Table 5

Known groups validity of MRB-QoL subscales

MRB-QoL subscales	Subgroups	Median (IQR)	Difference between subgroups: P value†
Routine and Regimen Complexity	All patients (n=363)	24 (15–33)
	> 5 number of medicines (n=197)	25 (17–35)	<0.01*
	<5 number of medicines (n=161)	23 (14–30)	<0.01*
	> 3 conditions (n=193)	25 (17–33)	0.02*
	<3 conditions (n=168)	22 (14–32)	0.02*
	Age >65 years (n=174)	20 (13–25)	<0.01*
	Age <65 (n=189)	29 (22–38)	<0.01*
	Male (n=185)	24 (16–34)	0.43
	Female (n=178)	23 (15–33)	0.43
	DBI 0 (n=131)	19 (11–28)	<0.01*
	DBI >0 (n=147)	25 (17–33)	<0.01*
Psychological Burden	All patients (n=363)	21 (16–24)
	> 5 number of medicines (n=196)	21 (17–24)	0.03*
	<5 number of medicines (n=162)	20 (14–24)	0.03*
	> 3 conditions (n=192)	22 (17–25)	0.01*
	<3 conditions (n=169)	19 (15–24)	0.01*
	Age >65 years (n=174)	19 (12–22)	<0.01*
	Age <65 (n=189)	22 (18–25)	<0.01*
	Male (n=185)	21 (16–24)	0.74
	Female (n=178)	21 (16–24)	0.74
	DBI 0 (n=131)	19 (12–23)	<0.01*
	DBI >0 (n=147)	22 (18–25)	<0.01*
Functional and Role Limitation	All patients (n=351)	19 (14–24)
	> 5 number of medicines (n=190)	20.5 (15–25)	<0.01*
	<3 number of medicines (n=156)	18 (12–23.8)	<0.01*
	> 3 conditions (n=186)	20 (15–25)	0.05*
	<3 conditions (n=163)	18 (14–24)	0.05*
	Age >65 years (n=174)	16 (14–21)	<0.01*
	Age <65 (n=189)	22 (17–28)	<0.01*
Therapeutic Relationship	All patients (n=367)	6 (4–9)
	> 5 number of medicines (n=200)	6 (4–10)	<0.01*
	<5 number of medicines (n=162)	6 (3–7)	<0.01*
	> 3 conditions (n=195)	6 (4–9)	0.02*
	<3 conditions (n=170)	6 (3–8)	0.02*
	Age >65 years (n=176)	5 (3–6)	<0.01*
	Age <65 (n=191)	7 (5–10)	<0.01*
	Male (n=183)	6 (4–9)	0.04*
	Female (n=175)	6 (3–8)	0.04*
	DBI 0 (n=132)	6 (3–7)	0.02*
	DBI >0 (n=148)	6 (4–8)	0.02*
Social Burden	All patients (n=358)	9 (6–13)
	> 5 number of medicines (n=195)	9 (6–14)	0.14
	<5 number of medicines (n=158)	9 (5–13)	0.14
	> 3 conditions (n=190)	10 (7–14)	0.12
	<3 conditions (n=166)	9 (5.8–13)	0.12
	Age >65 years (n=171)	8 (4–10)	<0.01*
	Age <65 (n=187)	12 (8–16)	<0.01*
	Male (n=183)	10 (6–13)	0.67
	Female (n=175)	9 (6–13)	0.67
	DBI 0 (n=130)	8 (4–12)	<0.01*
	DBI >0 (n=145)	9 (8–13)	<0.01*

*A P value of 0.05 was considered statistically significant.
†Differences between subgroups (mean rank score) were examined using a Mann-Whitney U test.
DBI, Drug Burden Index; MRB-QoL, Medication-Related Burden Quality of Life.