We recommend a framework for the BIA, provide guidance on the acquisition and use of data, and offer a common reporting format that will promote standardization and transparency. Adherence to these good research practice principles would not necessarily supersede jurisdiction-specific BIA guidelines but may support and enhance local recommendations or serve as a starting point for payers wishing to promulgate methodology guidelines.

Objectives: The objective of this study was to evaluate the methodological characteristics of cost-effectiveness evaluations carried out in Spain since 1990 which include LYG as an outcome to measure the incremental cost-effectiveness ratio. Methods: A systematic review of published studies was conducted describing their characteristics and methodological quality. We analyze the cost per LYG results in relation with a commonly-accepted Spanish cost effectiveness threshold and the possible relation with the cost per quality adjusted life year (QALY) gained when they were both calculated for the same economic evaluation. Results: A total of 62 economic evaluations fulfilled the selection criteria, 24 of them including the cost per QALY gained result as well. The methodological quality of the studies was good (55%) or very good (26%). A total of 124 cost per LYG results were obtained with a mean ratio of 49,529€ and a median of 11,490€ (standard deviation of 183,080). Since 2003, a commonly-accepted Spanish threshold has been referenced by 66% of studies. A significant correlation was found between the cost per LYG and cost per QALY gained results (0.89 Spearman-Rho, 0.91 Pearson). Conclusions: There is an increasing interest for economic healthcare evaluations in Spain and the quality of the studies is also improving. Although a commonly-accepted threshold exists, further information is needed for decision making as well as to identify the relationship between the costs per LYG and per QALY gained.Response to Reviewers: We decided to give response to specific reviewer and editor comments in this box and uploading the corresponding attachment file as well.

(*) Tanto el desarrollo como la elaboración del modelo ha sido financiado por una beca no finalista otorgada por Medtronic Ibérica S.A. a CORE Research, quien ha llevado a cabo los análisis en todo momento y con total autonomía. RESUMENFundamento: El uso de bombas de infusión continua de insulina (BICI) para la diabetes mellitus tipo 1 (DM1) se ha relacionado con un mejor control metabólico al compararlo con las múltiples dosis de insulina (MDI). Este mejor control puede traducirse en una disminución de las complicaciones asociadas a la DM1 y por lo tanto una reducción de los costes asociados. Sin embargo el uso de esta terapia ha quedado mermado, al menos en parte, debido a su mayor coste inicial de adquisición. El objetivo del presente estudio fue estimar las consecuencias clínicas y económicas del uso de BICI frente a MDI a través de un análisis de coste-utilidad.Métodos: Se adaptó un modelo matemático de simulación que emplea datos clínicos y económicos de ámbito nacional, para simular las consecuencias clínicas y económicas a largo plazo de un paciente con DM1. El horizonte temporal fue el de toda la vida del paciente, incluyendo sólo costes directos sanitarios, y actualizando tanto costes como beneficios a una tasa del 3% anual.Resultados: En el caso base los pacientes tratados con BICI experimentaron una ganancia de vida de 0,890 años (p<0,05) y 0,852 AVACs (p<0,05). El tratamiento con BICI produce un coste medio incremental de 25.523 ? (p<0,05) por paciente tratado, lo que nos condujo a un ratio coste-utilidad incremental de 29.947 ?/AVAC [IC 95% (29.519, 30.375)].Conclusiones: La mejora en el control glucémico en pacientes con BICI se asoció a una reducción del coste global del manejo de pacientes con DM1, y resultó tener una relación coste-utilidad favorable al compararla con el tratamiento convencional MDI.Palabras clave: Diabetes mellitus Tipo 1. Coste-utilidad. Bombas de insulina. Modelo Económico. ABSTRACT Cost-Utility Analysis of Iinsulin Pumps Compared to Multiple Daily doses of Insulin in Patients with Type 1 Diabetes Mellitus in SpainBackground: The use of continuous subcutaneous insulin infusion (CSII) for treating Type I diabetes mellitus (DM1) has been related to better metabolic control compared it to daily multiple insulin injections (DMI) and thus to a lowering of the related costs. However, this therapy is now being used to a lesser extent due, at least partially, to the higher initial cost of purchase. This study is aimed at estimating the clinical and economic consequences of using CSII as compared to DMI by means of a cost-utility analysis.

The use of mathematical models to assess therapeutic alternatives is increasing in the economic evaluation of health technologies and services and these models are becoming an increasingly important aid to decision making in health care. Until now, 2 types of model have been used, depending to some extent on the disease to be studied: decision trees have been used for acute diseases and Markov models in chronic or recurrent diseases. However, both models present major limitations when addressing complex processes or diseases. Consequently, interest in, and the use of, discrete-event simulation is growing. The present article aims to describe the main characteristics of discrete-event simulation, the state of the art in this field, and the advantages of these models with respect to other kinds of models in health economics, especially in the evaluation of health technologies and product assessment.

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