3.2 Mortality
Amongst the patients surveyed, 26% of the patients admitted succumbed to the disease during April 2021, while only 10% died with infection caused by Omicron during January 2022. It was observed that the older age group patients [age: 68.6 ± 9.76 years (mean ± SD)] had an increased mortality when infected with the Omicron variant, however, there was no significant difference in the age of patients who survived [age: 46.4 ± 16.1 years (mean ± SD)] to those who died [age: 49 ± 15.2 years (mean ± SD)] when infected with the Delta variant. In total, 32.6% of the male patients who were admitted died from the Delta variant infection, compared to 20.6% of the female patients who passed away within the same time. However, amongst the patients admitted with Omicron infection, a higher percentage of females (11.6%) than males (8.7%) perished. There was no mortality seen amongst the pregnant females admitted due to the infection by SARS-CoV-2 in both the time periods.
The comorbidities such as hypertension, diabetes and chronic obstructive pulmonary disease had an increased risk for mortality for patients infected by either the Delta or the Omicron variant, with a significant odds ratio as seen in Table I. On comparison of the patients who succumbed to the disease in the two different periods, patients with chronic obstructive pulmonary disease had increased mortality (30.8%) when infected with the Delta variant as compared to the Omicron variant (20%). Although, the presence of comorbidities was not a risk factor to get admitted in Omicron, the presence of diabetes, hypertension and chronic obstructive pulmonary disease had a higher risk of mortality as compared to the Delta variant as shown in Table I. The risk of smoking increased the mortality (OR: 1.5-1.7) in both variants of the infection.
In patients who succumbed to the disease, higher proportion of the patients were admitted for more than 7 days due to the Omicron infection (80%) as compared to the Delta infection (30.8%). Most of the patients succumbed within 48 hours (30.8%) or after 48 hours but within 7 days (38.4%) during the Delta variant infection. However, in patients with Omicron, none of them died within 48 hours. The average length of stay amongst patients who were admitted and later died was comparatively longer in cases infected with the Omicron variant than the Delta variant (12.1±4 vs 5.2±4 days).