex group.

RESULTS

The slope, location, and guessing parameters determined reasonable accurate items according to item response theory analysis. The internal consistency coefficients of each factor ranged from 0.62 to 0.93 (McDonald's Omega) and 0.66 to 0.87 (composite reliability). Confirmatory factor analysis indicated a seven-factor model (χ² _S-B  = 2572.165; χ² _S-B /(573) = 4.489, P < 0.01; non-normed fit index = 0.950; CFI = 0.950; root means square error of approximation = 0.055 (90% confidence interval [0.052 - 0.059]); standardized root mean residual = 0.080 and Akaike information criteria = 1426.165. The seven factors loaded similarly to the original IPQ-R scale. Multigroup CFA analysis results supported factor invariance across the sex groups.

CONCLUSION

These findings suggest that the IPQ-R-OH has adequate reliability and construct factorial validity; therefore, it could be a valuable instrument in screening illness perceptions in patients with periodontal disease.

Psychometric evaluation of the Chinese version of the revised illness perception questionnaire for breast cancer-related lymphedema

The aim of this study was to modify and test the Chinese version of the Revised Illness Perception Questionnaire to measure the illness perception of breast cancer-related lymphedema among breast cancer survivors. Before the investigation, identity and causal subscales were modified and the wording of the remaining scales was also adjusted. The psychometric properties of this instrument was evaluated using the technique of explore and confirmatory factor analysis. Data from 203 breast cancer survivors was entered into factor analysis. Five causal factors were extracted after removing one item, accounting for 68.02% of the variance in total. An acceptable fit with the data for the proposed seven-factor model was obtained after eliminating three items and resetting seven error covariances. The Cronbach's α values and composite reliability coefficients were acceptable. This measurement is reliable and valid for measuring illness perceptions of breast cancer-related lymphedema in Chinese breast cancer survivors. It could be helpful for further studies that examine the effect of illness perceptions on health-related behaviours, such as lymphedema risk-reduction behaviours in the Chinese cultural context.

An Integrated Approach to Bias in a Longitudinal Survey in the United Kingdom: Assessing Construct, Method, and Item Bias in the General Health Questionnaire (GHQ-12)

Construct, method, and item bias are three levels of measurement bias (i.e., internal bias) essential for valid group comparisons. While many studies often focus on only one level of bias, an integrated perspective on bias is still missing, especially in longitudinal designs. The aim of this study is to address bias in an integrated manner, using four waves of data in the U.K. Longitudinal Household Panel Survey. Responses to the General Health Questionnaire (GHQ-12) from natives and two generations of immigrants were used to analyze the three levels of bias. While the basic structure of the GHQ-12 was stable across groups and time, item and method bias decreased with repeated administrations. Results were confirmed with a sensitivity test. The integrated results allowed for a distinction between temporal sources of bias that became smaller over time and sources affecting valid comparisons persistently. We discuss the implications for mental health assessment.

Illness Perceptions, Medication Beliefs, and Adherence to Antiretrovirals and Medications for Comorbidities in Adults With HIV Infection and Hypertension or Chronic Kidney Disease

BACKGROUND

Mortality in patients with HIV infection is increasingly due to comorbid medical conditions. Research on how adherence to medications for comorbidities relates to antiretroviral (ARV) medication adherence and how interrelations between illness perceptions and medication beliefs about HIV and comorbidities affect medication adherence is needed to inform adherence interventions.

METHODS

HIV-infected adults with hypertension (HTN) (n = 151) or chronic kidney disease (CKD; n = 41) were recruited from ambulatory practices at an academic medical center. Illness perceptions and medication beliefs about HIV and HTN or CKD were assessed and adherence to one ARV medication and one medication for either HTN or CKD was electronically monitored for 10 weeks.

RESULTS

Rates of taking, dosing, and timing adherence to ARV medication did not differ from adherence to medication for HTN or CKD, with the exception that patients were more adherent to the timing of their ARV (78%) than to the timing of their antihypertensive (68%; P = 0.01). Patients viewed HIV as better understood, more chronic, having more negative consequences, and eliciting more emotions, compared with HTN. Patients viewed ARVs as more necessary than medication for HTN or CKD. Having a realistic view of the efficacy of ARVs (r = -0.20; P < 0.05) and a high level of perceived HIV understanding (r = 0.21; P < 0.05) correlated with better ARV adherence.

CONCLUSIONS

Patients with HIV showed similar rates of adherence to ARVs as to medications for comorbidities, despite perceiving HIV as more threatening and ARVs as more important. This can be used in adapting existing interventions for ARV adherence to encompass adherence to medications for comorbid conditions.

Psychometric Properties of the Revised Illness Perception Questionnaire for Oral Health

Aims: The aim of this study was to test the hypothesis that, for patients with dental caries, the Spanish version of the Revised Illness Perception Questionnaire for Oral Health (IPQ-R-OH) has 7 dimensions, including personal and treatment control, timeline-acute/chronic and timeline-cyclical, illness coherence, consequences, and emotional representations. Methods: A Spanish adaptation of the IPQ-R, with a self-reported 38-item scale, was developed. Exploratory and confirmatory factor analyses were conducted using data from 520 patients with dental caries attending the Dental Clinic at Universidad Cooperativa de Colombia, Pasto, Colombia. Results: Exploratory factor analysis revealed 7 dimensions with 36 items (2 items were removed because of poor factor loadings or discriminant ability). The internal consistency coefficients of each factor ranged from 0.72 to 0.91, and all item loadings were >0.52. Confirmatory factor analysis indicated that a 7-factor model with 36 items had superior fit compared to the 38-item original model: χ2 = 1,784.291 (df = 573, p < 0.001); nonnormal fit index = 0.941; comparative fit index = 0.946; root mean square error of approximation = 0.062 (90% CI = 0.057-0.066); standardized root mean square residual = 0.072; and Akaike information criterion = 638.291. Control (integrated by items from personal control, treatment control, and timeline-acute factors) and hopelessness (PC15 and PC17) were the 2 reconfigured factors that were identified. Conclusions: These findings suggest that the modified 36-item model has satisfactory reliability and construct factorial validity; therefore, it could be a valuable instrument in the screening of illness perceptions in oral health.

An Analysis of (Dis)Ordered Categories, Thresholds, and Crossings in Difference and Divide-by-Total IRT Models for Ordered Responses

Threshold parameters have distinct referents across models for ordered responses. In difference models, thresholds are trait levels at which responding beyond category k is as likely as responding at or below it; in divide-by-total models, thresholds are trait levels at which responding in category k is as likely as responding in category k - 1. Thus, thresholds in divide-by-total models (but not in difference models) are the crossings of the option response functions for consecutive categories. Thresholds in difference models are always ordered but they may inconsequentially yield ordered or disordered crossings. In contrast, assimilation of thresholds and crossings in divide-by-total models questions category order when crossings are disordered. We analyze these aspects of difference and divide-by-total models, their relation to the order of response categories, and the consequences of collapsing categories to instate ordered crossings under divide-by-total models. We also show that item parameters in models for ordered responses can never contradict the pre-assumed order of categories and that the empirical order can only be established using a polytomous model that does not assume ordered categories, although this often gives rise to spurious outcomes. Practical implications for scale development are discussed.

Factors associated with psychological distress in women with breast cancer-related lymphoedema

BACKGROUND

Previous research has shown that lymphoedema impacts negatively on an individual, including psychological distress and body image disturbance, particularly for younger women. This study identified psychological factors associated with distress in women with breast cancer-related lymphoedema and determined whether age moderated the specific relationship between body image disturbance and distress.

METHODS

Australian women (n = 166) diagnosed with breast cancer-related lymphoedema were recruited through a community-based breast cancer organisation and lymphoedema treatment clinics. Participants completed an online survey assessing lymphoedema-related cognitions (personal control, perceived treatment effectiveness, and consequences of lymphoedema), perceived ability to self-regulate lymphoedema-related negative affect, body image disturbance, psychological distress (depression, anxiety and stress), and demographic/medical information.

RESULTS

Beliefs about the consequences, perceived effectiveness of treatment and controllability of lymphoedema, perceived ability to self-regulate negative affect, body image disturbance, and number of lymphoedema symptoms were correlated with depression, anxiety, and stress scores. Multivariate regression analyses indicated that body image disturbance was significantly associated with depression, anxiety, and stress, and perceived treatment effectiveness was associated with stress. Age was a significant moderator of the relationship between body image disturbance and depression and anxiety, with older women with greater body image disturbance more distressed.

CONCLUSIONS

Health professionals need to be aware that women diagnosed with lymphoedema are at risk of experiencing psychological distress, particularly arising from body image disturbance and beliefs that treatment cannot control lymphoedema. Furthermore, older women may be at an increased risk of anxiety and depression arising from body image disturbance. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Traditional and Rasch psychometric analyses of the Quality of Life in Adult Cancer Survivors (QLACS) questionnaire in shorter-term cancer survivors 15 months post-diagnosis

OBJECTIVE

The aim of this paper is to provide new insights into the psychometrics of the Quality of Life in Adult Cancer Survivors (QLACS) questionnaire, originally developed for longer-term survivors 5+years post-diagnosis. Specifically, to examine the classic psychometric properties of QLACS in a sample of shorter-term survivors, and to undertake Rasch analysis to explore the extent to which the Generic and Cancer-Specific summary scales (and separately-analysed Benefits of cancer domain) are unidimensional, with linear measurement properties and no differential item functioning (DIF).

METHODS

Patients with potentially curable breast, colorectal or prostate cancer completed QLACS 15 months post-diagnosis (N=407). Score distributions, floor and ceiling effects, internal reliability, and feasibility (completion time and missing data) were examined. Rasch analysis included examination of item fit, DIF and unidimensionality.

RESULTS

The QLACS domains and summary scales had very similar score distributions and classic psychometric properties (no ceiling effects, majority no floor effects, acceptable reliability) to those found in development work with longer-term survivors. Median completion time was 10 min and total missing data 2.3%. The Generic summary scale contained several misfitting items and exhibited multidimensionality. The Cancer-Specific summary scale and Benefits domain showed fit to the Rasch model and demonstrated unidimensionality and no DIF, with just one or no item modifications respectively.

CONCLUSION

QLACS demonstrates similarly good classic psychometric properties among shorter-term as among longer-term survivors, and has good feasibility. The Cancer-Specific summary scale and Benefits domain showed an impressive degree of fit to the Rasch model, although the validity of computing the Generic summary score was not supported.