The Identification and Cost of Acute Chronic Obstructive Pulmonary Disease Exacerbations in a United States Population Healthcare Claims Database

Figures & data

Table 1. Demographic and disease characteristics of patients in the claims sample.

Characteristics	Recorded exacerbations identified by the final algorithm (n = 149,607)		No recorded exacerbations identified by the final algorithm (n = 94,391)
Mean age, years (SD)	67.6 (11.4)		68.6 (11.2)
Age, years, n (%)
40–54	22,321 (14.9)		11,969 (12.7)
55–64	36,686 (24.5)		21,173 (22.4)
65–74	44,439 (29.7)		29,423 (31.2)
≥75	46,161 (30.9)		31,826 (33.7)
Male, n (%)	67,730 (45.3)		47,870 (50.7)
Insurance type, n (%)
Commercial	70,498 (47.1)		42,537 (45.1)
Medicare Advantage	79,109 (52.9)		51,854 (54.9)
Most common baseline comorbidities,* n (%)
Hypertension	103,441 (69.1)		64,731 (68.6)
Lipid metabolism disorders	88,743 (59.3)		57,381 (60.8)
Heart disease	85,565 (57.2)		51,261 (54.3)
Other lower respiratory disease	86,099 (57.6)		49,095 (52.0)
Respiratory infections	72,145 (48.2)		32,727 (34.7)
Non-traumatic joint disorders	65,805 (44.0)		36,746 (38.9)
Other connective tissue disease	63,976 (42.8)		35,023 (37.1)
Eye disorders	60,087 (40.2)		38,708 (41.0)
Diseases of the urinary system	58,400 (39.0)		34,185 (36.2)
COPD and other COPD-related diagnoses^†	54,183 (36.2)		32,301 (34.2)
Asthma	15,051 (10.1)		7,281 (7.7)
Follow-up clinical characteristics
Mean COPD severity score, starting algorithm (SD)	31.1 (12.8)		24.4 (7.0)
Oxygen use, n (%)	30,767 (20.6)		12,048 (12.8)
Spirometry use, n (%)	51,039 (34.1)		27,342 (29.0)
Pulmonologist visits, n (%)	62,122 (41.5)		25,666 (27.2)
Mean pulmonologist visit count (SD)	2.4 (6.0)		0.9 (2.7)
Mean pulmonologist visit count^‡ (SD)	5.9 (8.1)		3.3 (4.3)
Medication use during the study period, n (%)
Antibiotics	127,645 (85.3)		42,510 (45.0)
Systemic corticosteroids	93,791 (62.7)		21,360 (22.6)
SABA	67,527 (45.1)		21,650 (22.9)
ICS/LABA	42,396 (28.3)		14,881 (15.8)
Anticholinergic/SABA	29,190 (19.5)		8,565 (9.1)
Anticholinergic (maintenance)	27,571 (18.4)		11,471 (12.2)
ICS	13,893 (9.3)		4,704 (5.0)
Anticholinergics	8,856 (5.9)		2,263 (2.4)
LABA	3,701 (2.5)		1,304 (1.4)
Methylxanthines	4,495 (3.0)		1,512 (1.6)
PDE/roflumilast	159 (0.1)		35 (0.0)

*Defined using clinical classifications software managed by the AHRQ.

^†Index date defined as earliest claim with ICD-9-CM diagnosis code 491, 492, or 496 during identification period. Baseline evidence of COPD via diagnosis codes was sparse by definition, as they were baseline claims that occurred prior to the identification period. AHRQ also included ICD-9-CM diagnosis codes 490, 494, 494.0, and 494.1.

^‡Among those with a pulmonologist visit: claims recorded group n = 62,122; no claims group n = 25,666.

Abbreviations: AHRQ = Agency for Healthcare Research and Quality; COPD = chronic obstructive pulmonary disease; ICD = International Classification of Diseases (Ninth Revision, Clinical Modification); ICS = inhaled corticosteroids; LABA = long-acting β₂-agonist; PDE = phosphodiesterase 4 inhibitor; SABA = short-acting β₂-agonist; SD = standard deviation.

Figure 1. Patient disposition flow chart.

Data from inpatient/ER (secondary care) charts, were requested only if the primary care chart had insufficient data.

Abbreviations: ER = emergency room.

Table 2. Healthcare costs for the chart population predicted by the initial and final algorithms.

Chart data		Initial algorithm (n = 402)	Initial algorithm: unobserved episodes (n = 402)*	Final algorithm (n = 402)	Final algorithm: unobserved episodes (n = 402)*
Total costs of all patients’ AECOPD episodes, USD, including all patients in the chart population	Valid n	402	402	402	402
	Mean per patient (SD)	9,911 (24,508)	287 (1,136)	9,623 (24,216)	252 (976)
	Sum	3,984,157	115,529	3,868,623	101,480
Average cost during each patient’s AECOPD episode, USD, including only patients with at least one AECOPD episode	Valid n	302	122	301	122
	Mean per patient (SD)	6,883 (18,145)	707 (1,586)	6,760 (18,158)	607 (1,261)
	Sum	2,078,622	86,293	2,034,877	74,108

Costs were adjusted using the annual medical care component of the Consumer Price Index, 2017, and were measured not just for individual events, but for the entire episode, which could contain combinations of moderate and severe (hospitalization) events. For example, the patient could have visited the ER and received an antibiotic prescription, and then a week later entered the hospital and that would have been counted as a single episode.

*All costs incurred during unobserved episodes in the follow-up year, but only using claims that were not already used in exacerbation episodes. Of the 402 patients included, 100 had no claims-identified AECOPD episodes per the initial algorithm.

Abbreviations: AECOPD = acute exacerbation of chronic obstructive pulmonary disease; SD = standard deviation; USD = US dollars.

Table 3. Exacerbation costs for the final algorithm from the multivariate analysis two-part model, including predicted costs and bootstrapped 95% confidence intervals.

Exacerbation costs (final algorithm)		Unobserved			False-positive			Total (true-positive + false-positive + unobserved)
	n	Mean	Lower	Upper	Mean	Lower	Upper	Mean	Lower	Upper
			95% CI	95% CI		95% CI	95% CI		95% CI	95% CI
Observed – per patient
Chart	402	252	157	348	6,087	4,023	8,150	9,876	7,491	12,260
Predicted – per patient
Chart	402	273	193	432	6,168	4,297	8,490	10,139	7,989	13,554
Claims	243,998	358	212	710	6,727	3,608	12,882	11,191	9,135	16,664
Predicted – population total
Claims population scaled to 100,000	100,000	35,761,731	21,191,692	70,958,918	672,735,492	360,794,919	1,288,199,800	1,119,098,679	913,536,973	1,666,357,995

Costs were adjusted using the annual medical care component of the Consumer Price Index, 2017.

Abbreviations: CI = confidence interval.

Data availability statement

The data contained in our database contains proprietary elements owned by Optum and, therefore, cannot be broadly disclosed or made publicly available at this time. The disclosure of these data to third-party clients assumes certain data security and privacy protocols are in place, and that the third-party client has executed our standard license agreement which includes restrictive covenants governing the use of the data.