Event simulation and external validation applied in published health economic models for obesity: a systematic review

Abstract

This study aims to determine methodological variations in the event simulation approaches of published health economic decision models, in the field of obesity, and to investigate whether their predictiveness and validity were investigated via external event validation techniques, which investigate how well the model reproduces reality. Areas covered: A systematic review identified a total of 87 relevant papers, of which 72 that simulated obesity-associated events were included. Most frequently simulated events were coronary heart disease (≈ 83%), type 2 diabetes (≈ 74%), and stroke (≈ 66%). Only for ten published model-based health economic assessments in obesity an external event validation was performed (14%; 10 of 72), and only for one the predictiveness and validity of the event simulation was investigated in a cohort of obese subjects. Expert commentary: We identified a wide range of obesity related event simulation approaches. Published obesity models lack information on the predictive quality and validity of the applied event simulation approaches. Further work on comparing and validating these event simulation approaches is required to investigate their predictiveness and validity, which will offer guidance future modelling in the field of obesity.

Replication of Published Health Economic Obesity Models: Assessment of Facilitators, Hurdles and Reproduction Success

“…Based on a previous systematic review identifying 87 health economic obesity models [7,8], the models for replication were selected using an expert panel consensus [9]. The panel assessed the key structural modeling approaches applied in published obesity models, and provided an expert consensus to improve the methodology and consistency of the application of decision-analytic modeling in obesity research.…”

“…Consequently, complex modeling frameworks simulated over long-term horizons are required, and these carry the potential risk of errors by the modeler and/or misinterpretations by the reader. In order to investigate the reproducibility of results in this context, we have selected health economic obesity models for replication, on the basis of a previously published systematic review [7,8] and on the basis of previously published structural quality criteria for health economic obesity models [9]. The field of obesity modeling is in general very diverse; this is driven by multiple preventive and therapeutic approaches and multiple complications and comorbidities, which have triggered the development of various unique modeling approaches.…”

“…This observed difference might also be based on the fact that there are currently no attempts to align, compare, and validate obesity modeling approaches, such as the still ongoing Mount Hood challenge for type 2 diabetes [11][12][13]. Furthermore, it was found that most of these unique obesity models lack an external event validation [8], making the replication of obesity models specifically an interesting research exercise.…”

Identification and expert panel rating of key structural approaches applied in health economic obesity models

“…Such evaluations allow decision makers to make an informed judgement on the health economic impact of an intervention, by assessing the additional benefits of funding an intervention relative to its additional costs [7]. As shown in systematic reviews [8,9] decision analytic modelling has commonly been used to evaluate the longterm economic consequences of obesity prevention and therapy measures. In the context of these obesity related decision models the key structural aspects are of fundamental influence as they are impacting all outcomes simulated by the model, including clinical parameters & events, quality of life, direct and indirect costs and hence the whole spectrum of relevant economic consequences [10].…”

“…Previously, it was shown that there are huge variations in the structural modelling approaches focusing on the prevention and therapy of obesity [8,9] and up to now no consensus meeting on the structural aspects of obesity models has been performed. This makes it difficult for researchers to select an appropriate approach when designing a model, and subsequently for policy makers and stakeholders to assess the quality of an applied model, intended to inform political or medical decision making.…”