Table 2. Prevalence of drug interactions in hospitalized patients.

Author, year	Sample	Sample size	Average of number of drugs per patient	Prevalence of clinically manifested DDIs [%] (95% CI)
Herr et al., 1992	Patients	340	NR	1.5 (0.6–3.4)
Egger et al., 2003	Patients	163	NR	14.7 (10.1–21.0)
Blix et al., 2008	Patients	827	4.8	8.8 (7.1–11.0)
Fokter et al., 2009	Patients	323	5.0	1.2 (0.5–3.1)
Ray et al., 2010	Patients	400	9.0	64.0 (59.2–68.6)
Muñoz-Torrero et al., 2010	Patients	405	5.0	26.4 (22.4–30.9)
Marusic et al., 2013	Patients	222	NR	9.5 (6.3–14.0)
De Paepe et al., 2013	Patients	82	5.0	18.3 (11.4–28.0)
Bucşa et al., 2013	Patients	305	4.0	3.6 (2.0–6.4)
Marino et al., 2016	Patients	3473	NR	5.6 (4.9–6.4)

NR—Not reported.