Sources of the utilities used in paediatric cost-utility analyses in children aged under 5 years, and the methods used in their elicitation: a systematic review.

OBJECTIVES: Few multi-attribute utility instruments (MAUIs) have been developed and validated for children under five years, limiting the evidence on health-related quality of life used to inform resource allocation decisions. This systematic review aimed to characterize utilities used in cost-utility analyses (CUAs) involving children aged 0-5 years published between 2012 and 2023, their sources, and the methods used to obtain them. METHODS: Studies were identified from the Paediatric Economic Database Evaluation (PEDE) Project. Eligible studies were CUAs reporting quality-adjusted life years (QALYs) with at least one health state for children aged 0-5 years. Descriptive analyses were conducted to summarise study characteristics, sources of utilities, and methods used to obtain utilities. Changes over time were explored by comparing studies published in 2012-2017 with 2018-2023. RESULTS: Of the 1,098 studies screened, 162 met inclusion criteria. Of these, 87 (53.7%) had health states exclusively in the 0-5 years age-group, 16 (9.9%) included states also in the 5-18 years age-group, and 59 (36.4%) included states also in adulthood. Two-thirds of CUAs evaluated were preventative interventions. Seventy percent of studies clearly reported their utility sources. Among studies that obtained utilities from the literature (82.2%), most used MAUIs, with the adult EQ-5D-3L valued using the UK tariff being most common (33%). CONCLUSIONS: CUAs involving children under five years have increased; but the methods for obtaining utilities remain varied and underreported. The frequent reliance on adult MAUIs and utilities underscores the need for validated age-appropriate instruments to improve the validity of QALY estimates in this age group.