Adherence to Long-Acting Inhaled Therapies among Patients with Chronic Obstructive Pulmonary Disease (COPD)

Figures & data

Table 1.  Patient characteristics based upon adherence status

	Long-Acting Beta Agonists		Inhaled Corticosteroids
	Non-Adherent (N = 77)	Adherent (N = 90)	Non-Adherent (N = 110)	Adherent (N = 74)
Baseline Characteristics
Mean age (yrs) (SD)	68.1 (10.4)	70.9 (9.9)	68.3 (11.4)	69.9 (9.1)
Male (N) (%)	76 (99)	87 (97)	105 (95)	74 (100)
Education (N) (%)
Less than high school	16 (21)	8 (9)	17 (15)	8 (11)
High school grad +/- some college	44 (57)	50 (56)	65 (59)	43 (58)
College grad +/- some graduate school	12 (16)	23 (26)	21 (19)	16 (22)
Marital Status (N) (%)
Single/never married	3 (4)	3 (3)	7 (6)	2 (3)
Married	32 (42)	47 (52)	45 (41)	38 (51)
Divorced/separated	29 (38)	19 (21)	33 (30)	14 (19)
Widowed	8 (10)	12 (13)	18 (16)	13 (18)
Race (N) (%)
White	58 (75)	72 (80)	84 (76)	59 (80)
Black	8 (10)	3 (3)	11 (10)	5 (7)
Other	6 (8)	4 (4)	7 (6)	2 (3)
Annual Income (N) (%)
< $20,000	26 (34)	32 (36)	43 (39)	23 (31)
$20,000–39,999	28 (36)	25 (28)	33 (30)	23 (31)
≥ 40,000	14 (18)	19 (21)	21 (19)	16 (22)
Mean SIC score (SD)*	8.9 (3.0)	9.1 (2.9)	8.7 (2.8)	8.5 (2.7)
Mean FEV1% predicted (SD)	47.4 (21.9)	45.3 (21.0)	50.1 (21.7)	46.2 (18.6)
Complexity of Medication Regimen
Mean number of total inhaled medications (SD)	3.47 (0.64)	3.59 (0.62)	3.31 (0.79)	3.64 (0.56)
Mean number of oral medications (SD)	2.58 (1.87)	2.54 (1.64)	2.65 (1.77)	2.96 (1.72)
Health Behaviors
Audit-C score (N) (%)
0	40 (52)	38 (42)	47 (43)	33 (45)
1–4	24 (31)	42 (47)	50 (45)	30 (41)
5–12	13 (17)	6 (7)	11 (10)	8 (11)
Smoking Status (N) (%)
Former/Never Smoker	43 (56)	69 (77)	78 (71)	57 (77)
Current Smoker	29 (38)	12 (13)	23 (21)	10 (14)
Confidence in self-management of breathing problems (N) (%)
Never-some of the time	19 (25)	7 (8)	18 (16)	11 (15)
A good bit-most of the time	40 (52)	52 (58)	68 (62)	36 (49)
All of the time	16 (21)	28 (31)	23 (21)	25 (34)
Perception of provider skill/knowledge in lung disease (N) (%)
Not at all-somewhat knowledgeable	17 (22)	4 (4)	15 (14)	5 (7)
Quite knowledgeable	18 (23)	14 (16)	27 (25)	17 (23)
Very knowledgeable	16 (21)	32 (36)	31 (28)	21 (28)
Expert	14 (18)	31 (34)	15 (14)	24 (32)

Column totals may not sum to 100% due to missing values; values in bold with p-value < 0.05.

* Number of subjects differs for SIC due to missing values: LABA: Non-adherent (N = 72), Adherent (N = 81); ICS: Non-adherent (N = 101), Adherent (N = 66).

Table 2.  Associations of patient characteristics and health behaviors with adherence status

	Long-Acting Beta Agonists		Inhaled Corticosteroids
	Odds Ratio (95%CI)	P-value	Odds Ratio (95%CI)	P-value
Characteristics and Medication Regimen
Age (per year)	1.07 (1.00, 1.15)	0.045	1.03 (0.97, 1.08)	0.326
Education
Less than high school	1.00	Referent	1.00	Referent
High school grad +/- some college	4.76 (1.41, 16.09)	0.012	1.28 (0.36, 4.51)	0.701
College grad +/- graduate school	7.77 (1.63, 37.15)	0.010	1.49 (0.34, 6.54)	0.598
Marital Status
Single/never married	1.00	Referent	1.00	Referent
Married	1.84 (0.27, 12.73)	0.535	4.55 (0.73, 28.46)	0.105
Divorced/separated	0.71 (0.12, 4.24)	0.710	1.34 (0.26, 6.91)	0.727
Widowed	1.36 (0.16, 11.50)	0.777	4.40 (0.66, 29.43)	0.126
Race
White	1.00	Referent	1.00	Referent
Black	0.13 (0.02, 0.71)	0.018	0.46 (0.15, 1.32)	0.145
Other	0.58 (0.15, 2.31)	0.439	0.38 (0.06, 2.44)	0.306
Annual Income
< $20,000	1.00	Referent	1.00	Referent
$20,000–39,999	0.46 (0.15, 1.36)	0.161	0.96 (0.39, 2.38)	0.938
≥ 40,000	0.79 (0.27, 2.31)	0.663	0.90 (0.30, 2.67)	0.853
SIC (per one unit increase)	0.90 (0.69, 1.17)	0.420	0.83 (0.63, 1.09)	0.173
FEV1% predicted (per 10% increase)	0.86 (0.74, 1.00)	0.044	0.87 (0.71, 1.06)	0.164
Total number of inhaled medications	1.25 (0.66, 2.38)	0.489	1.80 (0.98, 3.30)	0.059
Number of oral medications	0.98 (0.78, 1.22)	0.825	1.19 (0.92, 1.54)	0.174
Health Behaviors*
Audit-C score
0	1.00	Referent	1.00	Referent
1–4	1.72 (0.74, 3.98)	0.207	0.56 (0.23, 1.36)	0.203
5–12	0.59 (0.14, 2.49)	0.472	0.81 (0.22, 2.94)	0.745
Smoking Status
Former/Never Smoker	1.00	Referent	1.00	Referent
Current Smoker	0.32 (0.11, 0.97)	0.043	0.48 (0.17, 1.36)	0.167

Odds of adherence to each medication estimated using multiple logistic regression clustered by clinician and using robust standard errors. Values in bold indicate p-value < 0.05. *Adjusted for Age, Education, Marital Status, Race, Income, SIC score (with exclusion of smoking), FEV1% predicted, and complexity of medication regimen.

Table 3.  Associations of patient perceptions with adherence status

	Long-Acting Beta Agonists		Inhaled Corticosteroids
	Odds Ratio (95%CI)	P-value	Odds Ratio (95%CI)	P-value
Self-Efficacy*
Confidence in self-management of breathing problems
Never-some of the time	1.00	Referent†	1.00	Referent†
A good bit-most of the time	3.57 (1.09, 11.71)	0.036	0.69 (0.23, 2.07)	0.508
All of the time	5.92 (1.86, 18.85)	0.003	1.58 (0.47, 5.28)	0.461
Confidence in Provider*
Perception of provider skill/knowledge
Not at all-somewhat knowledgeable	1.00	Referent‡	1.00	Referent‡
Quite knowledgeable	4.21 (1.27, 13.93)	0.019	3.03 (0.67, 13.61)	0.149
Very knowledgeable	15.28 (4.25, 54.97)	< 0.001	2.62 (0.58, 11.94)	0.213
Expert	21.70 (6.79, 69.37)	< 0.001	7.93 (1.71, 36.67)	0.008

Odds of adherence to each medication estimated using multiple logistic regression clustered by clinician and using robust standard errors. *Adjusted for Age, Education, Marital Status, Race, Income, SIC score. FEV1% predicted, and complexity of medication regimen; Values in bold indicate p-value < 0.05. †p-value for grouped linear trend = 0.003 for LABA and 0.240 for ICS; ‡ p-value for grouped linear trend = < 0.001 for LABA and 0.007 for ICS.

Table

Table e1: Wording of Questions about Patient Perceptions and Response Choices
Question 1: During the past 4 weeks, how often did you feel confident dealing with your breathing problems?
Responses(N = 367)	#of Subjects Responding (N,%)	Combined Category for Analysis	# Respondents in Each Category for Analysis
1) Never	4 (1%)	1) Never-Some of the time	68 (18%)
2) Almost Never	6 (2%)
3) A little of the time	13 (3%)
4) Some of the time	45 (12%)
5) A good bit of the time	44 (12%)	2) A good bit- most of the time	193 (53%)
6) Most of the time	149 (41%)
7) All of the time	106 (29%)	3) All of the time	106 (29%)
Question 2: How skilled and knowledgeable is ______ about diagnosing and treating your lung disease? (blank filled in with clinician identified as patient as primary provider for lung disease)
Responses(N = 305)	#of Subjects Responding (N,%)	Combined Category for Analysis	# Respondents in Each Category for Analysis
1) Not at all knowledgeable	1 (1%)	1) Not at all- somewhat knowledgeable	46 (16%)
2) Somewhat knowledgeable	45 (15%)
3) Quite knowledgeable	92 (30%)	2) Quite knowledgeable	92 (30%)
4) Very knowledgeable	96 (31%)	3) Very knowledgeable	96 (31%)
5) Extremely knowledgeable, an expert	71 (23%)	4) Extremely knowledgeable, an expert	71 (23%)