Table II.
Result of laboratory tests in patients with new-onset asthma following COVID-19 infection
| Case number | 1 | 2 | 3 | 4 | 5 | 6 |
|---|---|---|---|---|---|---|
| LLN of FEV1/FVC∗ | 61.7 | 76.0 | 73.4 | 78.3 | 70.6 | 66.5 |
| LLL of FEV1, L† | 1.57 | 2.29 | 2.06 | 3.56 | 1.64 | 2.32 |
| Spirometry during study period, n | 3 | 1 | 4 | 4 | 3 | 2 |
| Baseline spirometry‡ | ||||||
| FEV1/FVC % | 41.7 | 75.3 | 73.4 | 78.3 | 78.7 | 67.4 |
| FEV1, L | 1.03 | 2.49 | 2.07 | 3.74 | 1.92 | 3.63 |
| FEV1%pred | 31.9 | 79.2 | 68.5 | 83.8 | 84.4 | 93.9 |
| Post-BD FEV1/FVC | 42.4 | 80.7 | 76.5 | 83.2 | 79.2 | 73.3 |
| Post-BD FEV1, L | 1.08 | 2.55 | 2.27 | 4.11 | 1.99 | 3.94 |
| Post-BD FEV1%pred | 33.7 | 81.1 | 75.1 | 91.9 | 87.1 | 101.9 |
| Post-treatment spirometry | ||||||
| FEV1/FVC | 69.5 | NA | 84.4 | 81.9 | 77.4 | 66.0 |
| FEV1, L | 3.25 | NA | 2.65 | 4.13 | 1.79 | 3.55 |
| FEV1%pred | 101.2 | NA | 86.7 | 92.6 | 78.5 | 91.9 |
| Post-BD FEV1/FVC | 71.1 | NA | 87.0 | 83.3 | 80.3 | 72.4 |
| Post-BD FEV1, L | 3.32 | NA | 2.64 | 4.33 | 1.86 | 3.80 |
| Post-BD FEV1%pred | 103.6 | NA | 86.5 | 96.9 | 81.7 | 98.4 |
| BDR | Negative | Negative | Negative | Negative | Negative | Negative |
| MBPT (PC20, mg/mL)§ | NA | Positive (7.17) | NA | Positive (10.08) | Positive (0.77) | Positive (13.13) |
| Baseline FeNO, ppb‡ | 156 | NA | 85 | 39 | 13 | 119 |
| Posttreatment FeNO, ppb | 58 | NA | 77 | 58 | 19 | 105 |
| Baseline blood eosinophils, /uL | 1219 | 597 | 585 | 297 | 510 | 393 |
| Total IgE, IU/mL | NA | NA | NA | 44.5 | 118.0 | 89.6 |
| Skin prick test | Negative | NA | Negative | NA | Negative | NA |
| MAST | NA | NA | NA | Positive for DP and DF | NA | Negative |
BD, Bronchodilator; BDR, bronchodilator response; DP, Dermatophagoides pteronyssinus; DF, Dermatophagoides farina; FeNO, fractional exhaled nitric oxide; FVC, forced vital capacity; IgE, immunoglobulin E; LLN, lower limit of normal; MAST, multiple allergen simultaneous test; NA, not available; PC20, provocation concentration causing a 20% fall in FEV1; %pred, % predicted value
The LLN for FEV1/FVC was calculated for each subject using the new reference equations by Korean population. These were based on the predicted value – 1.645 × the standard error of the estimate.
The LLN for FEV1 was calculated for the mean – 1.645 × the SD by spirometry data of Korean population according to the age groups.
The first tests were performed at the time of the first visit to the outpatient clinic owing to symptoms after COVID-19 infection.
Positive MBPT was defined as PC20 < 16 mg/mL.