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Appendix D

Cost-effectiveness of intravenous immunoglobulin (IVIG)

D.1 Introduction

The clinical evidence suggests that babies with Rhesus and ABO haemolytic disease receiving
IVIG are less likely to require exchange transfusion, an expensive procedure with associated
morbidity and mortality. 241 However, IVIG is also a relatively expensive therapeutic intervention
and there is a shortage of global supply. Therefore an economic evaluation was undertaken to
help guide GDG recommendations. The analysis compared giving IVIG as an adjunct to
phototherapy in babies with Rhesus haemolytic disease and ABO haemolytic disease where
serum bilirubin is continuing to rise at more than 8.5 micromol/litre per hour against not giving
IVIG to these babies.

D.2 Method

A simple decision-analytic model was used to assess the cost-effectiveness of IVIG as an adjunct
to multiple phototherapy in babies with haemolytic disease where bilirubin levels continue to
rise. The structure of this model is shown in Figure D.1. Costs were taken from the perspective
of the NHS and personal social services, which is in accordance with the NICE guidelines
manual (www.nice.org.uk/guidelinesmanual). 237 The cost of multiple phototherapy was not
included in the analysis as it common to both treatment alternatives. However, the costs of
exchange transfusion are important as the rationale for IVIG is that the rates of exchange
transfusion will vary according to treatment. Naturally, the costs of IVIG are also an important
cost input, as this is the treatment evaluated.
Health outcomes are measured in quality-adjusted life years (QALYs). Exchange transfusion is
associated with mortality and morbidity 241 and in this model the difference between the
treatment alternatives in QALYs is assumed to only be a consequence of mortality arising from
exchange transfusion. This was partly to simplify the analysis but also because any impact on
QALYs from morbidity would be small relative to that from assuming causation between
exchange transfusion and mortality. We assume that IVIG would have no adverse effects that
would have important long-term morbidity.

Figure D.1 Decision tree for the IVIG cost-effectiveness model

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