Association between hemoglobin and prognosis in patients admitted to hospital for COPD

Figures & data

Table 1 Characteristics of patients admitted for the first time to hospitals for acute exacerbations of COPD

Characteristics	Anemia at admission		Normal hemoglobin at admission		Polycythemia at admission		All patients
	Died in hospital	Discharged	Died in hospital	Discharged	Died in hospital	Discharged
	n=249	n=1,903	n=217	n=3,996	n=42	n=562	n=6,969
Male	148 (59.4%)	1,109 (58.3%)	98 (45.2%)	1,772 (44.3%)	7 (16.7%)	78 (13.9%)	3,212 (46.1%)
Age (years), median (IQR)	79 (72.6–84.8)	77.8 (69.8–83.6)	80.2 (75.5–84.3)	72.7 (63.5–79.7)	76.2 (72–82.2)	70.1 (61.6–76.9)	74.7 (65.4–81.2)
Laboratory test results
First hemoglobin, median (IQR)	109.6 (99.9–117.6)	114.4 (106.3–119.2)	137 (130.5–145)	138.6 (132.1–146.6)	159.5 (155.1–169.2)	157.9 (154.7–167.6)	133.7 (120.9–145)
Lowest eGFR, median (IQR)*	39 (23.8–66.2)	60 (40–81)	48 (28–70)	72 (54–91)	55 (33.2–69.8)	73 (55–93)	68 (48–89)
Medication
Medication for obstructive airway diseases	144 (57.8%)	1,324 (69.6%)	147 (67.7%)	2,888 (72.3%)	27 (64.3%)	406 (72.2%)	4,936 (70.8%)
Antidiabetics	37 (14.9%)	250 (13.1%)	32 (14.7%)	370 (9.3%)	1 (2.4%)	37 (6.6%)	727 (10.4%)
ACE inhibitors and angiotensin II receptor blockers	100 (40.2%)	810 (42.6%)	60 (27.6%)	1,316 (32.9%)	10 (23.8%)	162 (28.8%)	2,458 (35.3%)
Antithrombotics	138 (55.4%)	1,080 (56.8%)	109 (50.2%)	1,609 (40.3%)	15 (35.7%)	187 (33.3%)	3,138 (45%)
Comorbidity
Cancer	65 (26.1%)	277 (14.6%)	28 (12.9%)	301 (7.5%)	7 (16.7%)	26 (4.6%)	704 (10.1%)
AMI	59 (23.7%)	392 (20.6%)	49 (22.6%)	554 (13.9%)	6 (14.3%)	56 (10%)	1,116 (16.0%)
Heart failure	59 (23.7%)	367 (19.3%)	37 (17.1%)	383 (9.6%)	3 (7.1%)	51 (9.1%)	900 (12.9%)
Charlson Comorbidity Score, median (IQR)	3 (2–4)	2 (1–3)	2 (1–3)	1 (1–2)	1 (1–2.8)	1 (1–2)	2 (1–3)
Admissions within the preceding 2 years
Admissions, median (IQR)	2 (1–4)	2 (1–4)	2 (1–3)	1 (1–2)	1 (1–2)	1 (1–2)	2 (1–3)

Notes:

* n_total=6,950. Anemia: males, hemoglobin <130 g/L; females, hemoglobin <120 g/L. Polycythemia: males, hemoglobin >170 g/L; females, hemoglobin >150 g/L.

Abbreviations: IQR, interquartile range; eGFR, estimated glomerular filtration rate; ACE, angiotensin converting enzyme; AMI, acute myocardial infarction.

Table 2 Comparison with reported frequencies of anemia in AECOPD in literature

Reference	Male:female ratio	Patients	Definition of anemia	Prevalence in study	Prevalence in present population
Martinez-Rivera et al^Citation19	109:8	Patients admitted to wards for AECOPD without some severe diseases	Male and female: <130 g/L	33%	39%
Silverberg et al^Citation31	33:27	Patients admitted for AECOPD	Male and female: <120 g/L	44%	24%
Mydin et al^Citation18	29:36	Patients admitted for AECOPD and treated with noninvasive mechanical ventilation	Male: <130 g/L and female:<115 g/L	42%	27%
Rasmussen et al^Citation32	100:122	Patients admitted to ICU for AECOPD and treated with invasive mechanical ventilation	Male and female: <120 g/L	18%	24%

Note: Prevalence in present population reported after standardization of the male:female ratios and anemia definitions.

Abbreviations: AECOPD, acute exacerbation of COPD; ICU, intensive care unit.

Figure 1 Distribution of concentrations of hemoglobin (Hb), measured after admission for all first-time admitted patients.

Note: Dotted lines indicate World Health Organization lower limits.

Figure 2 Risk of death after discharge for patients discharged alive, by concentration of hemoglobin.

Notes: Measurements rounded to nearest 10 g/L. (A) Unadjusted; (B) adjusted for age, use of antidiabetics, use of ACE and/or AT₂R inhibitors, use of antithrombotics, quartile of lowest eGFR, cancer, heart failure, and AMI. Only patients with measurements of both hemoglobin and eGFR were included.
Abbreviations: eGFR, estimated glomerular filtration rate; AMI, acute myocardial infarction; HR, hazard ratio; CI, confidence interval.

Figure 3 Survival curves for patients discharged alive, by sex and level of hemoglobin.

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SilverbergDSMorRWeuMTSchwartzDSchwartzIFCherninGAnemia and iron deficiency in COPD patients: prevalence and the effects of correction of the anemia with erythropoiesis stimulating agents and intravenous ironBMC Pulm Med2014142424564844

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