Nishanth D, Jhuma S, Nitesh G, Ramesh Chand M, Charanjit S, Gupta DK, Sen MK. COVID-19 with and without anosmia/dysgeusia: A case-control study. J Med Virol. 2021 Jan 8. doi: 10.1002/jmv.26784. Epub ahead of print. PMID: 33417259.

Background: Various new clinical signs and symptoms such as dysfunction of smell and taste i.e. anosmia and dysgeusia have emerged ever since the pandemic coronavirus disease (COVID-19) caused by Severe Acute Respiratory Syndrome coronavirus 2 (SARS-CoV-2) begun. The objective of this retrospective case control study was to identify clinical presentation and factors associated with ‘new loss/change of smell (anosmia) or taste (dysgeusia)’ at admission in patients positive by RT-PCR (real time polymerase chain reaction) for SARS-CoV-2 infection METHODS: All adult COVID-19 patients with new onset anosmia/dysgeusia at admission were included in study group. Equal number of age and gender matched COVID-19 patients without anosmia/dysgeusia at admission were included in control group.

Results: A total of 261 COVID-19 patients were admitted during study period of which 55 (21%) had anosmia and or dysgeusia. The mean (SD) age was 36(13) years. Majority were males (58%, n=32).Co-morbidity was present in 38% of cases (n=21).Anosmia (96%, n=53) was more common than dysgeusia (75%, n=41). Presence of both ansomia and dysgeusia was noted in 71% of patients(n=39).On comparing cases with controls, in univariate analysis, fever (higher in cases), rhinitis (lower in cases),thrombocytopenia,elevated creatinine and bilirubin (all higher in cases) were significantly associated with anosmia/dysgeusia.On multivariate analysis only rhinitis [OR: 95% CI:0.28 (0.09, 0.83);0.02] thrombocytopenia [0.99 (0.99, 0.99);0.01] and elevated creatinine [7.6 (1.5, 37.6);0.01] remained significant.

Conclusion: Anosmia and dysgeusia were noted in more than 1/5th of cases. Absence of rhinitis, low platelet counts and elevated creatinine were associated with anosmia/ dysgeusia in COVID-19 patients.