Excess deaths from all causes and dementia by setting Scotland 2020-2021

Headline Messages

Dementia is the main pre-existing medical condition in deaths involving COVID-19

From 16 March to 31 December 2020, there were 2,154 deaths registered involving COVID-19 where dementia was also mentioned on the death certificate. Of all deaths involving COVID-19 and dementia, only 3% (66 deaths) were registered with dementia as the main underlying cause. In contrast, 95% (2,038 deaths) were registered with COVID-19 as the main underlying cause (with the remaining 2% due to some other underlying cause). The number of deaths involving dementia that also had COVID-19 mentioned on the death certificate represented 99% of the number of excess deaths involving dementia. This supports our assumption that excess deaths registered involving dementia in 2020 (2,177) could almost wholly be attributed to COVID-19.

Further, the difference in excess deaths between dementia as the underlying cause or involving dementia is likely influenced by deaths being registered involving COVID-19, as 28% of all deaths involving COVID-19 in 2020 also had dementia mentioned on the death certificate. Dementia is, to date, the main pre-existing medical condition in all deaths involving COVID-19.

The proportion of deaths registered with dementia and COVID-19 in 2020 is higher than the 2015-2019 average proportion of people who died from influenza who also had dementia (15%, see supplementary table 3). However, it is worth noting that the 2015-2019 annual average of deaths involving influenza registered in Scotland was only 204, in sharp contrast to the 6,702 deaths registered in 2020 with COVID-19 mentioned on the death certificate. Therefore, it is difficult to make comparisons across the two conditions.

When considering the location of death where both COVID-19 and dementia was mentioned on the death certificate, 73% of deaths (1,577) occurred in care homes.

Deaths involving dementia in 2020 exceeded the 2015-2019 average

In 2020, there were 6,437 deaths registered with dementia as the underlying cause. This is 278 (+5%) more deaths than the 2015-2019 average (6,159) with the main spike observed in April 2020 (67% higher^[2]). However, when all registered deaths involving dementia are considered, there were 12,492 deaths where dementia was mentioned on the death certificate. This is 2,177 (+21%) more deaths than the 2015-2019 average number of deaths with dementia mentioned on the death certificate (10,315). Deaths from all causes exceeded the 2015-2019 average by 6,992 deaths (+12%).

Notes on annual dementia death statistics published by NRS

The 2021 NRS report Alzheimer's disease and other dementias published on 17 September shows that deaths registered with dementia as the underlying cause were 3% higher^[3] in 2020 compared to the 2015-2019 average and 10% higher in 2019 compared to the 2014-2018 average (see NRS table). This shows that excess deaths from dementia including Alzheimer's disease were lower in 2020 than in 2019 and sit within what might be expected as normal year-on-year variation. However, NRS note that these statistics are affected by a change in cause of death coding software at the beginning of 2017. For further comparison, annual excess deaths (all causes) 2001-2019 (see supplementary table 4) ranged from -4% to +6%.

Proportionally, excess deaths in care homes in 2020 exceeded excess deaths in all settings

A large proportion of excess deaths involving dementia in 2020 were registered to have occurred in care homes, a setting which has a high proportion of individuals diagnosed with dementia (estimated at 64% of residents in care homes for older people, see the Public Health Scotland Care home census). Further, 41% of deaths with COVID-19 as the underlying cause in 2020 were registered to have occurred in care homes. In 2020, there were 15,886 deaths (from all causes) registered in care homes. This is an excess of 2,352 deaths (+17%) compared to the 2015-2019 average (13,534). Proportionally, this is higher than excess deaths from all causes in all settings in 2020, which was +12% (64,823 registered deaths in 2020 compared to the 2015-2019 average of 57,831 deaths).

Figure 7 shows the proportion of deaths registered in 2020 in different settings. 25% of deaths from all causes (15,886) were registered in care homes in 2020, which is similar to the proportion of 2015-2019 average deaths from all causes registered in care homes (23%, 13,534).

Further, 69% of all deaths registered in 2020 with dementia as the underlying causeoccurred in care homes (4,424). This is the same proportion as that of all deaths registered with dementia as the underlying cause on average over 2015-2019 that occurred in care homes (69%, 4,236). 63% (7,837) of all deaths involving dementia registered in 2020 were in care homes, compared to a 2015-2019 average of deaths involving dementia in care homes of 60% (6,199).

This indicates that while excess deaths from all causes were higher in care homes than in all settings, the proportion of deaths registered in care homes in 2020 was proportionally only slightly increased when compared with previous years.

Deaths where dementia was the underlying cause were lower in hospital and higher at home/non-institutional setting in 2020

When looking at settings for deaths where dementia was the underlying cause in 2020, there were 329 excess deaths at home/non-institutional setting (+63% above the 2015-2019 average). Please note that the high percentage change is primarily due to a low number of weekly registrations and a low five-year average in this setting. At the same time, there were 237 fewer deaths in hospital (-18%) compared to the five-year average, suggesting that the excess deaths with dementia as the underlying cause at home/non-institutional setting may be due in part to a shift in location of deaths. For care homes, there were 188 excess deaths (+4%) with dementia as the underlying cause (see Fig. 6).

Deaths involving dementia were higher in care homes and at home/non-institutional setting, and slightly lower in hospital in 2020

For deaths involving dementia (mentioned on the death certificate) in 2020, there were 560 excess deaths at home/non-institutional setting (+56%), 1,638 excess deaths in care homes (+26%), and 41 fewer deaths compared to the 2015-2019 average in hospital (-1%).

The highest weekly number of deaths involving dementia in care homes (406) was recorded mid-way through the first wave of the COVID-19 pandemic in Week 17 2020 (week beginning 20 April 2020). This likely reflects COVID-19 deaths amongst people with dementia at this point in the pandemic since 51% of all deaths involving COVID-19 during this week in care homes also had dementia mentioned on the death certificate (207). COVID-19 involvement in deaths at this point may be underreported, since testing was less widespread outside hospital settings and there was less awareness of the full range of COVID-19 symptoms at the beginning of the first wave of the pandemic.

Average weekly excess deaths reduced over the course of the pandemic with the greatest reduction observed in care homes

There was a reduction in excess deaths (all causes and dementia-related) over the course of the pandemic. Three periods were compared, 16 March to 7 June 2020 (equivalent to the first wave), 28 September 2020 to 14 March 2021 (equivalent to the second wave) and 3 May to 8 August 2021 (when more than 90% of all older adults in care homes and care home staff had received two doses of a COVID-19 vaccine). Average weekly excess deaths were compared to account for the different length of time of each period.

The reduction in weekly average excess deaths was largely driven by a reduction in excess deaths observed in care homes. This may be a result of improved measures to reduce infection in care homes, and the vaccine rollout which prioritised care homes and older people, and/or due to higher 2015-2019 weekly average deaths during autumn/winter compared to spring/summer. However, further analysis would be required to establish the relative contribution, if any, of each of these factors.

The reduction in weekly average deaths may also be related to the peak in excess deaths caused by dementia at the start of the pandemic. Some of these deaths may have involved COVID-19 even if not registered on the death certificate, as indicated above, since testing was less widespread outside hospital settings and there was less awareness of all COVID-19 symptoms.

The gradual reduction in excess deaths over these three periods points to a positive effect of protective measures to reduce infections and/or the vaccine programme. However, related to the likely hastening of some deaths involving dementia, and the long period of restrictions, it is worth noting that death registrations during summer 2021 were much lower than the previous two periods. This lower number of registrations will have contributed to the overall trend of a reduction in excess deaths involving dementia.