Table 1. Demographics and clinical characteristics of study participants.
Continuous variables are presented as mean ± standard deviation. Categorical variables are presented as numbers (%).
| Total number | Healthy controls | Acute asthma | Acute COPD | Pneumonia | Heart failure | p value | |
|---|---|---|---|---|---|---|---|
| Total number of participants (n=) | 277 | 55 | 65 | 58 | 55 | 44 | |
| Demographics | |||||||
| Age *, years | 60.8 ± (16.8) | 63.05 ± (11.78) | 44.3 ± (17.93) | 69.82 ± (8.16) | 60.67 ± (16.50) | 70.72 ± (11.04) | .124 |
| Gender Male (n=) (%) | 143 (51%) | 26 (47%) | 25 (38%) | 33 (56%) | 27 (49%) | 32 (72%) | .008 ¥ |
| Body Mass Index (BMI)*a | 29.5 ± (7.3) | 28.2 ± (4.5) | 31.5 ± (9.0) | 27.5 ± (7.7) | 29.2 ± (6.9) | 31.5 ± (6.5) | .767 |
| Smoking Current smoker (n=) (%) | 53 (19%) | 4 (7%) | 13 (20%) | 21 (36%) | 11 (20%) | 4 (9%) | .001 ¥ |
| Vital signs | |||||||
| Temperature (Celsius)* | 36.7 ± (0.6) | 36.1 ± (0.4) | 36.8 ± (0.5) | 36.7 ± (0.5) | 37.1 ± (0.7) | 36.5 ± (0.3) | .000 |
| Heart rate (beats/min)* | 87.2 ± (18.5) | 68.1 ± (9.54) | 99.6 ± (17.2) | 92.9 ± (15.6) | 90.3 ± (15.4) | 81.3 ± (15.6) | .005 |
| Respiratory rate (breaths/min)* | 18.9 ± (4.2) | 13.0 ± (1.8) | 20.5 ± (3.4) | 21 ± (2.5) | 20.4 ± (4.6) | 19.1 ± (1.8) | .000 |
| Oxygen saturations (%)* | 95.8 ± (3.0) | 97.7 ± (1.3) | 96.1 ± (2.5) | 94.0 ± (2.9) | 94.5 ± (0.5) | 96.5 ± (1.9) | .001 |
| Systolic Blood Pressure (mmHg)* | 131.5 ± (19.2) | 134 ± (15.7) | 133 ± (17.7) | 133 ± (20.5) | 126 ± (19.4) | 128 ± (22.2) | .515 |
| Total mEWS-2 score ^b | 1 (0-3) | 0 (0-1) | 2 (1-3.5) | 3 (1-5) | 2 (1-3) | 1 (0-2) | .000 |
| Breath sampling | |||||||
| Time from admission to breath sampling (hours)^ | 16 (3.0−23.0) | 1 (1-1) | 16 (9.2−22.7) | 18 (12.5-23.0) | 18 (11.0-23.0) | 23 (19.0-26.0) | .000 |
| Symptoms assessment | |||||||
| Breathlessness VAS score (mm)*c | 58.1 ± (31.6) | 6.2 ± (9.3) | 76.6 ± (14.2) | 71.6 ± (19.2) | 67.8 ± (22.1) | 67.9 ± (20.0) | .000** |
| Cough VAS score (mm) *c | 43.3 ± (33.2) | 8.7 ± (14.3) | 64.5 ± (26.7) | 57.8 ± (27.0) | 53.6 ± (30.6) | 24.3 ± (25.2) | .000** |
| Wheeze VAS score (mm) *c | 41.8 ± (34.9) | 3.4 ± (6.4) | 66.2 ± (24.5) | 60.3 ± (29.0) | 45.1 ± (34.8) | 28.1 ± (28.6) | .000** |
| eMRCd score (n=) (%) | |||||||
| 1 | 17 (6%) | 1 (1.5%) | 8 (13%) | 7 (12%) | 1 (2%) | .000¥ | |
| 2 | 6 (2%) | 0 (0%) | 0 (0%) | 5 (9%) | 1 (2%) | .000¥ | |
| 3 | 15 (5%) | 6 (10%) | 0 (0%) | 7 (12%) | 2 (4.5%) | .000¥ | |
| 4 | 50 (18%) | 16 (25%) | 11 (19%) | 6 (11%) | 17 (38.5%) | .000¥ | |
| 5a | 112 (40%) | 38 (51%) | 32 (55%) | 22 (41%) | 20 (46%) | .000¥ | |
| 5b | 21 (7%) | 3 (4.5%) | 7 (13%) | 8 (15%) | 3 (7%) | .000¥ | |
| Exposure to antibiotics and steroids within 2 weeks of hospital admission | |||||||
| Antibiotics (n=) (%) | 61 | n=0 (0%) | n=24 (36.9%) | n=23 (39.6%) | n=10 (18.2%) | n=4 (9.0%) | .002¥ |
| Steroids (n=) (%) | 57 | n=0 (0%) | n=28 (43.0%) | n=24 (41.3%) | n=3 (5.4%) | n=2 (4.5%) | .000¥ |
| Morbidity and mortality measures | |||||||
| Length of hospital stay (days) ^ | 3 (2-6) | 2.0 (1.0-3.0) | 4.0 (2.0-6.0) | 4.0 (2.0-5.0) | 7.0 (4.0-11) | .000** | |
| 30-60 days hospital readmission (n=) | 29 | 7 | 9 | 6 | 7 | .461¥ | |
| 1-year all-cause mortality | 12 | 0 | 1 | 5 | 1 | 5 | .078¥ |
| Laboratory parameters | |||||||
| C-reactive protein (CRP) (mg/L)^ | 11 (5.0-34.2) | 5 (5-5) | 10.0 (5.0-23.0) | 12.0 (5.0-20.7) | 108.0 (53.5-245.3) | 11.0 (5.0-22.0) | .000** |
| Blood Eosinophil count 109/L^ | 0.13 (0.06-0.24) | 0.17 (0.09-0.24) | 0.18 (0.06-0.42) | 0.13 (0.06-0.24) | 0.08 (0.04-0.14) | 0.13 (0.08-0.23) | .000** |
| Troponin T (ng/l)^ | 3.3 (1.0-11.4) | 2.05 (1.0-2.7) | 1.55 (1.0-3.4) | 3.75 (2.6-10.9) | 4.3 (2.18-11.3) | 20.2 (13.4-59.6) | .000** |
| Brain natriuretic peptide (BNP) (ng/l)^ | 40.5 (20.6-98.9) | 28.40 (17.60-39.88) | 20.4 (12.1-40.0) | 56.3 (24.3-95.0) | 56.3 (27.4-132.1) | 611.8 (172.1-1259.1) | .000** |
| Questionnaires | |||||||
| Asthma Quality of Life Questionnaire (AQLQ) total* | 65 | 117.3 ± (37.3) | |||||
| COPD Assessment test (CAT) * | 58 | 26.7 ± (7.3) | |||||
| COPD Decaf score * | 58 | 1.7 ± (0.8) | |||||
| CURB65 score^ | 55 | 2 (1-3) | |||||
| NYHA score^ | 44 | 2 (1-3) |
The body mass index (BMI) is the weight in kilograms divided by the square of the height in meters.
Modified Early warning score - 2 (MEWS-2) is a guide widely used by medical services to determine the degree of illness of a patient based on their vital signs including respiratory rate, oxygen saturations, temperature, blood pressure, and heart rate. Vital signs collected at the point of admission for acute disease groups.
Participants were asked to determine their degree of breathlessness, cough and wheeze on a 100mm visual analogue scale (VAS) on admission. Higher scores indicate worse symptoms.
Extended Medical research Council (eMRC) scale is a validated measure of perceived respiratory disability, scored from 1 to 5b. Higher scores indicate worse disability.
Data is expressed as mean (SD) or n (%) ± (SD)
Data expressed as median (IQ range)
Kruskal-Wallis test comparing non-parametric data, ¥ Pearson Chi Squared and Fisher’s Exact test.
ANOVA was used to assess the differences between groups for normally distributed continuous variables and Kruskal-Wallis for non-parametric continuous variables. Pearson chi-squared and Fisher’s exact were used to assess the differences in categorical variables. The results were considered statistically significant at p-values <0.05.