Thiazolidinediones are associated with a reduced risk of COPD exacerbations

Figures & data

Figure 1 Cohort selection.

Abbreviations: COPD, chronic obstructive pulmonary disease; TZD, thiazolidinedione.

Table 1 Baseline characteristics of TZD and non-TZD patients

Characteristic	TZD	Non-TZD
Number of patients (n)	7,887	42,347
Age (SD)*	68.6 (9.0)	69.2 (9.4)
Female (%)	1.5	1.7
Married (%)*	64.5	61.1
Race: white (%)*	76.2	79.8
Free care
Due to disability (%)*	39.3	37.6
Due to low income (%)*	13.2	14.5
Number of baseline primary care visits (SD)*	6.9 (7.7)	6.5 (5.6)
Distance to the VA (miles) (SD)	28.1 (31.2)	27.6 (32.0)
Diagnostic Cost Group score (SD)*	1.5 (0.8)	1.4 (0.8)
Diabetes Severity Index (SD)*	2.0 (1.8)	1.8 (1.7)
Baseline number of exacerbations (SD)*	0.17 (0.78)	0.23 (1.1)
Comorbidities in prior year
Asthma (%)	8.8	9.3
Atrial fibrillation/flutter (%)*	9.3	12.2
Congestive heart failure (%)*	13.1	14.5
Ischemic heart disease (%)*	33.1	31.8
Alcohol abuse (%)*	1.9	3.1
Other drug abuse (%)*	15.7	17.4
Schizophrenia (%)*	1.6	2.2
Depression (%)	12.4	12.3
Concurrent therapy
Inhaled corticosteroid (%)*	29.6	33.1
Inhaled long-acting beta agonist (%)*	28.2	29.9
Inhaled tiotropium (%)*	3.7	4.4
Nebulized beta agonist/ipratropium (%)*	18.3	20.8
No of short-acting beta agonist canisters (SD)*	5.8 (7.0)	6.1 (7.0)
No of ipratropium canisters (SD)	4.3 (6.0)	4.4 (6.2)
Any diuretic therapy (%)	56.3	55.0

Notes:

* P<0.05.

Abbreviations: TZD, thiazolidinedione; SD, standard deviation; VA, Veterans Affairs.

Table 2 Risk of COPD exacerbation with exposure to TZDs

Event	Exposure	Mean (SD)	Regression	IRR	95% CI
Outpatient exacerbation	TZD	0.22 (0.68)	Unadjusted	0.79	0.74–0.85
	Non-TZD	0.28 (0.84)	Model 1*	0.78	0.73–0.83
			Model 2†	0.85	0.80–0.91
Inpatient exacerbation	TZD	0.03 (0.23)	Unadjusted	0.70	0.58–0.84
	Non-TZD	0.04 (0.27)	Model 1*	0.69	0.57–0.82
			Model 2†	0.81	0.68–0.97
Outpatient or inpatient	TZD	0.25 (0.76)	Unadjusted	0.77	0.73–0.83
exacerbation	Non-TZD	0.32 (0.95)	Model 1*	0.77	0.72–0.82
			Model 2†	0.85	0.80–0.91

Notes:

* Adjusted for age, sex, marital status, race, free care, distance to VA facility, number of primary care encounters, Diagnostic Cost Group score, Diabetes Severity Index score, asthma, atrial fibrillation, heart failure, ischemic heart disease, alcohol abuse, drug abuse, schizophrenia, depression, and diuretic medications.

† Adjusted for above variables as well as baseline year exacerbations and respiratory medication prescriptions.

Abbreviations: COPD, chronic obstructive pulmonary disease; TZDs, thiazolidinediones; IRR, incidence rate ratio; CI, confidence interval; VA, Veterans Affairs.

Table 3 Risk for mortality with exposure to TZD

Event	Exposure	Number of patients (%)	Regression	OR	95% CI
Mortality	TZD	452 (5.7)	Unadjusted	0.90	0.81–0.99
	Non-TZD	2,684 (6.3)	Model 1*	0.92	0.83–1.03
			Model 2†	0.90	0.81–1.00

Notes:

* Adjusted for age, sex, marital status, race, free care, distance to VA facility, number of primary care encounters, Diagnostic Cost Group score, Diabetes Severity Index score, asthma, atrial fibrillation, heart failure, ischemic heart disease, alcohol abuse, drug abuse, schizophrenia, depression, and diuretic medications.

† Adjusted for above variables as well as baseline year exacerbations and respiratory medication prescriptions.

Abbreviations: TZD, thiazolidinedione; OR, odds ratio; CI, confidence interval.