Risk Factors Analysis for Hemoglobin Decline Caused by Diagnostic Blood Collection in Respiratory Department in North China: A Case-Control Study

Figures & data

Figure 1 The process of data collection, screening, grouping, and analysis.

Table 1 Baseline Characteristics and Data of the Patients

Variables	Group 1	Group2	P value
	Significantly Hemoglobin Decline (n=234)	Non-Significantly Hemoglobin Decline (n=296)
Age, y	66.34±16.443	63.06±18.774	0.093
Male, %	62.4	54.7	0.076
Height, cm	164.4±8.293	164.77±8.858	0.753
Weight, kg	66.92±14.843	67.38±15.751	0.891
BMI, kg/m2	24.75±5.203	24.89±5.826	0.902
Blood Collection Volume, mL	67.53±26.977	57.4±19.169	<0.001
Length of stay, d	9.96±3.755	8.55±2.986	<0.001
Blood Collection Volume/d, mL	7.217±2.722	7.211±2.836	0.728
Hb at Admission, g/L	139.07± 19.586	125.33±17.822	<0.001
Hb at Discharge, g/L	124.26±18.368	129.20±19.139	0.002
ΔHb	−14.82±7.28	3.87±7.376	<0.001
Plt at Admission, 109	232.54±83.674	239.79±93.193	0.390
Plt at Discharge, 109	234.56±87.940	257.99±95.331	0.005
ΔPlt	2.02±81.485	18.2±67.153	0.003
Critically ILL, %	57.7	51.0	0.126
Pneumonia, %	59.0	59.8	0.848
Bronchiectasis, %	23.1	20.3	0.435
Interstitial Lung Disease, %	4.7	5.7	0.594
Pleural Effusion, %	6.0	10.5	0.066
Type I Respiratory Failure, %	15.8	14.9	0.763
Type II Respiratory Failure, %	10.7	11.5	0.770
Non-invasive Ventilator, %	6.4	11.1	0.059
Invasive Ventilator, %	0.9	0.7	0.813
Fiberoptic Bronchoscopy, %	11.5	11.1	0.888

Notes: For continuous data, description statistics was expressed as mean and standard deviation. For binary variable data, description statistics was expressed as the ratio of positive patients.

Abbreviations: BMI, Body Mass Index; Hb, hemoglobin; Plt, platelet; Δ, D-value between discharge and admission; COPD, chronic obstructive pulmonary diseases.

Table 2 Multivariable Logistic Analysis to Determine Risk Factors of Δhb

Covariate	Estimate (B)	95% CI	P value
Age, y	1.020	1.008, 1.032	0.001
Male,	1.544	1.011, 2.358	0.044
Length of stay, d	1.069	1.000, 1.143	0.050
Blood Collection Volume, mL	1.021	1.010, 1.032	<0.001
Hb at Admission, g/L	1.052	1.039, 1.065	<0.001
Pleural Effusion	1.759	0.848, 3.65	0.129
Without a non-invasive Ventilator	1.997	0.982, 4.062	0.056

Notes: Risk of significant hemoglobin decline when per unit of covariate increased. P<0.05 were considered significant.

Abbreviation: Hb; hemoglobin.

Table 3 All Patients Were Grouped into Three Groups According to Hb at Admission, to Compare the Difference of Age, Gender, Blood Collection Volum, Δhb, Δplt Among the Three Groups

Variables	Anemia at Admission (n=101)	Normal Hb at Admission (n=384)	High Hb at Admission (n=45)	P value
Age, y	68.79±16.078	64.08±18.156	58.56±17.023	0.001
Blood collection volume, mL	66.19±30.479	60.57±21.576	63.27±19.979	0.271
ΔHb, g/L	−0.16±9.417	−4.14±11.457	−15.93±12.662	<0.001
Male gender, %	55.4	55.2	88.9	<0.001
ΔPlt, 109/L	16.30±77.852	12.33±73.958	−11.56±64.698	0.036

Notes: For continuous data, description statistics was expressed as mean and standard deviation. For binary variable data, description statistics was expressed as the ratio of positive subjects.

Abbreviations: Hb, hemoglobin; Plt, platelet; Δ, D-value between admission and discharge.

Figure 2 Grouping the patients based on hemoglobin value at admission to compare the difference of ΔHb among three groups. Group 1 referred to patients with anemia at admission, Group 2 referred to patients with normal hemoglobin values at admission, Group 3 referred to patients with high hemoglobin values at admission.