Prompt initiation of maintenance treatment following a COPD exacerbation: outcomes in a large insured population

Figures & data

Figure 1 Study design.

Notes: ^aDischarge date after the first chronologically occurring COPD exacerbation resulting in hospitalization or an ED visit.
Abbreviations: ED, emergency department; MT, maintenance treatment.

Table 1 Baseline demographics and characteristics

Demographic characteristics	Total (N=6,521)	Prompt MT (n=4,555)	Delayed MT (n=1,966)	P-valuea
Age, mean (SD) years	67.4 (12.0)	66.9 (11.8)	68.4 (12.2)	<0.001
Age category, n (%)
40–64 years	3,035 (46.5)	2,203 (48.4)	832 (42.3)	<0.001
≥65 years	3,486 (53.5)	2,352 (51.6)	1,134 (57.7)
Female, n (%)	3,595 (55.1)	2,526 (55.5)	1,069 (54.4)	0.421
Region, n (%)
Northeast	1,159 (17.8)	853 (18.7)	306 (15.6)	<0.001
North central	2,633 (40.4)	1,839 (40.4)	794 (40.4)
South	2,089 (32.0)	1,441 (31.6)	648 (33.0)
West	555 (8.5)	356 (7.8)	199 (10.1)
Unknown	85 (1.3)	66 (1.4)	19 (1.0)
Comorbidity in the pre-index period
CCIb, mean (SD)	0.65 (1.2)	0.66 (1.2)	0.64 (1.1)	0.600
Number of unique prescription classes, mean (SD)	9.4 (6.2)	9.2 (6.0)	9.9 (6.5)	<0.001
Number of unique diagnosesc, mean (SD)	9.4 (7.7)	9.0 (7.5)	10.2 (8.1)	<0.001
Specific comorbidities, n (%)
Asthma	896 (13.7)	562 (12.3)	334 (17.0)	<0.001
Depression	840 (12.9)	532 (11.7)	308 (15.7)	<0.001
URTI	1,236 (19.4)	876 (19.2)	387 (19.7)	0.671
LRTI	2,443 (37.5)	1,640 (36.0)	803 (40.8)	<0.001
CVD	3,325 (51.0)	2,275 (49.9)	1,050 (53.4)	0.010
Proxies for COPD severity in pre-index period
Inhaled SAMA use, n (%)	956 (14.7)	590 (13.0)	366 (18.6)	<0.001
SABA canister use, n (%)	2,160 (33.1)	1,468 (32.2)	692 (35.2)	0.019
OCS prescription use, n (%)	2,222 (34.1)	1,490 (32.7)	732 (37.2)	<0.001
Antibiotic use, n (%)	4,068 (62.4)	2,825 (62.0)	1,243 (63.2)	0.357
Home oxygen therapy use, n (%)	556 (8.5)	333 (7.3)	223 (11.3)	<0.001
Mechanical ventilation/intubation during any hospital/ED visit, n (%)	36 (0.6)	23 (0.5)	13 (0.7)	0.434
Any COPD exacerbation, n (%)	809 (12.4)	499 (11.0)	310 (15.8)	<0.001
COPD-related total costs, mean (SD)	US$576 (US$2,912)	US$457 (US$2,186)	US$852 (US$4,118)	<0.001
Index exacerbation typed, n (%)
Hospitalization	3,370 (51.7)	2,594 (56.9)	776 (39.5)	<0.001
ED	3,151 (48.3)	1,961 (43.1)	1,190 (60.5)
Index exacerbation diagnosisd, n (%)
Emphysema (492.xx)	119 (1.8)	85 (1.9)	34 (1.7)	<0.001
Chronic bronchitis (491.xx)	5,881 (90.2)	4,144 (91.0)	1,737 (88.4)
Chronic airway obstruction (496.xx)	521 (8.0)	326 (7.2)	195 (9.9)

Notes:

a Values in bold are statistically significant (Student’s t-test for continuous and chi-square for categorical variables).

b COPD, asthma, and cardiovascular disease were excluded from the CCI.

c A unique count of disease states beyond those used to calculate the CCI and specific comorbidities is listed.

d These were the only index exacerbation characteristics (excluding maintenance medication prescribed) with a significant difference between the prompt and delayed MT cohorts; index year (P=0.231) and season of index date (P=0.109) were not significantly different between the two MT cohorts.

Abbreviations: CCI, Charlson Comorbidity Index; CVD, cardiovascular disease; ED, emergency department; LRTI, lower respiratory tract infection; MT, maintenance treatment; OCS, oral corticosteroids; SABA, short-acting β₂ agonist; SAMA, short-acting anti-muscarinic agent; SD, standard deviation; URTI, upper respiratory tract infection.

Figure 2 Adjusted annual costs per patient according to MT initiation cohort (prompt =0–30 days; delayed =31–180 days).

Notes: *P<0.010. Adjusted costs obtained from statistical model: semilog OLS controlling for age, sex, region, comorbidity, COPD severity (including pre-index COPD-related total costs), and type of index exacerbation. A two-part semilog OLS model was used for medical costs.
Abbreviations: CI, confidence interval; MT, maintenance treatment; OLS, ordinary least squares.

Figure 3 (A) Adjusted relative odds of subsequent COPD exacerbation and (B) adjusted relative exacerbation incident rate ratio for the delayed MT cohort (prompt =0–30 days; delayed =31–180 days).

Notes: *P<0.050; **P<0.010; ***P<0.001. Dashed lines at 1.00 indicate the reference lines. Relative odds obtained from logistic regression model estimating likelihood of an event controlling for index exacerbation type and baseline covariates. Incidence rate ratio obtained from zero-inflated negative binomial regression model estimating likelihood of an event controlling for index exacerbation type and baseline covariates.
Abbreviations: CI, confidence interval; ED, emergency department; MT, maintenance treatment; OCSs, oral corticosteroids; Phy + Rx, physician visit with a prescription for OCSs and/or antibiotics in the subsequent 5 days.

Figure 4 Adjusted annual cost per patient by medical component (prompt =0–30 days; delayed =31–180 days).

Notes: *P<0.050. Adjusted costs obtained from statistical model: a two-part generalized linear model controlling for age, sex, region, comorbidity, COPD severity (including pre-index COPD-related total costs), and type of index exacerbation.
Abbreviation: ED, emergency department.