Table 1.
Characteristics of trial participants at baseline.
| Intervention Groups | |||
|---|---|---|---|
| Characteristics | Combination (n = 9) |
Standard Care (n = 8) |
Control (n = 5) |
| Median age (IQR)–year | 36 (26.0–43.0) | 49 (37.3–56.3) | 58 (50.0–61.0) |
| Female sex–no. (%) | 5 (56) | 6 (75) | 3 (60) |
| Tobacco smoker–no. (%) | 3 (33) | 0 (0) | 0 (0) |
| Coexisting conditions–no. (%) | |||
| Good past health | 8 (89) | 4 (50) | 2 (40) |
| Diabetes mellitus | 0 (0) | 0 (0) | 1 (20) |
| Hypertension | 0 (0) | 1 (13) | 2 (40) |
| Hyperlipidaemia | 1 (11) | 0 (0) | 1 (20) |
| Atherosclerotic diseases | 0 (0) | 2 (25) | 1 (20) |
| Rheumatological conditions | 1 † (11) | 0 (0) | 0 (0) |
| Malignancies | 0 (0) | 0 (0) | 2 ‡ (40) |
| History of haematological or solid organ transplantation | 0 (0) | 0 (0) | 0 (0) |
| SARS-CoV-2 diagnosis | |||
| Positive RT–PCR–no. (%) | 9 (100) | 8 (100) | 5 (100) |
| CT values (IQR) | 22.1 (18.1–29.0) | 20.1 (15.1–21.7) | 17.2 (15.7–22.8) |
| COVID–19 disease severity | |||
| Mild disease–no. (%) | 9 (100) | 8 (100) | 5 (100) |
| COVID–19-related OD, onset and duration (IQR)–days | |||
| Onset of OD from first COVID–19 symptom | 0.0 (0.0–7.0) | 4.0 (1.8–16.0) | 3.0 (0.0–3.0) |
| Median duration of COVID–19-related OD | 159 (130.0–163.0) | 164.5 (118.3–180.3) | 138.0 (135.0–225.0) |
| COVID–19-related OD, symptomatology–no. (%) | |||
| OD onset | |||
| Sudden | 6 (67) | 6 (75) | 1 (20) |
| Gradual | 3 (33) | 2 (25) | 4 (80) |
| OD characteristics | |||
| Anosmia | 4 (44) | 5 (63) | 2 (40) |
| Hyposmia | 4 (44) | 2 (25) | 3 (60) |
| Parosmia | 1 (11) | 3 (38) | 0 (0) |
| Hyperosmia | 0 (0) | 0 (0) | 0 (0) |
| Phantosmia ※ | 2 (22%) | 1 (13) | 0 (0) |
| Olfactory assessments–mean (SD) | |||
| Modified LK score | 0.7 (1.0) | 0.0 (0.0) | 0.0 (0.0) |
| BTT | 2.9 (1.1) | 2.0 (1.1) | 1.8 (1.0) |
| SIT | 24.6 (7.7) | 24.5 (6.3) | 19.6 (9.0) |
| SIT category–no. (%) | |||
| Normosmia | 1 (11) | 0 (0) | 0 (0) |
| Mild microsmia | 1 (11) | 2 (25) | 0 (0) |
| Moderate microsmia | 3 (33) | 2 (25) | 1 (20) |
| Severe microsmia | 1 (11) | 2 (25) | 2 (40) |
| Anosmia | 3 (33) | 2 (25) | 2 (40) |
Combination = oral vitamin A in combination with olfactory training (OT). Standard care = OT alone. Control = clinical observation. † Rheumatoid arthritis, quiescent disease. ‡ Malignancy of the breasts, in remission. ※ Phantosmia, detection of rotten substances or burning wood. BTT = butanol threshold test; COVID–19 = coronavirus disease 2019; CT = cycle threshold; Modified LK score = modified Lund-Kennedy endoscopic score; OD = olfactory dysfunction; RT–PCR = reverse transcription–polymerase chain reaction; SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2; SD = standard deviation; SIT = smell identification test.