Loading...
26 results
Search Results
Now showing 1 - 10 of 26
- Modelling health state preference data using fixed and random effects modelsPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Pereira, Luis NobreThe use of preference-based measures of health in the measurement of Health Related Quality of Life has become widely used in health economics. Hence, the development of preference-based measures of health has been a major concern for researchers throughout the world. This study aims to model health state preference data using a new preference-based measure of health (the SF- 6D) and to suggest alternative models for predicting health state utilities using fixed and random effects models. It also seeks to investigate the problems found in the SF-6D and to suggest eventual changes to it.
- Exploring the consistency of the SF-6DPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Pereira, Luis; Rowen, Donna; Brazier, John E.Objective: The six dimensional health state short form (SF-6D) was designed to be derived from the short-form 36 health survey (SF-36). The purpose of this research was to compare the SF-6D index values generated from the SF 36 (SF-6D(SF-36)) with those obtained from the SF-6D administered as an independent instrument (SF-6D(Ind)). The goal was to assess the consistency of respondents answers to these two methods of deriving the SF-6D. Methods: Data were obtained from a sample of the Portuguese population (n = 414). Agreement between the instruments was assessed on the basis of a descriptive system and their indexes. The analysis of the descriptive system was performed by using a global consistency index and an identically classified index. Agreement was also explored by using correlation coefficients. Parametric tests were used to identify differences between the indexes. Regression models were estimated to understand the relationship between them. Results: The SF-6D(Ind) generates higher values than does the SF-6D(SF-36), There were significant differences between the indexes across sociodemographic groups. There was a significant ceiling effect in the SF-6D(Ind) a but not in the SF-6D(SF-36). The correlation between the indexes was high but less than what was anticipated. The global consistency index identified the dimensions with larger differences. Considerable differences were found in two dimensions, possibly as a result of different item contexts. Further research is needed to fully understand the role of the different layouts and the length of the questionnaires in the respondents' answers. Conclusions: The results show that as the SF-6D was designed to derive utilities from the SF-36 it should be used in this way and not as an independent instrument.
- A hybrid modelling approach for eliciting health state preferences: the Portuguese EQ-5D-5L value setPublication . Ferreira, Pedro L.; Antunes, Patricia; Ferreira, Lara; Pereira, LN; Ramos-Goni, Juan M.Background The EQ-5D is a generic preference-based quality of life measure considered useful for supporting clinical and policy decisions by providing utility values that can easily be converted into quality-adjusted life years to be integrated in cost-utility economic evaluations. Although the three-level classification system of the EuroQol questionnaire (EQ-5D-3L) is still the most popular preference-based instrument used worldwide, several studies reported a ceiling effect on this version, especially in healthy and/or young individuals. In 2009, the EuroQol Group introduced a five-level EQ-5D, which expands the descriptive system from three to five levels within the same five dimensions. For this version to be used in health economic evaluation, societal values need to be assigned to the 3125 health states generated by this instrument. Objectives The aims of this study were to elicit the EQ-5D-5L health state preferences from the general Portuguese population and to derive the Portuguese value set for the EQ-5D-5L. Methods A representative sample of the Portuguese general population aged above 18 years was stratified by age and gender (n = 1451). Between October 2015 and July 2016, 28 interviewers carried out a series of 1-h-long computer-assisted personal interviews following the EuroQol Valuation Technology protocol. Each interview included the valuation of ten health states using the composite time trade-off (cTTO) and seven pairs of discrete choice experiments (DCEs). A standardized tool for quality control was used to assess the quality of the data as well as direct supervision and cross-examination of 10% of the global sample size. Data from both cTTO and DCE valuation tasks were modelled using a censored heteroskedastic hybrid model. Results Interviewers complied with the quality control protocol in providing high-quality valuation data. The hybrid econometric model had consistent and significant parameters. The derived societal values for the Portuguese population ranged from - 0.603 to 1. Conclusion This study provided the Portuguese value set for the EQ-5D-5L on the basis of a hybrid econometric model using cTTO and DCE data. These results represent the preferences of the Portuguese population and are recommended to inform health decision-making in Portugal.
- Does Aortic Valve replacement surgery improve patients' Quality of Life?Publication . Coelho, Pedro; Ferreira, Lara; Vital, Clara; Fragata, JoséIntroduction: Aortic valve replacement surgery is done to increase patients' life expectancy and improve their health-related quality of life. Several published studies have found improvement in health-related quality of life after this procedure, but none have involved patients in Portugal. This study sought to evaluate patients' health-related quality of life after the implantation of aortic prostheses and compare these values with preoperative health-related quality of life and the general Portuguese population's health-related quality of life. Material and Methods: A retrospective study was done with elective patients who underwent implantation of an aortic prosthesis between August 2011 and April 2016. Health-related quality of life was evaluated using the Short Form 36 Health Survey and Short Form 6 Health Survey questionnaires in the preoperative period and 3, 6 and 12 months post-surgery. Descriptive and inferential analyses were conducted to process the data and compare preoperative health-related quality of life with postoperative values and the Portuguese population's norms. Results: The sample included 506 patients with an average age of 70.6 years. The majority are male (53.6%). The postoperative results show a statistically significant improvement compared to preoperative health-related quality of life in all eight dimensions of the Short Form 36 Health Survey. When contrasted with the general Portuguese population, patients' health-related quality of life is lower in the preoperative period, improving postoperatively and reaching higher than average health-related quality of life levels in some subgroups of patients and in various dimensions. An analysis of the Short Form 6 Health Survey results revealed that the patients undergoing this surgery have a higher level of preoperative problems compared with the general population, but these patients' values approach those of the general population by the end of one year post-surgery. Discussion: This is the first study in Portugal that compares health-related quality of life using a validated scale, before and after the aortic prosthesis implantation surgery. The results demonstrate a significant improvement in all dimensions, which is not consistently observed in other published studies. Conclusion: The results confirm that the implantation of aortic prostheses improves patients' health-related quality of life, over time bringing it close to the general population's levels.
- O sistema português de valores do SF-6DPublication . Ferreira, Pedro L.; Ferreira, Lara Noronha; Pereira, Luis NobreIntrodução: Nos últimos tempos tem-se assistido ao desenvolvimento de estudos em alguns países, de forma a obter funções de valoração relativas aos instrumentos de medição de preferências mais utilizados. Na verdade, a evidência sugere que as valorações dos estados de saúde podem diferir de país para país. O objectivo deste estudo foi a determinação de um sistema de valores subjacente ao SF-6D para Portugal. Metodologia: Uma amostra de 55 estados de saúde definidos pelo SF-6D foi valorizada por uma amostra aleatória estratificada da população em geral, utilizando o standard gamble (SG). A pesquisa foi conduzida por entrevistas pessoais, tendo os respondentes valorizado seis estados de saúde, acrescidos do pior estado de saúde definido pelo SF-6D ou da morte imediata. Estimaram-se vários modelos com o objectivo de prever as valorações dos estados de saúde. Numa primeira fase, foram estimados modelos lineares, tanto ao nível individual, como agregado, assim como modelos com efeitos fixos, com efeitos principais e de interacção e com a constante forçada à unidade. Numa segunda fase, foram ainda testados, pelo método dos mínimos quadrados generalizados, modelos com efeitos aleatórios (MEA). Foram também estimados MEA com a constante forçada à unidade pelas equações de estimação generalizadas (EEG). Consideraram-se especificações alternativas, como forma de tomar em consideração o enviesamento das valorações dos estados de saúde. Os modelos foram analisados em termos dos seus coeficientes, ajustamento e capacidade para prever os valores dos estados de saúde captados pelo SG. Resultados: Os MEA e os modelos EEG produziram coeficientes significativos, que se verificou serem robustos nas especificações dos modelos. A utilização de uma bateria de medidas de bondade do ajustamento levou à conclusão que o modelo EEG com efeitos principais era o melhor modelo estimado. Conclusão: Esta investigação demonstra que é possível obter sistemas de pesos para a medição da qualidade de vida relacionada com a saúde. O melhor modelo obtido parece prever adequadamente os valores dos estados de saúde da população portuguesa. No entanto, existem algumas incoerências que devem ser investigadas.
- Quality of life in asthma patientsPublication . Ferreira, Lara; Brito, Ulisses; Ferreira, Pedro LopesIn this paper we present a study whose main aim is the measurement of the Health Related Quality of Life (HRQoL) of patients with asthma and the presentation of a first draft of normative values as measured by the SF-6D for asthma patients. In addition, we investigate how far non-disease-specific HRQoL measures can distinguish groups in terms of socio-demographic characteristics. The Portuguese versions of the EQ-5D, SF-6D, AQLQ(S) and ACQ were administered using personal interviews to a representative sample of the Portuguese population with asthma. Most of the individuals did not report significant problems in the dimensions used, with the exception of the physical functioning, where individuals reported moderate limitations. The mean utility value was 0.86. Male gender, young, single, individuals with high educational attainment level, employed, individuals with high income and those residing in urban areas reported higher utility levels. As expected, those who were in a severe stadium of the disease reported lower mean utility levels than those who were in a less severe stadium of the disease. Normative values for the SF-6D were computed for patients with asthma by gender, age, marital status, educational attainment level, employment status, area of residence and average monthly net income. The preference-based measures used in this study distinguish patient groups with asthma in terms of socio-demographic groups. The normative values can be used in economic evaluation and clinical studies as they incorporate patients' preferences and translate the value attributed to patients' health state.
- Avaliação Económica e Social dos Concelhos do AlgarvePublication . Pereira, Luis Nobre; Ferreira, Lara Noronha; Jesús, MargaridaEste estudo tem como objectivo principal realizar uma avaliação económica e social dos concelhos do Algarve através de Índices de Desenvolvimento Concelhio. A realização de análises exploratórias multivariadas suportou a construção desses Índices de Desenvolvimento. As assimetrias existentes entre os concelhos puderam ser identificadas através da formação de grupos homogéneos de concelhos.
- Comparing the performance of the EQ-5D-3L and the EQ-5D-5L in young Portuguese adultsPublication . Ferreira, Lara Noronha; Ferreira, Pedro L.; Perdigão, Filipa; Pereira, LuisBackground Some studies have reported a ceiling effect in EQ-5D-3L, especially in healthy and/or young individuals. Recently, two further levels have been included in its measurement model (EQ-5D-5L). The purposes of this study were (1) to assess the properties of the EQ-5D-5L in comparison with the standard EQ-5D-3L in a sample of young adults, (2) to foreground the importance of collecting qualitative data to confirm, validate or refine the EQ-5D questionnaire items and (3) to raise questions pertaining to the wording in these questionnaire items. Methods The data used came from a sample of respondents aged 30 or under (n = 624). They completed both versions of the EQ-5D, which were compared in terms of feasibility, level of inconsistency and ceiling effect. Agreement between the instruments was assessed using correlation coefficients and Bland-Altman plots. Known-groups validity of the EQ-5D-5L was also assessed using non-parametric tests. The discriminative properties were compared using receiver operating characteristic curves. Finally, four interviews were conducted for retrospective reports to elicit respondents’ understanding and perceptions of the format, instructions, items, and responses. Results Quantitative results show a ceiling effect reduction of 25.3 % and a high level agreement between both indices. Known-groups validity was confirmed for the EQ-5D-5L. Explorative interviews indicated ambiguity and low degree of certainty in regards to conceptualizing differences between levels moderate-slight across three dimensions. Conclusions The EQ-5D-5L performed better than the EQ-5D-3L. However, the explorative interviews demonstrated several limitations in the EQ-5D questionnaire wording and high context-dependent answers point to lack of illnesses’ experience amongst young adults.
- Assessing Health-Related Quality of life in patients with Psoriasis compared with the portuguese populationPublication . Ferreira, Lara; Oliveira Martins, S.; Moital, I.; Ferreira, P.; Varela, P.; Oliveira, H.; Laires, P. A.; Cabrita, J.To assess the health-related quality of life (HRQoL) in patients with psoriasis (PsO) and to compare with the Portuguese general population. It also aims to explore the associations between HRQoL and sociodemographic variables.
- Contribution for the validation of the portuguese version of EQ-5DPublication . Ferreira, Pedro Lopes; Ferreira, Lara Noronha; Pereira, Luis NobreIntroduction: The EQ-5D allows the achievement of two essential components of any measure of health-related quality of life to be used in cost-utility economic evaluations: (i) a profile describing the health status in terms of domains or dimensions; and (ii) a numeric value associated with the health status described. Aim: The Portuguese version of the EQ-5D questionnaire was completed in 1998, based on guidelines set by the EuroQol Group, including translation and back translation procedures. Despite its wide use in Portugal, until now it had not yet been published studies that initially led to the Portuguese version and the guarantee of acceptability, reliability and validity. The purpose of this article is to document these first values relating to the Portuguese version of the EQ-5D. Material and Methods: We used three different samples: a first one with 1,500 individuals representative of the Portuguese population; a second with 140 individuals just intended for the reliability test; and a third sample with 643 individual patients with cataracts, asthma, chronic obstructive pulmonary disease, or rheumatoid arthritis. Results: The acceptability was assessed by the number of missing responses. It was also found a marked ceiling effect, with a large part of the sample not reporting any problems in the dimensions of the EQ-5D. Discussion: The construct validity was tested by examining the degree to which low values of EQ-5D were positively associated with increasing age, being female, and the sick, as well as the values of dimensions of the SF-36v2 scale. Convergent validity was based on correlations between EQ-5D values and other specific measures. The EQ-5D showed moderate to high correlations with other disease-specific measures of health status and health related quality of life. Conclusion: We can state that the Portuguese version of the EQ-5D has a good accessibility, reliability and validity in measuring health.
- «
- 1 (current)
- 2
- 3
- »