Cardiac Troponin-I Predicts Long-Term Mortality in Chronic Obstructive Pulmonary Disease

Figures & data

Table 1 Demographic and clinical characteristics of sub-groups of patients with and without cardiac troponin I (cTnI) measurement

Patient Characteristics	cTnI measured (n = 182)	cTnI not measured (n = 953)	p-Value
Age, mean ± SD (years)	71.2 ± 10.5	72.1 ± 9.8	NS
Gender (male/female)	135/47	625/328	NS
Current smoker, n (%)	94 (52.0%)	457 (48.1%)	NS
FEV1 (% of predicted)	56 ± 3.3	52 ± 2.4	NS
Ischemic heart disease, n (%)	120 (52.7%)	486 (51.6%)	NS
Congestive heart failure, n (%)	21 (11.5%)	125 (13.1%)	NS
Diabetes mellitus, n (%)	47 (26.3%)	237 (24.8%)	NS
Chronic renal failure, n (%)	0 (0%)	24 (2.5%)	0.022
Atrial fibrillation, n (%)	47 (25.8%)	219 (22.9%)	NS
PaCO2, mean ± SD (mmHg)	47.7 ± 13.4	51.2 ± 16.7	NS
PaO2, mean ± SD (mmHg)	54.9 ± 32.1	51.3 ± 21.2	NS
Hospital stay, mean ± SD (days)	8.4 ± 8.6	7.7 ± 5.2	NS
Re-admissions for AECOPD (n, range)	1.6 (1–18)	1.5 (1–17)	NS
Follow-up, mean ± SD, Median (range), months	50.1 ± 45.6, 35 (3–83)	52.3 ± 38.6, 32 (2–76)	NS

Figure 1 Survival of patients according to cTnI level.

Table 2 Comparison of data between survivors and non-survivors

Patients Characteristics	Alive (n = 116)	Dead (n = 66)	p-Value
Age: mean ± SD (years)	70.4 ± 11.2	72.5 ± 9.0	0.198
above 60 (years)	99 (85.3%)	62 (93.9%)	0.132
Gender (male/female)	85/31	50/16	0.848
Current Smoker, n (%)	61 (52.5%)	27 (40.9%)	0.164
FEV1 (% of predicted)	53 ± 11.1	52 ± 14.8	0.603
Ischemic heart disease, n (%)	51 (43.9%)	45 (68.1%)	0.0028
Congestive heart failure, n (%)	12 (10.3%)	9 (13.6%)	0.6300
Diabetes mellitus, n (%)	29 (25%)	19 (28.7%)	0.702
Chronic renal failure, n (%)	0 (0%)	24 (2.5%)	0.022
Atrial fibrillation, n (%)	25 (21.5%)	23 (34.8%)	0.113
PaCO2, mean ± SD (mmHg)	53.3 ± 18.0	60.3 ± 22.1	0.024
PaO2, mean ± SD (mmHg)	57.8 ± 36.1	50.1 ± 23.5	0.317
cTnI, mean ± SD (μ g· L^−1)	0.53 ± 2.08	1.35 ± 3.17	0.0033
> 0.03 μ g· L^−1	58 (50%)	50 (75.7%)	0.0087
Follow-up period, mean ± SD (months)	59.2 ± 46.2	34.0 ± 40.1	0.0003

Figure 2 Receiver operator curve for predictive value of cardiac-specific troponin I for mortality following COPD exacerbation.

Table 3 Comparison of clinical and physiological parameters between patients with cTnI levels ≤ 0.03 μ g· L⁻¹ or > 0.03 μ g· L⁻¹

Patient Characteristics	cTnI Levels ≤ 0.03 μ g· L^−1 (n = 99)	cTnI Levels > 0.03 μ g· L^−1 (n = 83)	p Value
Age, mean ± SD (years)	71.6 ± 11.1	70.6 ± 9.9	NS
FEV1 (% of predicted)	52 ± 10.3	51 ± 12.1	NS
Ischemic heart disease, n (%)	48 (43.9%)	45 (68.1%)	NS
Diabetes mellitus, n (%)	23 (25%)	24 (28.7%)	NS
Atrial fibrillation, n (%)	24 (21.5%)	16 (34.8%)	NS
PaCO2, mean ± SD (mmHg)	53.0 ± 18.6	58.0 ± 21.4	0.0469
PaO2, mean ± SD (mmHg)	59.7 ± 39.5	51.2 ± 23.4	NS
cTnI, mean ± SD (μ g· L^−1)	0.253 ± 1.58	1.51 ± 3.24	< 0.0001

Figure 3 Survival of patients stratified according to cTnI levels above and below 0.03 μg·L−1.

Table 4 Risk factors and associated unadjusted hazard ratios for mortality probability using the Cox proportional-hazards model

Variable	Hazard Ratio	95% Confidence Interval	p-Value
Age (yr)	1.0208	0.9973–1.0448	0.0854
Age > 60	2.7864	1.0168–7.6358	0.0474
PaCO2	1.0123	0.9932–1.0248	0.0506
Ischemic heart disease	2.5190	1.4901–4.2584	0.0006
cTnI	1.0653	0.9920–1.1441	0.0006

Table 5 Risk factors and associated adjusted hazard ratios for mortality probability using multivariate analysis

	Multiple Cox Regression Analysis
Variables	Hazard Ratio	95% Confidence Interval	p-Value
Age > 60	1.3421	0.9851–1.0248	0.0681
Ischemic heart disease	2.3350	1.3796–3.9520	0.0017
cTnI	1.31541	1.0753–2.2512	0.2513