Factors Associated with Medication-Related Burden Quality of Life (MRB-QoL) in Community-Dwelling Adults with Long-Term Conditions: An Exploratory Study

Figures & data

Table 1 Characteristics of Study Participants (N=367)

Variables
Age (years), median (IQR)	64 (49–70)
Male gender, n (%)	188 (51.2)
Number of medical conditions (IQR)	3 (2–3)
Number of prescription medications (IQR)	5 (3–7)
Number of over-the-counter medications (IQR)	2 (1–3)
CCI (IQR)	3 (0–4)
MRCI (IQR)	9 (7–13)
Total DBI (IQR)	0.5 (0–0.9)
DBI >0 (IQR)	0.9 (0.7–1.6)
DBI =0, n (%)	132 (47.1)
DBI >0, n (%)	148 (52.9)

Abbreviations: CCI, Charlson Comorbidity Index; DBI, Drug Burden Index; IQR, interquartile range; MRCI, Medication Regimen Complexity Index.

Table 2 Association of Demographic and Clinical Characteristics with MRB-QoL (N=367)

Variables	R^2	β-Coefficient (Unstandardized)	p-Value
Routine and regimen complexity (RRC)
DBI	0.23	−3.04	<0.01*
CCI	0.17	0.86	<0.01*
MRCI	0.11	−0.21	0.06
Number of medical conditions	0.21	−1.54	<0.01*
Number of medications	0.22	−0.87	<0.01*
Age	0.52	3.5	<0.01*
Psychological Burden (PsyB)
DBI	0.26	−1.96	<0.01*
CCI	0.14	0.42	0.02*
MRCI	0.13	−0.14	0.03*
Number of medical conditions	0.23	−0.97	<0.01*
Number of medications	0.14	−0.32	0.01*
Age	0.32	0.12	<0.01*
Functional and Role Limitation (FRL)
DBI	0.29	−2.53	<0.01*
CCI	0.19	0.64	<0.01*
MRCI	0.05	−0.06	0.39
Number of medical conditions	0.18	−0.87	<0.01*
Number of medications	0.19	−0.52	<0.01*
Age	0.41	0.18	<0.01*
Therapeutic Relationship (TR)
DBI	0.05	−0.19	0.37
CCI	0.18	0.25	<0.01*
MRCI	0.03	0.02	0.61
Number of medical conditions	0.17	−0.35	<0.01*
Number of medications	0.20	−0.22	<0.01*
Age	0.43	0.08	<0.01*
Social Burden (SB)
DBI	0.19	−1.02	<0.01*
CCI	0.23	0.47	<0.01*
MRCI	0.02	−0.02	0.74
Number of medical conditions	0.15	−0.44	<0.01*
Number of medications	0.13	−0.21	0.03*
Age	0.50	0.14	<0.01*

Note: *p<0.05.

Abbreviations: CCI, Charlson Comorbidity Index; DBI, Drug Burden Index; MRB-QoL, Medication-Related Burden Quality of Life; MRCI, Medication Regimen Complexity Index; R², regression coefficient.

Table 3 Predictors of Medication-Related Burden Quality of Life (MRB-QoL) (N=367)

Variables	Unstandardized β-Coefficient	Standardized β-Coefficient	95% CI
Routine and Regimen Complexity (RRC): aR^2=0.32
DBI	−1.23	−0.09	−2.79	0.33
CCI	−0.44	−0.09	−0.43	0.02
MRCI	−0.20	−0.11	−1.11	0.23
Number of medical conditions	−0.15	−0.02	−1.29	1.00
Number of medications	−0.42	−0.10	−1.01	0.18
Age	0.37*	0.55*	0.29	0.45
Psychological Burden (PsyB): aR^2=0.16
DBI	−1.15*	−0.15*	−2.14	−0.16
CCI	0.02	0.01	−0.40	0.45
MRCI	−0.07	−0.07	−0.95	0.34
Number of medical conditions	−0.88*	−0.21*	−1.61	−1.50
Number of medications	0.15	0.07	−0.22	0.53
Age	0.11*	0.28*	4.13	0.01
Functional and Role Limitation (FRL): aR^2=0.21
DBI	−1.79*	−0.20*	−2.91	−0.68
CCI	−0.08	−0.02	−0.56	0.39
MRCI	0.01	0.01	−0.15	0.17
Number of medical conditions	−0.12	−0.03	−0.94	0.69
Number of medications	−0.31	−0.12	−0.73	0.11
Age	0.16*	0.37*	0.11	0.22
Therapeutic Relationship (TR): aR^2=0.20
DBI	0.22	0.05	−0.26	0.69
CCI	0.03	0.02	−0.18	0.23
MRCI	0.004	0.008	−0.06	0.07
Number of medical conditions	−0.14	−0.07	−0.48	0.21
Number of medications	−0.15	−0.13	−0.33	0.03
Age	0.08*	0.41*	0.05	0.10
Social Burden (SB): aR^2=0.26
DBI	−0.39	−0.07	−1.05	0.27
CCI	−0.02	−0.01	−0.30	0.26
MRCI	−0.03	−0.04	−0.12	0.07
Number of medical conditions	−0.22	−0.07	−0.70	0.27
Number of medications	−0.03	−0.02	−0.28	0.22
Age	0.13*	0.49*	0.09	0.17

Notes: β, regression coefficient (change in the MRB-QoL domain in relation to the independent variables in the model adjusted by the rest of the covariates). *Indicates variables with significant (p<0.05) association with MRB-QoL domains; bold values denote aR².

Abbreviations: aR², adjusted regression coefficient; CCI, Charlson Comorbidity Index; CI, Confidence Interval; DBI, Drug Burden Index; MRCI, Medication Regimen Complexity Index.

Table 4 Influence of Demographic and Clinical Characteristics on MRB-QoL (N=367)

Variables	Model I			Model II			Model III
	β (95% CI)			β (95% CI)			β (95% CI)
Routine and Regimen Complexity (RRC)
DBI	−2.69*	−4.34	−1.05	−1.72	−3.51	0.06	−1.23	−2.79	0.33
MRCI	0.01	−0.23	0.24	−0.07	−0.32	0.19	−0.20	−0.43	0.02
Number of medications	−0.76*	−0.23	0.24	−0.59	−1.27	0.09	−0.42	−1.01	0.18
Number of medical conditions				−0.73	−2.04	0.58	−0.15	−1.29	1.00
CCI				0.95*	0.27	1.63	−0.44	−1.11	0.23
Age							0.37*	0.29	0.45
aR^2	0.08			0.10			0.32
Psychological Burden (PsyB)
DBI	−1.79*	−2.74	−0.85	−1.29*	−2.31	0.28	−1.15*	−2.14	−0.16
MRCI	−0.03	−0.16	0.11	−0.03	−0.17	0.12	−0.07	−0.21	0.07
Number of medications	−0.23	−0.51	0.05	0.10	−0.29	0.49	0.15	−0.22	0.53
Number of medical conditions				−1.05*	−1.79	−0.30	−0.88*	−1.61	−1.50
CCI				0.43*	0.04	0.82	0.02	−0.40	0.45
Age							0.11*	0.06	0.16
aR^2	0.07			0.10			0.16
Functional and Role Limitation (FRL)
DBI	−2.55*	−3.63	−1.48	−2.01*	−3.19	−0.84	−1.79*	−2.91	−0.68
MRCI	0.11	−0.5	0.26	0.07	−0.10	0.23	0.01	−0.15	0.17
Number of medications	−0.47*	−0.79	−0.16	−0.39	−0.84	0.06	−0.31	−0.73	0.11
Number of medical conditions				−0.38	−1.24	0.48	−0.12	−0.94	0.69
CCI				0.53*	0.09	0.98	−0.01	−0.56	0.39
Age							0.16*	0.11	0.22
aR^2	0.10			0.12			0.21
Therapeutic Relationship (TR)
DBI	−0.21	−0.68	0.25	0.11	−0.39	0.62	0.22	−0.26	0.69
MRCI	0.06	−0.01	0.12	0.03	−0.04	0.10	0.00	−0.06	0.07
Number of medications	−0.25*	−0.39	−0.11	−0.19	−0.38	0.01	−0.15	−0.33	0.03
Number of medical conditions				−0.26	−0.63	0.11	−0.14	−0.48	0.21
CCI				0.32*	0.13	0.51	0.03	−0.18	0.23
Age							0.08*	0.05	0.10
aR^2	0.04			0.08			0.19
Social Burden (SB)
DBI	−1.06*	−1.74	−0.38	−0.56	−1.29	0.17	−0.39	−1.05	0.27
MRCI	0.06	−0.04	0.15	0.02	−0.08	0.13	−0.03	−0.12	0.07
Number of medications	−0.19*	−0.39	0.00	−0.09	−0.37	0.19	−0.03	−0.28	0.22
Number of medical conditions				−0.43	−0.96	0.11	−0.22	−0.70	0.27
CCI				0.48*	0.20	0.76	−0.02	−0.30	0.26
Age							0.13*	0.09	0.17
aR^2	0.04			0.08			0.25

Notes: Model I: Medication-related factors (number of medications, MRCI, DBI); Model II: adjusted for disease burden factors (CCI, number of medical conditions); Model III: adjusted for demographic factor (age); R², regression coefficient; aR², adjusted R² (ie, the proportion of variance in the MRB-QoL domains explained by independent variables included in the regression models adjusted by the rest of the covariates); bold values denote aR²; β, regression coefficients (the change in the MRB-QoL domain in relation to the independent variables in the model adjusted by the rest of the covariates). *Indicates variables with significant (pl<0.05) association with MRB-QoL domains.

Abbreviations: CCI, Charlson Comorbidity Index; CI, confidence Interval; DBI, Drug Burden Index; MRB-QoL, Medication-Related Burden Quality of Life; MRCI, Medication Regimen Complexity Index.