Lara N. Ferreira

How consistent are health utility values

The use of preference-based generic instruments to measure the health-related quality of life of a general population or of individuals suffering from a specific disease has been increasing. However, there are several discrepancies between instruments in terms of utility results. This study compares SF-6D and EQ-5D when administered to patients with cataracts and aims at explaining the differences. Agreement between EQ-5D and SF-6D health state classifications was assessed by correlation coefficients. Simple correspondence analysis was used to assess the agreement among the instrument’s descriptive systems and to investigate similarities between dimensions’ levels. Cluster analysis was used to classify SF-6D and EQ-5D levels into homogeneous groups. There was evidence of floor effects in SF-6D and ceiling effects in EQ-5D. Comparisons of means showed that SF-6D values exceeded EQ-5D values. Agreement between both instruments was high, especially between similar dimensions. However, different valuation methods and scoring algorithms contributed to the main differences found. We suggest that one or both instruments should be revised, in terms of their descriptive systems or their scoring algorithms, in order to overcome the weakness found.

A portuguese value set for the SF-6D

OBJECTIVES The SF-6D is a preference-based measure of health derived from the SF-36 that can be used for cost-effectiveness analysis using cost-per-quality adjusted life-year analysis. This study seeks to estimate a system weight for the SF-6D for Portugal and to compare the results with the UK system weights. METHODS A sample of 55 health states defined by the SF-6D has been valued by a representative random sample of the Portuguese population, stratified by sex and age (n = 140), using the Standard Gamble (SG). Several models are estimated at both the individual and aggregate levels for predicting health-state valuations. Models with main effects, with interaction effects and with the constant forced to unity are presented. Random effects (RE) models are estimated using generalized least squares (GLS) regressions. Generalized estimation equations (GEE) are used to estimate RE models with the constant forced to unity. Estimations at the individual level were performed using 630 health-state valuations. Alternative functional forms are considered to account for the skewed distribution of health-state valuations. RESULTS The models are analyzed in terms of their coefficients, overall fit, and the ability for predicting the SG-values. The RE models estimated using GLS and through GEE produce significant coefficients, which are robust across model specification. However, there are concerns regarding some inconsistent estimates, and so parsimonious consistent models were estimated. There is evidence of under prediction in some states assigned to poor health. The results are consistent with the UK results. CONCLUSION The models estimated provide preference-based quality of life weights for the Portuguese population when health status data have been collected using the SF-36. Although the sample was randomly drowned findings should be treated with caution, given the small sample size, even knowing that they have been estimated at the individual level.

An application of the SF-6D to create heath values in Portuguese working age adults

Objectives: This study describes the health-related quality of life (HRQOL) of the Portuguese working age population and investigates sociodemographic differences. Methods: Subjects randomly selected from the working age population (n=2,459) were assessed using the SF-36v2 and converted into the preference-based SF-6D. Results: The mean SF-6D utility value was 0.70 (range 0.63–0.73). The mean utility value was lower for the lower educational level than for the highest. Women, people living in rural areas and older adults reported lower levels of utility values. Non-parametric tests showed that health utility values were significantly related to employment; unskilled manual workers reported utility values lower than non-manual workers. For different diseases, mean utility values ranged from 0.58 (sexual diseases) to 0.66 (hepatic conditions). Cluster analysis was adopted to classify individuals into three groups according to their answers to the SF-6D dimensions. Multinomial logit regression was used to detect sociodemographic characteristics affecting the probability of following each cluster pattern. This study yielded normative data by age and gender for the SF-6D. Conclusions: The authors conclude that SF-6D is an effective tool for measuring HRQOL in the community so that different population groups can be compared. The preference-based measure used seems to discriminate adequately across sociodemographic differences. These results allow a better understanding of the impact of sociodemographic variables on the burden of illness perception. A previous version of this paper was presented at the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) 8th Annual European Congress held at Florence, Italy in November 2005.

Qualidade de vida em doentes com asma

Resumo Neste artigo e descrito um estudo, cujo objectivo e a medicao da qualidade de vida relacionada com a saude (QdVRS) de doentes com asma e a apresentacao de uma primeira aproximacao aos valores normativos, com base no SF-6D, para aquele tipo de doentes. Pretende-se ainda averiguar a capacidade de medidas genericas de medicao da QdVRS distinguirem grupos em termos de caracteristicas sociodemograficas. Aplicaram-se, por entrevista pessoal, as versoes portuguesas do EQ-5D, do SF-6D, do AQLQ(S) e do ACQ a uma amostra representativa da populacao portuguesa com asma. A maioria dos individuos nao apresentou problemas significativos nas dimensoes medidas, excepto na funcao fisica, onde os individuos reportaram limitacoes moderadas. Em media, os inquiridos apresentam valores de utilidade de 0,86. Os homens, os mais jovens, os solteiros, os individuos com habilitacoes literarias mais elevadas, os empregados, os individuos com rendimentos mais elevados e aqueles que residiam em zonas urbanas foram os que reportaram niveis de utilidade mais elevados. Por outro lado, os individuos que se encontravam num estadio mais avancado da doenca reportaram, como era de esperar, niveis medios de utilidade inferiores aos dos que se encontravam num estadio menos grave da doenca. Foram obtidos valores normativos para o SF-6D para doentes com asma por genero, grupo etario, estado civil, habilitacoes literarias, situacao profissional, local de residencia e rendimento medio mensal liquido. As medidas de utilidade baseadas em preferencias utilizadas neste estudo discriminam adequadamente grupos de doentes com asma, de acordo com grupos sociodemograficos. Os valores normativos obtidos podem ser usados em estudos de avaliacao economica e estudos clinicos, uma vez que incorporam as preferencias dos doentes e traduzem a utilidade atribuida ao seu estado de saude. Rev Port Pneumol 2010; XVI (1): 23-55

Utilização do SF-6D na medição das preferências dos portugueses: sistema de valores e normas da população dos 18 aos 64 anos

Resumo Introducao Existe um interesse crescente no estudo da variacao entre paises das valoracoes dos estados de saude e alguma evidencia recente sugere que os resultados de um pais nao tem necessariamente que ser transferidos para outros paises. Nos ultimos tempos tem-se assistido ao desenvolvimento de sistemas de valores dos instrumentos de medicao de preferencias mais utilizados, como o EQ-5D, o HUI e o SF-6D. Recentemente foi publicado um artigo com o sistema portugues de valores do SF-6D. No entanto, esse sistema de valores apresentava incoerencias ao nivel dos pesos de alguns niveis das seis dimensoes do SF-6D. A correccao das incoerencias permitiria melhora-lo. O objectivo deste artigo e apresentar o sistema portugues de valores do SF-6D agora livre de incoerencias e determinar as respectivas normas da populacao portuguesa dos 18 aos 64 anos. Metodologia Foram identificados os niveis das dimensoes que tinham incoerencias. Esses niveis foram agregados e estimaram-se modelos parcimoniosos pelas equacoes de estimacao generalizadas. As normas portuguesas para os individuos com idades compreendidas entre os 18 e os 64 anos para o SF-6D foram obtidas a partir da aplicacao dos resultados do melhor modelo parcimonioso aos dados de uma amostra aleatoria da populacao portuguesa dos 18 aos 64 anos ( n = 2.459) a quem tinha sido aplicado o SF-36v2. Resultados A agregacao de alguns niveis do SF-6D onde se verificavam incoerencias permitiu obter um sistema portugues de valores para o SF-6D. No entanto, ainda se verificam problemas ao nivel da subestimacao nalguns estados de saude graves. A utilidade media dos estados de saude da populacao activa portuguesa situou-se em 0,81 (associada a um desvio padrao de 0,12). Calcularam-se as normas portuguesas do SF-6D relativas a populacao dos 18 aos 64 anos por genero, grupo etario, estado civil e nivel habilitacional, tendo-se observado valores mais baixos de utilidade nas mulheres, nos individuos mais velhos, nos individuos com um nivel mais baixo de instrucao, nos viuvos e nos individuos residentes em zonas rurais. Conclusao Esta investigacao demonstra que e possivel obter sistemas de pesos para a medicao da qualidade de vida relacionada com a saude. Este modelo melhora significativamente os resultados apresentados anteriormente, embora ainda subsistam limitacoes ao nivel da subestimacao nalguns estados de saude graves. As normas portuguesas sao uteis para contextualizar os valores obtidos pelo SF-6D e permitir uma interpretacao dos resultados de investigacao obtidos.

Are condition-specific utilities more valid than generic preference-based ones in asthma? Evidence from a study comparing EQ-5D-3L and SF-6D with AQL-5D

ABSTRACT Background: Systematic discrepancies have been shown in utility values derived from different instruments. This study compares utilities from the condition-specific AQL-5D and the generic EQ-5D-3L and SF-6D in an asthmatic population with heterogeneous health-related quality of life (HRQoL), disease severity, and control status. Methods: A consecutive sample of 104 patients diagnosed with asthma completed a survey containing the Greek versions of SF-36, EQ-5D-3L, and AQLQ(s). Treatment adequacy was assessed with the Asthma Control Questionnaire (ACQ), and asthma severity according to Global Initiative for Asthma 2016 guidelines. Association and agreement between instruments were assessed with Spearman’s correlation and Bland–Altman plots. Results: AQL-5D utilities exceeded (p < 0.001) those from EQ-5D-3L and SF-6D. There were weak-to-moderate correlations (<0.5) between most dimensions of AQL-5D, and those of EQ-5D-3L and SF-6D, and strong correlations between similar dimensions of EQ-5D-3L and SF-6D. Significant differences (p < 0.001) were observed throughout the visual analog scale (VAS), asthma severity and asthma control subgroups, with AQL-5D consistently higher than EQ-5D-3L and SF-6D. Conclusions: All instruments distinguished between differing degrees of asthma control, but only AQL-5D discriminated between asthma severity and HRQoL as well. Although the relatively small sample warrants caution in interpreting the subgroup results, this study contributes to the growing number of comparisons between condition-specific and generic preference-based instruments.

A utilização da experiência de escolha discreta na valoração de estados de saúde

Discrete Choice Experiment (DCE) is a technique for preferences elicitation that recently started to be used in health economics. This study aimed to identify and describe the stages of design construction of this technique and to assess their implementation in health economics papers that address the elicitation of health state values. Published research studies were selected implementing DCE in the valuation of health status. All nine evaluated studies explain the five main: identification of attributes, identification of levels of attributes, experimental design, data collection and analysis. The analysis performed evidenced that the DCE building steps are in general followed.

Transthyretin Familial Amyloid Polyneuropathy Impact on Health-Related Quality of Life.

PSY78 InPatIent Burden among PatIentS WIth CYStIC FIBroSIS Who are homozYgouS For the F508del mutatIon Hodgkins P1, Ayyagari R2, Guo J2, Wagener J3, O’Sullivan AK1 1Vertex Pharmaceuticals, Boston, MA, USA, 2Analysis Group, Inc, Boston, MA, USA, 3University of Colorado, Aurora, CO, USA Objectives: To examine inpatient utilization among patients with cystic fibrosis (CF) and homozygous for the F508del CFTR gene mutation. MethOds: Medical chart data from patients with CF ≥ 12 years old were collected in France, Germany, Italy, Spain, Australia and Canada. Demographics and clinical characteristics were obtained for a 12-month baseline period and a follow-up period ranging from 2-36 months. Proportions of patients hospitalized, hospitalization rates, and length of stay were assessed overall and by age (12-17, ≥ 18 years), lung function (percent predicted forced expiratory volume in 1 second [ppFEV1] ≥ 70%, 41-69%, ≤ 40%), and country. Results: Data for 523 patients were included. Baseline mean ± SD age was 24.8 ± 9.5 years and mean ± SD ppFEV1 was 67.1 ± 22.9%. Over a mean of 27 months follow-up, 19% of patients had 1 hospitalization, 11% had 2, and 37% had ≥ 3. The mean ± SD rate of hospitalizations was 1.2 ± 1.5 per patient-year. In the follow-up period, the proportion of patients with at least 1 hospitalization and the rate of hospitalization were highest for the severe ppFEV1 group relative to moderate and mild groups (86%, 73%, and 55% and 2.1 ± 2.0, 1.4 ± 1.6 and 0.7 ± 1.1 per patient-year respectively). The overall mean length of stay was 10.7 ± 7.5 days; it was 9.2 ± 6.8 days for the mild lung function group vs 11.0 ± 6.7 days for the severe group. The hospitalization rate ranged from 0.6 ± 1.1 per patient-year in Spain to 1.7 ± 1.9 in Australia; trends by lung function were consistent across countries. cOnclusiOns: Patients with CF and homozygous for the F508del CFTR gene mutation have high rates of hospitalization. Hospitalization rate varies by country, but is consistently higher for patients with the lowest lung function, congruent with a progressive disease.