Greater COVID-19 Severity and Mortality in Hospitalized Patients in the Delta-phase Compared to the Others: A Single Center Prospective Registry.

BACKGROUND AND OBJECTIVE

To compare clinical and laboratory features, and outcomes in the second COVID-19 phase (delta variant) with the first and third phases in India we performed a registry-based study.

METHODS

Patients with confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were recruited over the study period from March 2020 to July 2022. In the first phase (wild type, March-December 2020) of the 7,476 suspected, 1,395 (18.7%) were positive and 863 (61.8%) were hospitalized, in the second phase (delta, January-July 2021) out of 8,680 suspected, 1,641 (19.4%) tested positive and 388 (23.6%) were hospitalized, and in the third phase (omicron, January-July 2022) out of 5,188 suspected patients, 886 (17.1%) tested positive and 94 (10.6%) were hospitalized. We compared details of admission clinical and laboratory features and in-hospital management and outcomes in the three phases.

RESULTS

A total of 2,352 patients were recruited. The majority of the patients were men, aged <45 years were 20% and about 20% of patients had hypertension, diabetes, and cardiovascular diseases. Patients in the second phase had significantly more cough, fever, shortness of breath, and lower oxygen saturation (SpO2) at admission and also had more lymphopenia, C-reactive proteins (CRPs), interleukin-6, ferritin, lactic dehydrogenase, and transaminases than patients in the other two phases. In the second vs the first and third phases, the requirement of supplementary oxygen (47.9 vs 33.1 and 23.4%), proning (89.2 vs 37.1 and 5.3%), high flow nasal oxygen (15.7 vs 8.71 and 5.3%), noninvasive ventilation (14.4 vs 9.1 and 11.7%), invasive ventilation (16.2 vs 9.1 and 9.6%), steroids (94.1 vs 83.4 and 37.2%), remdesivir (91.2 vs 73.8 and 39.4%), and anticoagulants (94.3 vs 83.0 and 61.7%) was significantly more (p < 0.001). The median length of stay in days [interquartile range (IQR)] was longer in the second phase [8 (6-10)] vs the first [7 (5-10)] and the third phase [4 (3-6) days]. The intensive care unit (ICU) stay in the second phase [9 (5-13) days] was also significantly more than the first [6 (2-10)] and third [0 (0-3)] phases (p <0.001). Overall, in-hospital deaths occurred in 176 patients (12.8%). Deaths were significantly higher in the second phase (19.3%), compared to the first (11.0%) and the third (3.3%) phases (p <0.01). We also observed that greater disease severity at presentation was associated with higher mortality in all the phases.

CONCLUSION

This study shows that COVID-19 patients that were hospitalized in the second (delta) phase of the epidemic had more severe disease compared to the first and third phases. In the second phase of patients, there was a significantly higher duration of hospitalization, ICU hospitalization, greater oxygen requirement, noninvasive and invasive ventilatory support, and more deaths.