We investigated heterogeneity among subgroups based on study quality,
study setting, study methodology, and study population. Since there was
very high heterogeneity in each subgroup, no meta-analysis by subgroup
was performed. Heterogeneity and summary proportions, by subgroup, are
presented in the supplement.
One study, reported only in two conference
abstracts44,45, was a low-quality report of a
spontaneous ADR reporting system in the medical wards of a Nigerian
hospital, where 30/2012 (1.5%) patients were reported to have had an
ADR-related admission.
The remaining thirteen studies were all conducted as active surveillance
studies, eight of which were in
adults37-39,41-43,47,49,50,52, four in
children36,40,51,53, and one in a mixed adult and
paediatric population48. As this latter study
presented data for adults and children separately, we could extract
separate adult and paediatric datasets from it. Key results from Group 1
studies, grouped by the ADR detection method (spontaneous reporting vs
active surveillance) and study population (adults vs children) are
presented in Table 3.