The coronavirus disease 2019 (COVID-19) caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) was associated with a significantly increased mortality among populations with preexisting conditions [1], [2], [3]. There were increased SARS-CoV2 infections and hospitalisations reported among the younger population during the SARS-CoV2 B.1.617.2 (Delta variant) surge in the United Kingdom (UK) [4]. However, the impact of this demographic shift and the preexisting conditions among the SARS-CoV2 deaths during the Delta variant surge are not well known.
In this observational retrospective study, we analysed nationwide data of the presence or absence of preexisting conditions associated with COVID-19 deaths (n = 94 037) in the UK among various age groups prior to the Delta variant surge (all data since 2020 until 2 June 2021) and during the Delta variant surge (during 3 June 2021 to 13 October 2021) using COVID-19 the Weekly Total Deaths Archives of the National Health Service (NHS) database [5].
1. Statistical analysis
Statistical analysis: The percentage of SARS-CoV2 deaths among various age groups with and without preexisting conditions was also compared during the Delta variant surge since June 2021 (4 June through 8 October 2021) and prior to the Delta variant surge in 2021 [5]. The relative risk (RR), 95% confidence interval and P value were calculated to compare these outcomes prior to and during the Delta variant surge. RR is calculated using the formula, P value (<0.05) was considered significant for the differentiation between the groups.
Tables 1demonstrates the preexisting conditions prior to the Delta variant surge (all data since early 2020 to 2 June 2021) and since 3 June through 13 October 2021 during the Delta variant surge. Of the 94 624 total SARS-CoV2 deaths, 6824 deaths occurred during the Delta variant surge (13 June through 13 October 2021), and the remaining 87 213 SARS-CoV2 deaths occurred since the beginning of the COVID-19 pandemic until 2 June 2021. The majority of COVID-19 deaths among all age groups occurred with preexisting conditions (83 624 [95.9%] of 87 213 COVID-19 deaths since early 2020 until 2 June 2021 and 6296 [92.3%] of 6824 COVID-19 deaths from 3 June through 13 October 2021). There was slight but statistically significant increased percentage of COVID-19 deaths without preexisting conditions during the Delta variant surge than before (7.7% vs 4.1%; RR 1.03; P < 0.0001), with most of this increase in deaths occurring without preexisting conditions among those 20 to 39 years of age (27.7% vs 13.5%; RR 1.19, P = 0.0005) and 40 to 59 years of age (16.1% vs 9.8%; RR 1.07, P < 0.0001). Other age groups, except those 0 to 19 years of age, are associated with minor but statistically significant increases in the number of COVID-19 deaths without any preexisting conditions. The most common preexisting conditions associated with COVID-19 deaths were diabetes mellitus (26.3%), chronic kidney disease (16.7%), chronic pulmonary disease (15.9%), dementia (15.3%), ischemic heart disease (12.9%) and asthma (7.7%).
Table 2.
Preexisting conditions: Data on all deaths from early 2020 to 13 October 2021
| Date introduced | Preexisting condition | Preexisting condition present/total deaths (%) |
|---|---|---|
| 31 March 2020 | Diabetes | 24 333/92 441 (26.3%) |
| 31 March 2020 | Chronic kidney disease | 15 395/92 441 (16.7%) |
| 31 March 2020 | Chronic pulmonary disease | 14 733/92 441 (15.9%) |
| 31 March 2020 | Dementia | 14 177/92 441 (15.3%) |
| 1 May 2020 | Ischaemic heart disease | 9516/73 622 (12.9%) |
| 31 March 2020 | Asthma | 7145/92 441 (7.7%) |
| 31 March 2020 | Rheumatological disorder | 2916/92,441 (3.2%) |
| 31 March 2020 | Chronic neurological disorder | 2388/92 441 (2.6%) |
| 31 March 2020 | Other | 67 457/92 441 (73.0%) |
Table 1.
Presence or absence of preexisting conditions compared among various age groups
| Early 2020–2 June 2021 | 3 June 2021–13 October 2021 | ||||
|---|---|---|---|---|---|
| Preexisting condition | Preexisting condition | ||||
| Age group | Present, n (%) | Absent, n (%) | Present, n (%) | Absent, n (%) | |
| 0–19 y | 32 (80.0%) | 8 (20.0%) | 18 (75.0%) | 6 (25.0%) | RR 1.0667; 95% CI 0.8077 to 1.4087; P = 0.6493 |
| 20–39 y | 527 (86.5%) | 82 (13.5%) | 115 (72.3%) | 44 (27.7%) | RR 1.1964; 95% CI 1.0814 to 1.3238; P = 0.0005; |
| 40–59 y | 5664 (90.2%) | 613 (9.8%) | 727 (83.9%) | 140 (16.1%) | RR 1.0761; 95% CI 1.0440 to 1.1092; P < 0.0001; |
| 60–79 y | 31 862(95.5%) | 1514 (4.5%) | 2666 (93.5%) | 186 (6.5%) | RR 1.0212; 95% CI 1.0111 to 1.0315; P < 0.0001 |
| 80+ y | 45,539 (97.1%) | 1372 (2.9%) | 2770 (94.8%) | 151 (5.2%) | RR 1.0237; 95%CI 1.0149 to 1.0325; P < 0.0001 |
| Total (n = 94 037) | 83 624 (95.9%) | 3589 (4.1%) | 6296 (92.3%) | 528 (7.7%) | RR 1.0393; 95% CI 1.0320 to 1.0466; P < 0.0001 |
CI, confidence interval; RR, relative ratio.
NOTE: Data are compared for the period ending 2 June 2021 and for the period of 2 June to 13 October 2021.
Our study demonstrates that preexisting conditions were associated with the majority of deaths among older populations (>60 years of age), with a slight increase in deaths in those without preexisting conditions, especially among younger populations, during the Delta variant surge. Our study included a detailed analysis of a large sample of 94 624 SARS-CoV2 deaths among various age groups from the UK NHS database. A limitations of our study is that it is an observational retrospective study of publicly reported data, and the generalisability of the findings are limited to the UK population. Additionally, we are unable to analyse the mode of COVID-19 deaths and timing of deaths relative to the onset of symptoms and or hospitalisation, as that information is not available.
In conclusion, the majority of deaths (93.5%–94.8%) among those older than 60 years of age during the Delta variant surge were associated with preexisting conditions, with a slight but statistically significant increased proportion of deaths in those without preexisting conditions (7.7% vs 4.1%) during the Delta variant surge than the prior comparision period before the Delta variant surge, and the majority of this slight increase was seen among those aged 20 to 39 and 40 to 59 years.
Acknowledgments
Competing interests
The authors have no conflict of interest or financial relationships relevant to the submitted review to disclose.
Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sector.
Ethical approval
None required.
Editor: Prof Guido Antonelli
References
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