Epidemiological burden of inborn errors of metabolism in low- and middle-income countries: a systematic review protocol.

Objective: This systematic review examines the evidence on the incidence and prevalence of inborn errors of metabolism (IEMs) in low- and middle-income countries (LMICs).

Introduction: IEMs are a set of conditions that can either be inherited or result from spontaneous mutations. Although each condition is rare in isolation, various specific disorders within the IEM group have an estimated global prevalence of 50.9 per 100,000 live births. A precise estimate of the prevalence and incidence of IEM in LMICs can help determine the necessity for extensive newborn screening programs.

Inclusion criteria: This review will cover studies conducted in LMICs, reporting on IEMs in infants and children under the age of 5 years. Studies that calculate birth prevalence and incidence of IEM will be included. Studies that provide information on the causes, clinical characteristics, treatment, case fatality rates, mortality rates, and other outcomes will also be considered.

Methods: The databases to be searched include PubMed, MEDLINE (Ovid), Embase (Ovid), CINAHL (EBSCOhost), Scopus, and gray literature sources. No date or language restrictions will be applied. Our search will encompass analytical and descriptive observational studies, which will be critically appraised by 2 independent reviewers. Data will be extracted using JBI data extraction tools. If sufficient data are available, a meta-analysis will be performed. Alternatively, if data are limited, we will present our findings in narrative format using tables and figures.

Review registration: PROSPERO CRD42023457421.