Cross-Language Differential Item Functioning of the Job Content Questionnaire Among European Countries: The JACE Study

Background  Little is known about cross-language measurement equivalence of the job content questionnaire (JCQ) Purpose  The purposes of this study were to assess the extent of cross-language differential item functioning (DIF) of the 27 JCQ items in six languages (French, Dutch, Belgian-French, Belgian-Dutch (Flemish), Italian, and Swedish) from six European research centers and to test whether its effects on the scale-level mean comparisons among the centers were substantial or not. Method  A partial gamma coefficient method was used for statistical DIF analyses where the Flemish JCQ was the reference for other language versions. Additionally, equivalence between the Flemish and Dutch translations was subjected to a judgmental review. Results  On average, 36% to 39% of the total tested items appeared to be cross-language DIF items in the statistical analyses. The judgmental review indicated that half of the DIF items may be associated with translation difference. The impacts of the DIF items on the mean comparisons of the JCQ scales between the centers were non-trivial: underestimated skill discretion (Milan), underestimated decision authority (Leiden), underestimated psychological demands (Milan women), and incomparable coworker support (Gothenburg 95). Conclusion  Cross-language DIF of the JCQ among European countries should be considered in international comparative studies on psychosocial job hazards using JCQ scales.

Evaluation of a computer‐adaptive test for the assessment of depression (D‐CAT) in clinical application

In the past, a German Computerized Adaptive Test, based on Item Response Theory (IRT), was developed for purposes of assessing the construct depression [Computer‐adaptive test for depression (D‐CAT)]. This study aims at testing the feasibility and validity of the real computer‐adaptive application. The D‐CAT, supplied by a bank of 64 items, was administered on personal digital assistants (PDAs) to 423 consecutive patients suffering from psychosomatic and other medical conditions (78 with depression). Items were adaptively administered until a predetermined reliability (r ≥ 0.90) was attained. For validation purposes, the Hospital Anxiety and Depression Scale (HADS), the Centre for Epidemiological Studies Depression (CES‐D) scale, and the Beck Depression Inventory (BDI) were administered. Another sample of 114 patients was evaluated using standardized diagnostic interviews [Composite International Diagnostic Interview (CIDI)]. The D‐CAT was quickly completed (mean 74 seconds), well accepted by the patients and reliable after an average administration of only six items. In 95% of the cases, 10 items or less were needed for a reliable score estimate. Correlations between the D‐CAT and the HADS, CES‐D, and BDI ranged between r = 0.68 and r = 0.77. The D‐CAT distinguished between diagnostic groups as well as established questionnaires do. The D‐CAT proved an efficient, well accepted and reliable tool. Discriminative power was comparable to other depression measures, whereby the CAT is shorter and more precise. Item usage raises questions of balancing the item selection for content in the future. Copyright © 2009 John Wiley & Sons, Ltd.     

Diabetic patients treated with dialysis: complications and quality of life

Aims/hypothesis The aim of this study was to describe the prevalence of complications, health-related quality of life (HRQOL) and the influence of beliefs about control over health in diabetic dialysis patients. Methods Of 53 eligible diabetic patients on chronic dialysis during January 2004 in our clinic, 38 (76%) completed a kidney-specific (Kidney Disease Quality of Life) and a generic (SF-36) questionnaire and were characterised in terms of cardiovascular diseases and diabetic complications. Matched groups of non-diabetic dialysis patients (n = 40) and diabetic patients with a long duration of diabetes and normal kidney function (n = 38) served as controls. Generic HRQOL was compared with matched data from a survey on the Danish general population (n = 2248). Results Micro- and macrovascular complications were significantly more frequent in diabetic dialysis patients than in diabetic patients without renal disease. Self-rated physical health was significantly worse (p < 0.01) in diabetic dialysis patients (35 ± 9 [mean ± SD]) compared with non-diabetic dialysis patients (41 ± 10), diabetic patients with normal kidney function (45 ± 12) and the matched general population (47 ± 19). The diabetic dialysis patients had similar levels of kidney-specific quality of life and mental health compared with the control groups. Reduced physical health was predicted by the presence of end-stage renal disease, diabetes and short time spent in education. Among the diabetic patients, those who believed more on their own ability to control their diabetes and less on chance reported better mental health and were less likely to be on dialysis. Conclusions/interpretations Diabetic dialysis patients are characterised by a high prevalence of diabetic complications, reduced self-rated physical health but relatively good mental health. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorised users.     

An evaluation of patient-reported outcomes found computerized adaptive testing was efficient in assessing stress perception

ObjectivesThis study aimed to develop and evaluate a first computerized adaptive test (CAT) for the measurement of stress perception (Stress-CAT), in terms of the two dimensions: exposure to stress and stress reaction.Study Design and SettingItem response theory modeling was performed using a two-parameter model (Generalized Partial Credit Model). The evaluation of the Stress-CAT comprised a simulation study and real clinical application. A total of 1,092 psychosomatic patients (N1) were studied. Two hundred simulees (N2) were generated for a simulated response data set. Then the Stress-CAT was given to n = 116 inpatients, (N3) together with established stress questionnaires as validity criteria.ResultsThe final banks included n = 38 stress exposure items and n = 31 stress reaction items. In the first simulation study, CAT scores could be estimated with a high measurement precision (SE < 0.32; ρ > 0.90) using 7.0 ± 2.3 (M ± SD) stress reaction items and 11.6 ± 1.7 stress exposure items. The second simulation study reanalyzed real patients data (N1) and showed an average use of items of 5.6 ± 2.1 for the dimension stress reaction and 10.0 ± 4.9 for the dimension stress exposure. Convergent validity showed significantly high correlations.ConclusionsThe Stress-CAT is short and precise, potentially lowering the response burden of patients in clinical decision making.     

Development of physical and mental health summary scores from the patient-reported outcomes measurement information system (PROMIS) global items

Background  The use of global health items permits an efficient way of gathering general perceptions of health. These items provide useful summary information about health and are predictive of health care utilization and subsequent mortality. Methods  Analyses of 10 self-reported global health items obtained from an internet survey as part of the Patient-Reported Outcome Measurement Information System (PROMIS) project. We derived summary scores from the global health items. We estimated the associations of the summary scores with the EQ-5D index score and the PROMIS physical function, pain, fatigue, emotional distress, and social health domain scores. Results  Exploratory and confirmatory factor analyses supported a two-factor model. Global physical health (GPH; 4 items on overall physical health, physical function, pain, and fatigue) and global mental health (GMH; 4 items on quality of life, mental health, satisfaction with social activities, and emotional problems) scales were created. The scales had internal consistency reliability coefficients of 0.81 and 0.86, respectively. GPH correlated more strongly with the EQ-5D than did GMH (r = 0.76 vs. 0.59). GPH correlated most strongly with pain impact (r = −0.75) whereas GMH correlated most strongly with depressive symptoms (r = −0.71). Conclusions  Two dimensions representing physical and mental health underlie the global health items in PROMIS. These global health scales can be used to efficiently summarize physical and mental health in patient-reported outcome studies.     

Functioning and validity of a Computerized Adaptive Test to measure anxiety (A-CAT)

Background: The aim of this study was to evaluate the Computerized Adaptive Test to measure anxiety (A‐CAT), a patient‐reported outcome questionnaire that uses computerized adaptive testing to measure anxiety. Methods: The A‐CAT builds on an item bank of 50 items that has been built using conventional item analyses and item response theory analyses. The A‐CAT was administered on Personal Digital Assistants to n=357 patients diagnosed and treated at the department of Psychosomatic Medicine and Psychotherapy, Charité Berlin, Germany. For validation purposes, two subgroups of patients (n=110 and 125) answered the A‐CAT along with established anxiety and depression questionnaires. Results: The A‐CAT was fast to complete (on average in 2 min, 38 s) and a precise item response theory based CAT score (reliability>.9) could be estimated after 4–41 items. On average, the CAT displayed 6 items (SD=4.2). Convergent validity of the A‐CAT was supported by correlations to existing tools (Hospital Anxiety and Depression Scale‐A, Beck Anxiety Inventory, Berliner Stimmungs‐Fragebogen A/D, and State Trait Anxiety Inventory: r=.56–.66); discriminant validity between diagnostic groups was higher for the A‐CAT than for other anxiety measures. Conclusions: The German A‐CAT is an efficient, reliable, and valid tool for assessing anxiety in patients suffering from anxiety disorders and other conditions with significant potential for initial assessment and long‐term treatment monitoring. Future research directions are to explore content balancing of the item selection algorithm of the CAT, to norm the tool to a healthy sample, and to develop practical cutoff scores. Depression and Anxiety, 2008. © 2008 Wiley‐Liss, Inc.     

A prospective, randomized multicenter study comparing APD and CAPD treatment.

OBJECTIVE: The goals for maintenance dialysis treatment are to improve patient survival, reduce patient morbidity, and improve patient quality of life. This is the first randomized prospective study comparing automated peritoneal dialysis (APD) and continuous ambulatory peritoneal dialysis (CAPD) treatment with respect to quality of life and clinical outcomes in relation to therapy costs. DESIGN: A prospective, randomized multicenter study. SETTING: Three Danish CAPD units. PATIENTS: Thirty-four adequately dialyzed patients with high or high-average peritoneal transport characteristics were included in the study.Twenty-five patients completed the study. INTERVENTIONS: After randomization, 17 patients were allocated to APD treatment and 17 patients to CAPD treatment for a period of 6 months. Medical and biochemical parameters were evaluated at monthly controls in the CAPD units. Quality-of-life parameters were assessed at baseline and after 6 months by the self-administered short-form SF-36 generic health survey questionnaire supplemented with disease- and treatment-specific questions. Therapy costs were compared by evaluating dialysis-related expenses. MAIN OUTCOME MEASURES: Quality-of-life parameters, dialysis-related complications, dialysis-related expenses. RESULTS: The quality-of-life studies showed that significantly more time for work, family, and social activities was available to patients on APD compared to those on CAPD (p < 0.001). Although the difference was not significant, there was a tendency for less physical and emotional discomfort caused by dialysis fluid in the APD group. Sleep problems, on the other hand, tended to be more marked in the APD group. Any positive effect of APD compared to CAPD on dialysis-related hospital days or complication rates could not be confirmed. With larger patient samples, it is possible, however, that a significant difference might have been achieved. The running costs for APD treatment were US $75 per day and for CAPD treatment US $61 per day. CONCLUSION: If APD treatment can help to keep selected patients vocationally or socially active, paying the extra cost seems reasonable.     

Calibration of an item pool for assessing the burden of headaches: An application of item response theory to the Headache Impact Test (HIT™)

Background: Measurement of headache impact is important in clinical trials, case detection, and the clinical monitoring of patients. Computerized adaptive testing (CAT) of headache impact has potential advantages over traditional fixed-length tests in terms of precision, relevance, real-time quality control and flexibility. Objective: To develop an item pool that can be used for a computerized adaptive test of headache impact. Methods: We analyzed responses to four well-known tests of headache impact from a population-based sample of recent headache sufferers (n = 1016). We used confirmatory factor analysis for categorical data and analyses based on item response theory (IRT). Results: In factor analyses, we found very high correlations between the factors hypothesized by the original test constructers, both within and between the original questionnaires. These results suggest that a single score of headache impact is sufficient. We established a pool of 47 items which fitted the generalized partial credit IRT model. By simulating a computerized adaptive health test we showed that an adaptive test of only five items had a very high concordance with the score based on all items and that different worst-case item selection scenarios did not lead to bias. Conclusion: We have established a headache impact item pool that can be used in CAT of headache impact.