Servicio Canario de la Salud

Full title: Cost-effectiveness of the expanded newborn screening of congenital errors of metabolism using tandem mass spectrometry

Authors: Castilla I, Arvelo-Martín A, Valcárcel-Nazco C, Linertová R, Serrano-Aguilar P, Ruiz-Pons M, Posada M, Dulín-Íñiguez E, Espada M, Zubizarreta R.

Contact person: Iván Castilla Rodríguez (ivan.castillarodriguez@sescs.es)

Introduction

The incorporation of tandem mass spectrometry to neonatal screening for inborn errors of metabolism has opened the door for expanding those screening programs since, potentially, a large number of diseases may be efficiently screened. However, for many of these diseases, the evidence of the benefit of early detection is still scarce or nonexistent.

Objectives

To determine the efficiency of incorporating five new diseases to a screening program that already uses tandem mass spectrometry for the early detection of MCADD and PKU. These new congenital conditions are homocystinuria, LCHADD, maple syrup urine disease, isovaleric acidemia and glutaric aciduria type 1.

Method

We have developed a decision tree model with two main branches. The first branch incorporates a new pathology to the screening program, whereas the second branch assumes that this condition is not being screened. The same model is used sequentially to estimate the efficiency in terms of cost-effectiveness of incorporating new pathologies, each time adding the accumulated cost and effectiveness of previous pathologies. The analysis incorporates the social perspective, presenting the lifetime costs and effects for the newborns studied. The measure of effectiveness is life-years gained, which have been discounted, as the costs, at a rate of 3%. Costs were expressed as 2012 euros. We performed a multivariate and stochastic sensitivity analysis by means of Monte Carlo simulations, allowing us to compute the acceptability curves and the expected value of perfect information.

Results

The implementation of a screening program for PKU and MCADD using tandem mass spectrometry has an incremental cost of € 3.93 [confidence interval 95%: € 3.02, € 4.71] and an incremental effectiveness of 0.00017 life-years gained [0.00011, 0.00026] by newborn, resulting an incremental cost-effectiveness ratio of 22,774.96 €/AVG [11,734.34, 44,517.73]. Incorporating five new pathologies to this screening program involves an incremental cost of € 11.62 [€ 6.04, € 17.23], and an incremental effectiveness of 0.00042 LYG [0.00028, 0.00057], resulting an incremental cost-effectiveness ratio of 27,607.38 €/AVG [10,567.35, 62,628.36].

Conclusions

The expanded newborn screening program to the five selected pathologies is efficient, on average, for a willingness to pay of 30,000 €/LYG. However, the high uncertainty surrounding the results points to the desirability of further research to reduce the variability in the parameter estimates and increase the robustness of the findings.