| Authors | Patients with OD | Patients with OD + GD | Mode of collecting data | Objective assessment of OD | Onset of OD (days) | Duration of OD (days) | Recovery time (days) | Treatment given |
|---|---|---|---|---|---|---|---|---|
| Horvath et al87 | 66/102 (65.0%) Hyposmia-23.0%; anosmia42.0% | 75/102 (74.0%) | Online questionnaire | - | - | - | - | - |
| Shaikh et al88 | 34/1070 Hyposmia-3.2% Anosmia-7.3% | 150 (14.0%) | Questionnaire | - | - | - | - | - |
| Khan et al89 | Anosmia/hyposmia 19/224 (8.4%) | 64/224 (28.6%) | Questionnaire | UPSIT function scores normal-142 (63.4%); mild hyposmia 39 (17.4%); moderate hyposmia 18 (8.0%); severe hyposmia 13 (5.8%); anosmia 12 (5.4%) | Within 5 days-(58/102 (56.8%) First sign-10.1% Sudden in onset-7.1% | - | - | - |
| Lee et al90 | Anosmia-89/350 (25.4%) Hyposmia-56/350 (16.0%) | - | Telephone | - | First symptom-10% | - | 4 weeks (90.4%) | - |
| Koul et al91 | 83/231 (55.33%) Anosmia-57.3%; hyposmia-28.7% | 46/231 (30.7%) | Questionnaire | - | - | - | 1 month (78.0%) | - |
| Kandemirli et al92 | Anosmia-23/23 | - | Questionnaire | Sniffin’ Sticks test Threshold-1 (1±2.25); discrimination-2 (0±3); identification-3 (0±4); TDI-4 (1±8.5) | Sudden onset-4/23; after-12 concomitant-07 | - | - | - |
| Altundag et al93 | Anosmia/hyposmia-80/135 (59.3%) | - | Telephone | VAS scores-Group 1-8.4±1.9; Group 2-7.6±2; Group 3-6.2±2.6 | - | 7.8±3.1 (2-15) days | Group 1/2/3-28.6%/50.0%/66.7% | - |
| Dev et al94 | Anosmia-53/55 (96.0%) | 39 (71.0%) | Medical records | Mean VAS scores 5.52±2.08 | 7 days | - | 30 days | |
| Korkmaz et al95 | Anosmia/hyposmia-43/116 (37.9%) | - | Questionnaire | - | - | - | - | - |
| Babaei et al96 | Anosmia-207/235 (88.5%)-4 weeks and 219 (93.2%)-8 weeks | - | Interview | - | First symptom-23 (9.8%); Onset (mean)-3.88 day | - | 19.42±8.81 days | - |
| Nouchi et al97 | Hyposmia 129/390 (33.0%) | 106 (27.0%) | Telephone | - | - | - | Persistent hyposmia-34.0% | - |
| Polat et al98 | Anosmia 72/217 (33.2%) | - | Interview | - | 3 (1-13) days | - | 13 (3-30) days | - |
| Renaud et al99 | 43/51 (84.3%) Anosmia 23 (45.1%) Hyposmia 27 (52.9%) Parosmia 14 (27.5%) Phantosmia 13 (25.5%) | - | Questionnaire | CCCRC-QOD scores ranges 0-10/11-25/26-50/51-75/76-90/91-95/96-t-5 (9.8%)/3 (5.8%)/9 (17.7%)/9 (17.7%)/13 (25.5%)/5 (9.8%)/7 (13.7%) Identification test-5 (9.8%)/5 (9.8%)/6 (11.8%)/7 (13.7%)/9 (17.7%)/9 (17.7%)/10 (19.5%)/ | - | - | After 4 months-<15/16-30/30-60/60-90-11(47.8%)/5 (21.7%)/6 (26.1%)/1 (4.4%) | - |
| Rizzo et al100 | 110/202 (60.1%) Normosmia 58 (28-34) Microsmia 77 (16-27) Anosmia-10 (5-15) | - | Telephone | CAUPSIT score-25.5; mildly microsmic-54(37.2%); moderately microsmic 16 (11.0%); severely microsmic-7 (4.8%); anosmic 10 (6.9%) | - | - | Complete resolution/partial/no improvement 85 (77.3%)/22 (20.0%)/3 (2.7%) | - |
OD: olfactory dysfunction, GD: gustatory dysfunction, UPSIT: University of Pennsylvania smell identification test, TDI: olfactory test, VAS: visual analog scale, CCCRC-QOD: connecticut chemosensory clinical research center - questionnaire of olfactory disorders, CAUPSIT: culturally adapted University of Pennsylvania smell identification test