Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 7 de 7
Filtrar
1.
Qual Life Res ; 33(5): 1241-1256, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38427288

RESUMEN

PURPOSE: Statistical power for response shift detection with structural equation modeling (SEM) is currently underreported. The present paper addresses this issue by providing worked-out examples and syntaxes of power calculations relevant for the statistical tests associated with the SEM approach for response shift detection. METHODS: Power calculations and related sample-size requirements are illustrated for two modelling goals: (1) to detect misspecification in the measurement model, and (2) to detect response shift. Power analyses for hypotheses regarding (exact) overall model fit and the presence of response shift are demonstrated in a step-by-step manner. The freely available and user-friendly R-package lavaan and shiny-app 'power4SEM' are used for the calculations. RESULTS: Using the SF-36 as an example, we illustrate the specification of null-hypothesis (H0) and alternative hypothesis (H1) models to calculate chi-square based power for the test on overall model fit, the omnibus test on response shift, and the specific test on response shift. For example, we show that a sample size of 506 is needed to reject an incorrectly specified measurement model, when the actual model has two-medium sized cross loadings. We also illustrate power calculation based on the RMSEA index for approximate fit, where H0 and H1 are defined in terms of RMSEA-values. CONCLUSION: By providing accessible resources to perform power analyses and emphasizing the different power analyses associated with different modeling goals, we hope to facilitate the uptake of power analyses for response shift detection with SEM and thereby enhance the stringency of response shift research.


Asunto(s)
Análisis de Clases Latentes , Humanos , Modelos Estadísticos , Tamaño de la Muestra , Calidad de Vida
2.
Qual Life Res ; 30(5): 1293-1304, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33550541

RESUMEN

BACKGROUND: Patient-reported outcomes (PROs) are of increasing importance for health-care evaluations. However, the interpretation of change in PROs may be obfuscated due to changes in the meaning of the self-evaluation, i.e., response shift. Structural equation modeling (SEM) is the most widely used statistical approach for the investigation of response shift. Yet, non-technical descriptions of SEM for response shift investigation are lacking. Moreover, application of SEM is not straightforward and requires sequential decision-making practices that have not received much attention in the literature. AIMS: To stimulate appropriate applications and interpretations of SEM for the investigation of response shift, the current paper aims to (1) provide an accessible description of the SEM operationalizations of change that are relevant for response shift investigation; (2) discuss practical considerations in applying SEM; and (3) provide guidelines and recommendations for researchers who want to use SEM for the investigation and interpretation of change and response shift in PROs. CONCLUSION: Appropriate applications and interpretations of SEM for the detection of response shift will help to improve our understanding of response shift phenomena and thus change in PROs. Better understanding of patients' perceived health trajectories will ultimately help to adopt more effective treatments and thus enhance patients' wellbeing.


Asunto(s)
Medición de Resultados Informados por el Paciente , Calidad de Vida/psicología , Humanos , Proyectos de Investigación
3.
Ann Surg Oncol ; 26(13): 4765-4772, 2019 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-31620943

RESUMEN

BACKGROUND: The course of health-related quality of life (HRQOL) during and after completion of neoadjuvant chemoradiotherapy (nCRT) for esophageal or junctional carcinoma is unknown. METHODS: This study was a multicenter prospective cohort investigation. Patients with esophageal or cancer to be treated with nCRT plus esophagectomy were eligible for inclusion in the study. The HRQOL of the patients was measured with European Organization for Research and Treatment of Cancer QLQ-C30, QLQ-OG25, and QLQ-CIPN20 questionnaires before and during nCRT, then 2, 4, 6, 8, 10, 12, 14, and 16 weeks after nCRT and before surgery. Predefined end points were based on the hypothesized impact of nCRT. The primary end points were physical functioning, odynophagia, and sensory symptoms. The secondary end points were global quality of life, fatigue, weight loss, and motor symptoms. Mixed modeling analysis was used to evaluate changes over time. RESULTS: Of 106 eligible patients, 96 (91%) were included in the study. The rate of questionnaires returned ranged from 94% to 99% until week 12, then dropped to 78% in week 16 after nCRT. A negative impact of nCRT on all HRQOL end points was observed during the last cycle of nCRT (all p < 0.001) and 2 weeks after nCRT (all p < 0.001). Physical functioning, odynophagia, and sensory symptoms were restored to pretreatment levels respectively 8, 4, and 6 weeks after nCRT. The secondary end points were restored to baseline levels 4-6 weeks after nCRT. Odynophagia, fatigue, and weight loss improved after nCRT compared with baseline levels at respectively 6 (p < 0.001), 16 (p = 0.001), and 12 weeks (p < 0.001). CONCLUSION: After completion of nCRT for esophageal cancer, HRQOL decreases significantly, but all HRQOL end points are restored to baseline levels within 8 weeks. Odynophagia, fatigue, and weight loss improved 6-16 weeks after nCRT compared with baseline levels.


Asunto(s)
Quimioradioterapia Adyuvante/mortalidad , Neoplasias Esofágicas/terapia , Carcinoma de Células Escamosas de Esófago/terapia , Unión Esofagogástrica/patología , Terapia Neoadyuvante/mortalidad , Calidad de Vida , Anciano , Neoplasias Esofágicas/patología , Carcinoma de Células Escamosas de Esófago/patología , Femenino , Estudios de Seguimiento , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Estudios Prospectivos , Tasa de Supervivencia
4.
Multivariate Behav Res ; 54(4): 457-474, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30856354

RESUMEN

Structural equation modeling is a common technique to assess change in longitudinal designs. However, these models can become of unmanageable size with many measurement occasions. One solution is the imposition of Kronecker product restrictions to model the multivariate longitudinal structure of the data. The resulting longitudinal three-mode models (L3MMs) are very parsimonious and have attractive interpretation. This paper provides an instructive description of L3MMs. The models are applied to health-related quality of life (HRQL) data obtained from 682 patients with painful bone metastasis, with eight measurements at 13 occasions; before and every week after treatment with radiotherapy. We explain (1) how the imposition of Kronecker product restrictions can be used to model the multivariate longitudinal structure of the data, (2) how to interpret the Kronecker product restrictions and the resulting L3MM parameters, and (3) how to test substantive hypotheses in L3MMs. In addition, we discuss the challenges for the evaluation of (differences in) fit of these complex and parsimonious models. The L3MM restrictions lead to parsimonious models and provide insight in the change patterns of relationships between variables in addition to the general patterns of change. The L3MM thus provides a convenient model for multivariate longitudinal data, as it not only facilitates the analysis of complex longitudinal data but also the substantive interpretation of the dynamics of change.


Asunto(s)
Modelos Estadísticos , Análisis Multivariante , Neoplasias Óseas , Humanos , Estudios Longitudinales , Calidad de Vida
5.
Ann Oncol ; 29(2): 445-451, 2018 02 01.
Artículo en Inglés | MEDLINE | ID: mdl-29126244

RESUMEN

Background: Neoadjuvant chemoradiotherapy (nCRT) plus surgery is a standard of care for patients with esophageal or junctional cancer, but the long-term impact of nCRT on health-related quality of life (HRQOL) is unknown. The purpose of this study is to compare very long-term HRQOL in long-term survivors of esophageal cancer who received nCRT plus surgery or surgery alone. Patients and methods: Patients were randomly assigned to receive nCRT (carboplatin/paclitaxel with 41.4-Gy radiotherapy) plus surgery or surgery alone. HRQOL was measured using EORTC-QLQ-C30, EORTC-QLQ-OES24 and K-BILD questionnaires after a minimum follow-up of 6 years. To allow for examination over time, EORTC-QLQ-C30 and QLQ-OES24 questionnaire scores were compared with pretreatment and 12 months postoperative questionnaire scores. Physical functioning (QLQ-C30), eating problems (QLQ-OES24) and respiratory problems (K-BILD) were predefined primary end points. Predefined secondary end points were global quality of life and fatigue (both QLQ-C30). Results: After a median follow-up of 105 months, 123/368 included patients (33%) were still alive (70 nCRT plus surgery, 53 surgery alone). No statistically significant or clinically relevant differential effects in HRQOL end points were found between both groups. Compared with 1-year postoperative levels, eating problems, physical functioning, global quality of life and fatigue remained at the same level in both groups. Compared with pretreatment levels, eating problems had improved (Cohen's d -0.37, P = 0.011) during long-term follow-up, whereas physical functioning and fatigue were not restored to pretreatment levels in both groups (Cohen's d -0.56 and 0.51, respectively, both P < 0.001). Conclusions: Although physical functioning and fatigue remain reduced after long-term follow-up, no adverse impact of nCRT is apparent on long-term HRQOL compared with patients who were treated with surgery alone. In addition to the earlier reported improvement in survival and the absence of impact on short-term HRQOL, these results support the view that nCRT according to CROSS can be considered as a standard of care. Trial registration number: Netherlands Trial Register NTR487.


Asunto(s)
Quimioradioterapia Adyuvante/efectos adversos , Neoplasias Esofágicas/terapia , Terapia Neoadyuvante/efectos adversos , Calidad de Vida , Adenocarcinoma/terapia , Adulto , Anciano , Protocolos de Quimioterapia Combinada Antineoplásica/administración & dosificación , Supervivientes de Cáncer , Carboplatino/administración & dosificación , Carcinoma de Células Escamosas/terapia , Quimioradioterapia Adyuvante/métodos , Procedimientos Quirúrgicos del Sistema Digestivo , Unión Esofagogástrica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Terapia Neoadyuvante/métodos , Paclitaxel/administración & dosificación , Encuestas y Cuestionarios
6.
Qual Life Res ; 28(10): 2637-2639, 2019 10.
Artículo en Inglés | MEDLINE | ID: mdl-31515747

Asunto(s)
Calidad de Vida , Humanos
7.
PLoS One ; 16(5): e0252035, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34032803

RESUMEN

BACKGROUND: Effectiveness of psychological treatment is often assessed using patient-reported health evaluations. However, comparison of such scores over time can be hampered due to a change in the meaning of self-evaluations, called 'response shift'. Insight into the occurrence of response shift seems especially relevant in the context of psychological interventions, as they often purposefully intend to change patients' frames of reference. AIMS: The overall aim is to gain insight into the general relevance of response shift for psychological health intervention research. Specifically, the aim is to re-analyse data of published randomized controlled trials (RCTs) investigating the effectiveness of psychological interventions targeting different health aspects, to assess (1) the occurrence of response shift, (2) the impact of response shift on interpretation of treatment effectiveness, and (3) the predictive role of clinical and background variables for detected response shift. METHOD: We re-analysed data from RCTs on guided internet delivered cognitive behavioural treatment (CBT) for insomnia in the general population with and without elevated depressive symptoms, an RCT on meaning-centred group psychotherapy targeting personal meaning for cancer survivors, and an RCT on internet-based CBT treatment for persons with diabetes with elevated depressive symptoms. Structural equation modelling was used to test the three objectives. RESULTS: We found indications of response shift in the intervention groups of all analysed datasets. However, results were mixed, as response shift was also indicated in some of the control groups, albeit to a lesser extent or in opposite direction. Overall, the detected response shifts only marginally impacted trial results. Relations with selected clinical and background variables helped the interpretation of detected effects and their possible mechanisms. CONCLUSION: This study showed that response shift effects can occur as a result of psychological health interventions. Response shift did not influence the overall interpretation of trial results, but provide insight into differential treatment effectiveness for specific symptoms and/or domains that can be clinically meaningful.


Asunto(s)
Terapia Cognitivo-Conductual , Depresión/terapia , Diabetes Mellitus/terapia , Trastornos del Inicio y del Mantenimiento del Sueño/terapia , Depresión/epidemiología , Depresión/patología , Diabetes Mellitus/epidemiología , Diabetes Mellitus/patología , Femenino , Humanos , Masculino , Salud Mental/normas , Persona de Mediana Edad , Psicoterapia/tendencias , Ensayos Clínicos Controlados Aleatorios como Asunto , Sueño/fisiología , Trastornos del Inicio y del Mantenimiento del Sueño/epidemiología , Trastornos del Inicio y del Mantenimiento del Sueño/patología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA