Criteria for considering studies for this review
We reviewed observational studies from SSA, published since 2002, which reported any of the following proportions:
Prospective or retrospective cohort studies, cross-sectional studies, as well as data collected in the baseline survey / control arm of trials were eligible for inclusion. Forty-eight countries, listed in the supplement, were defined as SSA countries in accordance with the World Bank’s use of the term. We used original study authors’ definitions of “ADR”, “hospital”, and “admission”, but we specifically did not consider attendance at an emergency unit to be a hospital admission. We only included studies conducted in unselected hospital populations. No restrictions were applied in terms of publication language or type; we included studies available as abstracts only. No restrictions were applied in terms of study population age groups.