Application of adjusted limited dependent variable mixed model in the mapping of pharmacoeconomic health utility scale / 中国药房

OBJ ECTIVE To introduce adjusted limited dependent variable mixed model （ALDVMM）and study its application in mapping research ，so as to provide reference for pharmacoeconomic evaluation that needs to obtain health utility value through mapping. METHODS Using the method of literature research ，ALDVMM was introduced from the aspects of development background，model principle ，model determination and test ，model advantages and the current application of the model in empirical research. RESULTS & CONCLUSIONS ALDVMM is a mixed model developed by foreign scholars for the truncation and multimodality phenomenon of EuroQoL group ’s 5D（EQ-5D）at the health utility value 1. Compared with the traditional model，ALDVMM is feasible and has more advantages ，and can more effectively and flexibly capture the actual distribution of EQ-5D and deal with the boundary value problem ，which is helpful to obtain the health utility value more accurately and efficiently and carry out high-quality pharmacoeconomic evaluation.

Modelagem estatística: perguntas que você sempre quis fazer, mas nunca teve coragem / Statistical modeling: questions you have always wanted to ask but never had the courage to

Dando continuidade aos artigos da série "Perguntas que você sempre quis fazer, mas nunca teve coragem", que tem como objetivo responder e sugerir referências para o melhor entendimento das principais dúvidas dos pesquisadores do Hospital de Clínicas de Porto Alegre sobre estatística, este quarto artigo se propõe a responder às principais dúvidas levantadas sobre modelagem estatística. São discutidas questões referentes à classificação de variáveis em independentes e dependentes, diferenças entre correlação, associação e regressão, os principais tipos de regressão e quais etapas são necessárias na construção de modelos. Os conceitos são abordados numa linguagem acessível ao público leigo e diversas referências são sugeridas para os curiosos em relação ao tema. (AU)

Continuing the series of articles "Questions you have always wanted to ask but never had the courage to," which aims to answer the most common questions of researchers at Hospital de Clínicas de Porto Alegre regarding statistics and to suggest references for a better understanding, this forth article addresses the topic of statistical modeling. Questions about classification of variables as dependent or independent, differences between correlation, association and regression, types of regression and steps for statistical modeling are discussed. The concepts are explained in plain language for lay readers and several references are suggested for those curious about the topic. (AU)

Significance of Time-dependent Exposure Variable in Occupational Disease Study / 대한산업의학회지

Although the final cumulative exposure has been used as a exposure variable on the cohort study for the relation between exposure and disease, the bias from the use of fixed exposure can be developed because the exposure amount changes across the time. We developed the program to handle the Cox model with irregularly changing time-dependent exposure variable and covariates, and the validity about the application of time-dependent exposure variable and lagged interval was practically evaluated by analyzing the data collected for typical retrospective cohort study with that program. The results were as follows : The exposure-response relations between the deaths from lung cancer and exposures (fixed or time-dependent) were not clear when 0 year lagged interval was applied. When 15 years lagged interval was applied, the exposure-response relations between the deaths from lung cancer and the time-dependent exposures to crystalline silica were observed and relative risky increased like 1.00, 1.17, 1.30 and 2.45 across the exposure levels. The relative risk estimates for lung cancer with time-dependent exposure variable were higher than those with fixed exposure variable without regard to the application of lagged interval. The exposure-response relations between the deaths from non-malignant respiratory disease (NMRD) and exposures (fixed or time-dependent) were observed across exposure levels when 0 year lagged interval was applied. When 15 years lagged interval wag applied, the exposure-response relations between the deaths from NMRD and the time-dependent exposures to crystalline silica were observed, but were not with fixed exposure variable. The relative risk estimates for NMRD mortality with time-dependent exposure variable were higher than those with fixed exposure variable, and the application of lagged interval on the evaluation of NMRD mortality was meaningless. The results suggests that the application of time-dependent exposure variable on the study of exposure-effect relation should be considered and the application of lagged interval should be decided according to the time needed from disease detection to death.