scholarly journals Weighted mixed-effects dose–response models for tables of correlated contrasts

Author(s):  
Nicola Orsini

Recognizing a dose–response pattern based on heterogeneous tables of contrasts is hard. Specification of a statistical model that can consider the possible dose–response data-generating mechanism, including its variation across studies, is crucial for statistical inference. The aim of this article is to increase the understanding of mixed-effects dose–response models suitable for tables of correlated estimates. One can use the command drmeta with additive (mean difference) and multiplicative (odds ratios, hazard ratios) measures of association. The postestimation command drmeta_graph greatly facilitates the visualization of predicted average and study-specific dose–response relationships. I illustrate applications of the drmeta command with regression splines in experimental and observational data based on nonlinear and random-effects data-generation mechanisms that can be encountered in health-related sciences.

2012 ◽  
Vol 14 (3) ◽  
pp. 420-432 ◽  
Author(s):  
Elodie L. Plan ◽  
Alan Maloney ◽  
France Mentré ◽  
Mats O. Karlsson ◽  
Julie Bertrand

Dose-Response ◽  
2021 ◽  
Vol 19 (4) ◽  
pp. 155932582110627
Author(s):  
Linqian Yang ◽  
Jiaying Wang ◽  
Robert A. Cheke ◽  
Sanyi Tang

Purpose Dose-response curves, which fit a multitude of experimental data derived from toxicology, are widely used in physics, chemistry, biology, and other fields. Although there are many dose-response models for fitting dose-response curves, the application of these models is limited by many restrictions and lacks universality, so there is a need for a novel, universal dynamical model that can improve fits to various types of dose-response curves. Methods We expand the hormetic Ricker model, taking the delay inherent in the dose-response into account, and develop a novel and dynamic delayed Ricker difference model (DRDM) to fit various types of dose-response curves. Furthermore, we compare the DRDM with other dose-response models to confirm that it can mimic different types of dose-response curves. Data analysis By fitting various types of dose-response data sets derived from drug applications, disease treatment, pest control, and plant management, and comparing the imitative effect of the DRDM with other models, we find that the DRDM fits monotonic dose-response data well and, in most circumstances, the DRDM has a better imitative effect to non-monotonic dose-response data with hormesis than other models do. Results The MSE of fits of the DRDM to S-shaped dose-response data (DS2-G) is not lower than those for four other models, but the MSE of fits to U-shaped (DS7) and inverted U-shaped dose-response data (DS10) were lower than for two other models. This means that the imitative effect of the DRDM is comparable to other models of monotonic dose-response data, but is a significant improvement compared to traditional models of non-monotonic dose-response data with hormesis. Conclusion We propose a novel dynamic model (DRDM) for fitting to various types of dose-response curves, which can reflect the dynamic trend of the population growth compared with traditional static dose-response models. By analyzing data, we have confirmed that the DRDM provides an ideal description of various dose-response observations and it can be used to fit a wide range of dose-response data sets, especially for hormetic data sets. Therefore, we conclude that the DRDM has a good universality for dose-response curve fitting.


Author(s):  
Anna-Maija Talvitie ◽  
Hanna Ojala ◽  
Teuvo Tammela ◽  
Ilkka Pietilä

Abstract Introduction This study investigates comments that prostate cancer patients spontaneously write in the margins of the Expanded Prostate Cancer Index Short Form (EPIC-26) questionnaire. We aim to show the possible barriers that patients face while answering the survey, and to consider how these barriers may affect the response data generated. We investigate the kind of information patients’ comments on EPIC-26 contain, and patients’ motivations to provide this information. We also study why some EPIC domains spark more comments than others. Method We analyzed 28 pages of transcribed comments and four pages of supplementary letters from our survey participants (n = 496). Using inductive content analysis, we generated 10 categories describing the content of participants’ comments, and four themes demonstrating their motives for commenting. The comments regarding each EPIC domain were quantified to discover any differences between domains. Results The sexual domain of EPIC-26 provoked over half of all comments. Patients without recent sexual activity or desire had difficulties answering sexual function questions 8–10. The lack of instructions on whether to take erectile aid use into account when answering erectile function questions led to a diversity of answering strategies. Patients with urinary catheters could not find suitable answer options for questions 1–4. All domains sparked comments containing additional information about experienced symptoms. Conclusion Patients are mainly willing to report their symptoms, but a lack of suitable answer options causes missing data and differing answering strategies in the sexual and urinary domains of EPIC-26, weakening the quality of the response data received.


2004 ◽  
Vol 67 (9) ◽  
pp. 2024-2032 ◽  
Author(s):  
FUMIKO KASUGA ◽  
MASAMITSU HIROTA ◽  
MASAMICHI WADA ◽  
TOSHIHIKO YUNOKAWA ◽  
HAJIME TOYOFUKU ◽  
...  

The Ministry of Health, Labor and Welfare (former MHW) of Japan issued a Directive in 1997 advising restaurants and caterers to freeze portions of both raw food and cooked dishes for at least 2 weeks. This system has been useful for determining vehicle foods at outbreaks. Enumeration of bacteria in samples of stored food provide data about pathogen concentrations in the implicated food. Data on Salmonella concentrations in vehicle foods associated with salmonellosis outbreaks were collected in Japan between 1989 and 1998. The 39 outbreaks that occurred during this period were categorized by the settings where the outbreaks took place, and epidemiological data from each outbreak were summarized. Characteristics of outbreak groups were analyzed and compared. The effect of new food-storage system on determination of bacterial concentration was evaluated. Freezing and nonfreezing conditions prior to microbial examination were compared in the dose-response relationship. Data from outbreaks in which implicated foods had been kept frozen suggested apparent correlation between the Salmonella dose ingested and the disease rate. Combined with results of epidemiological investigation, quantitative data from the ingested pathogen could provide complete dose-response data sets.


2019 ◽  
Vol 222 (2) ◽  
pp. 249-259 ◽  
Author(s):  
Mihai Zamfir ◽  
Doris G. Gerstner ◽  
Sandra M. Walser ◽  
Jürgen Bünger ◽  
Thomas Eikmann ◽  
...  

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