Mortality and critical care unit admission associated with the SARS-CoV-2 lineage B.1.1.7 in England: an observational cohort study

Abstract

Background A more transmissible variant of SARS-CoV-2, the variant of concern 202012/01 or lineage B.1.1.7, has emerged in the UK. We aimed to estimate the risk of critical care admission, mortality in patients who are critically ill, and overall mortality associated with lineage B.1.1.7 compared with non-B.1.1.7. We also compared clinical outcomes between these two groups. Methods For this observational cohort study, we linked large primary care (QResearch), national critical care (Intensive Care National Audit & Research Centre Case Mix Programme), and national COVID-19 testing (Public Health England) databases. We used SARS-CoV-2 positive samples with S-gene molecular diagnostic assay failure (SGTF) as a proxy for the presence of lineage B.1.1.7. We extracted two cohorts from the data: the primary care cohort, comprising patients in primary care with a positive community COVID-19 test reported between Nov 1, 2020, and Jan 26, 2021, and known SGTF status; and the critical care cohort, comprising patients admitted for critical care with a positive community COVID-19 test reported between Nov 1, 2020, and Jan 27, 2021, and known SGTF status. We explored the associations between SARS-CoV-2 infection with and without lineage B.1.1.7 and admission to a critical care unit (CCU), 28-day mortality, and 28-day mortality following CCU admission. We used Royston-Parmar models adjusted for age, sex, geographical region, other sociodemographic factors (deprivation index, ethnicity, household housing category, and smoking status for the primary care cohort; and ethnicity, body-mass index, deprivation index, and dependency before admission to acute hospital for the CCU cohort), and comorbidities (asthma, chronic obstructive pulmonary disease, type 1 and 2 diabetes, and hypertension for the primary care cohort; and cardiovascular disease, respiratory disease, metastatic disease, and immunocompromised conditions for the CCU cohort). We reported information on types and duration of organ support for the B.1.1.7 and non-B.1.1.7 groups. Findings The primary care cohort included 198 420 patients with SARS-CoV-2 infection. Of these, 117 926 (59·4%) had lineage B.1.1.7, 836 (0·4%) were admitted to CCU, and 899 (0·4%) died within 28 days. The critical care cohort included 4272 patients admitted to CCU. Of these, 2685 (62·8%) had lineage B.1.1.7 and 662 (15·5%) died at the end of critical care. In the primary care cohort, we estimated adjusted hazard ratios (HRs) of 2·15 (95% CI 1·75–2·65) for CCU admission and 1·65 (1·36–2·01) for 28-day mortality for patients with lineage B.1.1.7 compared with the non-B.1.1.7 group. The adjusted HR for mortality in critical care, estimated with the critical care cohort, was 0·91 (0·76–1·09) for patients with lineage B.1.1.7 compared with those with non-B.1.1.7 infection. Interpretation Patients with lineage B.1.1.7 were at increased risk of CCU admission and 28-day mortality compared with patients...

Patients Admitted for Variant Alpha COVID-19 Have Poorer Outcomes than Those Infected with the Old Strain

“…Moreover, although different techniques for RT-PCR were used for our patients, we found that viral loads, measured according to the RT-PCR cycle threshold values in nasal swabs, were higher in the variant alpha group (data not shown). These results are in line with those reported by Davies et al [21], Challen et al [10] and Patone et al [22] but differed from Frampton et al who, despite observing higher viral loads, found no association with disease severity [11]. Moreover, in line with the results from Patone et al the worse outcome in the variant alpha group cannot be explained by time-dependent factors as the duration of symptoms were similar and the availability of ICU bed did not significantly change between groups.…”

Increased risk of hospitalisation and intensive care admission associated with reported cases of SARS-CoV-2 variants B.1.1.7 and B.1.351 in Norway, December 2020 –May 2021

“…We found that B.1.1.7 infection was associated with higher risk of ICU admission compared to non-VOC, in line with other studies [ 7 , 9 ]. However, when we restricted our study population to hospitalised cases, we found no difference in the risk of ICU admission between B.1.1.7 and non-VOC.…”

“…In a separate analysis, we have also found no difference in the time from symptom onset to hospitalisation, length of stay in hospital or ICU, nor odds of mortality up to 30 days post discharge for persons infected with B.1.1.7 compared to non-VOC in Norway [ 17 ]. Several studies from the UK have also found no evidence of an association between severe disease, death, and/or need for increased ICU resources among hospitalised patients infected with B.1.1.7, compared to other lineages [ 9 , 18 – 20 ]. This suggests that, while B.1.1.7 seems to increase the risk of hospitalisation, other patient characteristics may determine patient trajectories and healthcare required among those hospitalised with COVID-19.…”

Risk prediction of covid-19 related death and hospital admission in adults after covid-19 vaccination: national prospective cohort study

“…We did not include information on different variants that emerged during the study period owing to incomplete data, particularly in those patients admitted to hospital. 39 While we accounted for many risk factors for covid-19 mortality, some risks could remain, such as those conferred by rare medical conditions or other factors associated with exposure (eg, occupation) that are poorly recorded in general practice or hospital records and that might be being proxied to some extent by the covariates included. We did not distinguish vaccination type because this study was not designed to compare vaccine effectiveness.…”