scispace - formally typeset
Search or ask a question
Journal ArticleDOI

Indirect estimation of a discrete-state discrete-time model using secondary data analysis of regression data.

20 Jul 2009-Statistics in Medicine (John Wiley & Sons, Ltd.)-Vol. 28, Iss: 16, pp 2095-2115
TL;DR: This paper presents an approach that allows the use of published regression data in a multi- state model when the published study may have ignored intermediary states in the multi-state model, called the Lemonade Method.
Abstract: Multi-state models of chronic disease are becoming increasingly important in medical research to describe the progression of complicated diseases. However, studies seldom observe health outcomes over long time periods. Therefore, current clinical research focuses on the secondary data analysis of the published literature to estimate a single transition probability within the entire model. Unfortunately, there are many difficulties when using secondary data, especially since the states and transitions of published studies may not be consistent with the proposed multi-state model. Early approaches to reconciling published studies with the theoretical framework of a multi-state model have been limited to data available as cumulative counts of progression. This paper presents an approach that allows the use of published regression data in a multi-state model when the published study may have ignored intermediary states in the multi-state model. Colloquially, we call this approach the Lemonade Method since when study data give you lemons, make lemonade. The approach uses maximum likelihood estimation. An example is provided for the progression of heart disease in people with diabetes.

Content maybe subject to copyright    Report

Citations
More filters
Journal ArticleDOI
TL;DR: A taxonomy based on possible scenarios faced by the analyst when dealing with the available evidence is developed that can help modelers identify the most appropriate methods to use when synthesizing the available data for a given model parameter.

46 citations

Journal ArticleDOI
TL;DR: A new computer tool designed for chronic disease modeling is described and the modeling capabilities of this tool were used to model the Michigan model for diabetes.

34 citations

Journal ArticleDOI
TL;DR: A likelihood approach to correctly model the design of clinical studies under the conditions where 1) the theoretical model may include an instantaneous state of distinct interest to the researchers, and 2) the study design may be such that study data can not be used to estimate a single parameter in the theoreticalmodel of interest.

16 citations

Dissertation
01 Jan 2012
TL;DR: In this paper, a taxonomy of the methodological and analytical issues in the use and synthesis of evidence for cost effectiveness modelling is presented, with guidance on appropriate synthesis methodologies to use and identifying areas where further methodological contributions are needed.
Abstract: Health care economic evaluations assess the costs and consequences of competing interventions, programmes or services. Such assessments use a decision model, with parameters informed by available evidence. Evidence, however, is rarely derived from a single source, in which case researchers are expected to combine information on multiple sources. This thesis contributes to the methodological debate on the use of evidence, particularly, the use of individual level data (IPD), for cost effectiveness analysis. This thesis defines a taxonomy which summarises the methodological and analytical issues in the use and synthesis of evidence for cost effectiveness modelling. For alternative parameter types (e.g. relative effectiveness, costs) the taxonomy offers guidance on appropriate synthesis methodologies to use and identifies areas where further methodological contributions are needed. The thesis also explores methods of synthesis of IPD and develops novel frameworks which allow both IPD and AD to be jointly modelled, specifically in estimating relative effectiveness. The use of IPD from studies is found desirable, particularly when the estimation of subgroup effects is of interest. An applied decision model of the cost effectiveness of smoke alarm equipment in households with pre-school children is developed within this thesis. This application offers a means to evaluate the impact of using IPD on the cost effectiveness outcomes, compared to the use of AD. The thesis examines the advantages of having access to IPD when quantifying decision uncertainty. Additionally, it discusses the use of IPD in estimating the value of further research. Specifically, a framework is used which allows considering population subgroups. It is argued that the use of IPD allows a more suitable characterisation of decision uncertainty, appropriately allowing for subgroup value of information analysis.

8 citations

PatentDOI
27 Nov 2013
TL;DR: In this article, reference disease models predict progression of disease within given populations, utilizing publically available clinical data and risk equations, to give a birds-eye view of clinical trials by allowing multiple trials to be systematically compared simultaneously via parallel processing/High Performance Computing which allows competition among alternative equations/hypothesis combinations; cross validation; and, then ranks results according to fitness via a fitness engine.
Abstract: A method wherein reference disease models predict progression of disease within given populations, utilizing publically available clinical data and risk equations, to give a birds-eye view of clinical trials by allowing multiple trials to be systematically compared simultaneously via parallel processing/High Performance Computing which allows competition among alternative equations/hypothesis combinations; cross validation; and, then ranks results according to fitness via a fitness engine.

7 citations

References
More filters
Journal ArticleDOI
TL;DR: This paper examines eight published reviews each reporting results from several related trials in order to evaluate the efficacy of a certain treatment for a specified medical condition and suggests a simple noniterative procedure for characterizing the distribution of treatment effects in a series of studies.

33,234 citations


"Indirect estimation of a discrete-s..." refers background in this paper

  • ...likelihood function of unknown parameters k(k) is Normal(k̂(k),R(k)) [17, 18]....

    [...]

Journal Article
TL;DR: In this article, the effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial were compared.

17,108 citations

Journal Article
TL;DR: The effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial were compared.

8,546 citations

22 Sep 1998
TL;DR: The effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial were compared.
Abstract: BACKGROUND Improved blood-glucose control decreases the progression of diabetic microvascular disease, but the effect on macrovascular complications is unknown. There is concern that sulphonylureas may increase cardiovascular mortality in patients with type 2 diabetes and that high insulin concentrations may enhance atheroma formation. We compared the effects of intensive blood-glucose control with either sulphonylurea or insulin and conventional treatment on the risk of microvascular and macrovascular complications in patients with type 2 diabetes in a randomised controlled trial. METHODS 3867 newly diagnosed patients with type 2 diabetes, median age 54 years (IQR 48-60 years), who after 3 months' diet treatment had a mean of two fasting plasma glucose (FPG) concentrations of 6.1-15.0 mmol/L were randomly assigned intensive policy with a sulphonylurea (chlorpropamide, glibenclamide, or glipizide) or with insulin, or conventional policy with diet. The aim in the intensive group was FPG less than 6 mmol/L. In the conventional group, the aim was the best achievable FPG with diet alone; drugs were added only if there were hyperglycaemic symptoms or FPG greater than 15 mmol/L. Three aggregate endpoints were used to assess differences between conventional and intensive treatment: any diabetes-related endpoint (sudden death, death from hyperglycaemia or hypoglycaemia, fatal or non-fatal myocardial infarction, angina, heart failure, stroke, renal failure, amputation [of at least one digit], vitreous haemorrhage, retinopathy requiring photocoagulation, blindness in one eye, or cataract extraction); diabetes-related death (death from myocardial infarction, stroke, peripheral vascular disease, renal disease, hyperglycaemia or hypoglycaemia, and sudden death); all-cause mortality. Single clinical endpoints and surrogate subclinical endpoints were also assessed. All analyses were by intention to treat and frequency of hypoglycaemia was also analysed by actual therapy. FINDINGS Over 10 years, haemoglobin A1c (HbA1c) was 7.0% (6.2-8.2) in the intensive group compared with 7.9% (6.9-8.8) in the conventional group--an 11% reduction. There was no difference in HbA1c among agents in the intensive group. Compared with the conventional group, the risk in the intensive group was 12% lower (95% CI 1-21, p=0.029) for any diabetes-related endpoint; 10% lower (-11 to 27, p=0.34) for any diabetes-related death; and 6% lower (-10 to 20, p=0.44) for all-cause mortality. Most of the risk reduction in the any diabetes-related aggregate endpoint was due to a 25% risk reduction (7-40, p=0.0099) in microvascular endpoints, including the need for retinal photocoagulation. There was no difference for any of the three aggregate endpoints between the three intensive agents (chlorpropamide, glibenclamide, or insulin). Patients in the intensive group had more hypoglycaemic episodes than those in the conventional group on both types of analysis (both p<0.0001). The rates of major hypoglycaemic episodes per year were 0.7% with conventional treatment, 1.0% with chlorpropamide, 1.4% with glibenclamide, and 1.8% with insulin. Weight gain was significantly higher in the intensive group (mean 2.9 kg) than in the conventional group (p<0.001), and patients assigned insulin had a greater gain in weight (4.0 kg) than those assigned chlorpropamide (2.6 kg) or glibenclamide (1.7 kg). INTERPRETATION Intensive blood-glucose control by either sulphonylureas or insulin substantially decreases the risk of microvascular complications, but not macrovascular disease, in patients with type 2 diabetes.(ABSTRACT TRUNCATED)

7,252 citations