Table 2.

Characteristics of studies that investigated adverse drug event-related hospitalizations

Reference	Country	Study settings	Population age (years)	Definition used	Duration (months)	Sample size (patients)	Prevalence rate (%)	Severe cases (%)	Preventability (%)
		Retrospective studies
Briant et al. [33]	New Zealand	Medical records from 13 public hospitals	Adults and elderly of mean age 58.6 years	Unintended injury, resulting in disability and caused by healthcare management rather than the underlying disease process	12	6579	1.99	NR	100*
Gurwitz et al. [32]	USA	Medical enrollees	Elderly >65 years old	An injury resulting from the use of a drug	12	30 397	5	38†	27.6
		Prospective and observational studies
Peyriere et al. [36]	France	Internal Medicine Unit A of the Saint-Eloi University Hospital, Montpellier	Adults and elderly of mean age 66.5 years (19–79 years)	An injury resulting from the use of a drug	2	156	20.5	NR	57.9
Chan et al. [37]	Australia	Royal Hobart Hospital	Elderly patients >75 years old; mean age, 81.8 years	Ocurring if one drug caused one or more adverse manifestations or if two or more drugs contributed to one adverse manifestation	2	240	30.4	15.7	53.4
Edwards et al. [34]	USA	Banner Desert Medical Center, Mesa	Adults and elderly >17 years old; mean age, 66.3 years	An injury resulting from the use of a drug	24‡	62 064	2.4	4.2§	NR
Benkirane et al. [35]	Morocco	General Teaching Hospital, Rabat	Adult population of mean age 44.3 years (18.9–59.7 years)	When a patient is unintentionally harmed as a result of drug use, including preventable and nonpreventable events	0.24	1390	4.2	2	13.2

Abbreviation is as follows: NR, not reported.

^*The study by Briant et al. investigated preventable adverse drug events in particular.

^†Considered as fatal, serious and life threatening.

^‡The incidence rate has been estimated to be in the range of 19–29% and its mean (24%) has been considered.

^§Only 4.2% (63 patients) were considered severe, of whom 49 patients died.