Table 3.

Occurrence of different categories of drug-related problems (DRPs) for drugs used on hospital admission in patients using ≥ 5 drugs and patients using <5 drugs on admission

Type of DRP	Group 1: ≥ 5 drugs on admission, n = 2840 drugs on admission, 391 patients % of drugs causing DRP (no. of DRPs)	Group 2: <5 drugs on admission, n = 934 drugs on admission,436 patients % of drugs causing DRP (no. of DRPs)	Difference between groups
			95% CI *	P-values†
Need for additional drug	0.2 (6)	0.2 (2)	0 (−0.3, 0.3)	0.99
Unnecessary drug	2.4 (69)	1.9 (18)	0.5 (−0.5, 1.6)	0.37
Non-optimal drug	3.4 (97)	2.7 (25)	0.7 (−0.5, 2.0)	0.27
Non-optimal dose	7.1 (202)	7.1 (66)	0.0 (−1.9, 1.9)	0.96
Drug interaction	3.4 (96)	2.2 (21)	1.2 (−0.0, 2.3)	0.08
Need for monitoring	3.3 (93)	3.9 (36)	−0.6 (−2.0, 0.8)	0.40
No further need for drug	0.7 (20)	0.8 (7)	−0.1 (−0.7, 0.6)	0.89
Medical chart error	2.7 (77)	3.9 (36)	−1.2 (−2.5, 0.2)	0.08
Therapy discussion	1.9 (53)	2.2 (21)	−0.3 (−1.5, 0.7)	0.46
Patient adherence	0.7 (21)	1.3 (12)	−0.6 (−1.3, 0.2)	0.12
Patient education	1.0 (29)	1.8 (17)	−0.8 (−1.7, 0.1)	0.054
Adverse drug reaction	1.3 (37)	2.0 (19)	−0.7 (−1.7, 0.3)	0.11

^*95% confidence interval for the difference between groups, given in percentage.

^†Significant when P < 0.05. Low numbers were found for the DRPs others: 0.2% (6) vs. 0.7% (7) in group 1 and group 2, respectively.