Generated on 2020-12-14

Introduction

Monitoring excess mortality provides understanding of the impact of COVID-19 during the course of the pandemic and beyond. Excess mortality in this report is defined as the number of deaths in 2020 which are above the number expected based on mortality rates in earlier years.

In this report the expected number of deaths is modelled using five years of data from preceding years to estimate the number of deaths we would expect on each day in 2020. Excess deaths are estimated by week and in total since 20 March 2020, based on the date each death was registered rather than when it occurred. Excess deaths are presented by age, sex, Upper Tier Local Authority, ethnic group, level of deprivation, cause of death and place of death.

All Persons

Weekly excess deaths by date of registration, North West.‎

Figure 1: Weekly excess deaths by date of registration, North West.‎

The trend in total excess deaths by week, in North West, since week ending 27 March 2020 is shown in Figure 1. Numbers above each of the columns show the total number of excess deaths and how these compare with the expected number based on modelled estimates for 2015 to 2019. For example, in week ending 10 April 2020 there were 1,480 excess deaths and this was over two times (2.2 times higher) the expected number of deaths in this week. When fewer deaths than expected occur in a week, the column is coloured grey.

Excess deaths where COVID-19 was mentioned on the death certificate are shown in orange. If the number of deaths is not shown in the orange part of the column, that means the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected in these weeks.

The number of excess deaths without COVID-19 mentioned on the certificate (shown in the white part of the column) may be due to an increase in deaths from other causes during the period of the pandemic but may also reflect under-reporting of deaths involving COVID-19.

Cumulative deaths since 20 March 2020, by date of registration, North West.

Figure 2: Cumulative deaths since 20 March 2020, by date of registration, North West.

The trend in the total cumulative number of excess deaths in North West since 20 March 2020 is shown in Figure 2.

Age Group Males

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by age group, males, North West.

Figure 3: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by age group, males, North West.

Figure 3A for males can be used to compare the cumulative total of excess deaths since 20 March 2020 between age groups.

Figure 3B compares the cumulative total of excess deaths among males with the number which would have been expected based on the modelled estimates for earlier years. Where the ratio of observed to expected is negative, this is shown in grey. The proportion of the excess where COVID-19 was mentioned on the death certificate is shown in yellow.

Table 1 - Males
Age group (years) Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
0-14 158 184 -* −26 0 -
15-44 972 825 1.18 147 72 48.8%
45-64 4,954 3,356 1.48 1,598 704 44.0%
65-74 6,286 4,744 1.32 1,542 1,247 80.9%
75-84 9,810 7,714 1.27 2,096 2,573 >100%+
85+ 8,571 7,448 1.15 1,123 2,169 >100%+

* registered deaths were not significantly different from expected deaths for the time period

+ the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected



Why ratios are important

Ratios can be useful for comparing between groups when the expected number is very different between groups.

For example, if group A had 5 excess deaths and group B had 10, it could appear that the impact was twice as high in group B. However, if the expected number of deaths was 1 in group A and 5 in group B, and the registered numbers of deaths were 6 and 15 respectively, then the ratios would show that group A experienced 6 times the number of deaths compared to expected, while group B experienced 3 times the number expected. Therefore, the actual relative impact is higher in group A.

The ratios presented in this report are relative to historical trends within each group, and not in relation to another group. For example, in the ethnicity section the ratio for the Asian group is the ratio between deaths in this group registered in 2020 and the estimate of expected deaths in the Asian group based on the preceding 5 years. It is not the ratio between the Asian group and another ethnic group.

Age Group Females

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by age group, females, North West.

Figure 4: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by age group, females, North West.

Figure 4A for females can be used to compare the cumulative total of excess deaths since 20 March 2020 between age groups.

Figure 4B shows the ratio of the observed to the expected deaths by age group among females since 20 March 2020. This chart can be used to compare the relative excess mortality between age groups.

Table 2 - Females
Age group (years) Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
0-14 145 144 -* 1 0 0.0%
15-44 603 456 1.32 147 47 31.9%
45-64 3,090 2,289 1.35 801 392 48.9%
65-74 4,360 3,332 1.31 1,028 723 70.4%
75-84 8,412 6,721 1.25 1,691 1,776 >100%+
85+ 12,882 11,308 1.14 1,574 2,553 >100%+

* registered deaths were not significantly different from expected deaths for the time period

+ the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected

Ethnic Group Males

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by ethnic group, males, North West.

Figure 5: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by ethnic group, males, North West.

Figure 5A for males can be used to compare the cumulative total of excess deaths since 20 March 2020 between ethnic groups.

Figure 5B shows the ratio of the observed to the expected deaths by ethnic group among males since 20 March 2020. This chart can be used to compare relative excess mortality between ethnic groups.

Table 3 - Males
Ethnic group Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Asian 843 501 1.68 342 315 92.1%
Black 274 155 1.77 119 83 69.4%
Mixed 91 70 -* 21 25 >100%+
Other 200 156 1.28 44 49 >100%+
White 28,479 22,637 1.26 5,842 6,042 >100%+

* registered deaths were not significantly different from expected deaths for the time period

+ the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected



Ethnic Group Females

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by ethnic group, females, North West.

Figure 6: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by ethnic group, females, North West.

Figure 6A for females can be used to compare the cumulative total of excess deaths since 20 March 2020 between ethnic groups.

Figure 6B shows the ratio of the observed to the expected deaths by ethnic group among females since 20 March 2020. This chart can be used to compare relative excess mortality between ethnic groups.

Table 4 - Females
Ethnic group Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Asian 587 367 1.60 220 179 81.6%
Black 186 108 1.72 78 44 57.0%
Mixed 74 54 -* 20 6 31.7%
Other 126 81 1.56 45 27 60.0%
White 27,704 22,926 1.21 4,778 5,027 >100%+

* registered deaths were not significantly different from expected deaths for the time period

+ the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected



Ethnicity coding

Ethnicity is not collected at death registration, so these estimates were made by linking death records to hospital records to find the ethnicity of the deceased. This approach has some limitations. Ethnicity is supposed to be self-reported by the patient in hospital records, but this may not always be the case. Patients may also report different ethnicities in different episodes of care. For this analysis the most recent reported ethnic group was used. Population estimates have been used to calculate mortality rates to estimate the expected numbers of deaths, and these were based on the 2011 Census. This may lead to a mismatch between ethnicity reported in hospital records and self-reported ethnicity in the census. It appears, for example, that more people are assigned to the ‘Other’ group in hospital records than in the 2011 Census.

Deprivation

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by deprivation quintile, North West.

Figure 7: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by deprivation quintile, North West.

Figure 7A can be used to compare the cumulative total of excess deaths since 20 March 2020 between deprivation quintiles.

Figure 7B shows the ratio of the observed to the expected deaths by deprivation quintile since 20 March 2020. This chart can be used to compare relative excess mortality between deprivation quintiles.

Table 5
Deprivation quintile Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Quintile 1 - Most Deprived 21,725 16,516 1.32 5,209 4,504 86.5%
Quintile 2 11,607 9,227 1.26 2,380 2,508 >100%*
Quintile 3 8,843 7,457 1.19 1,386 1,729 >100%*
Quintile 4 10,087 8,555 1.18 1,532 2,025 >100%*
Quintile 5 - Least Deprived 7,981 6,796 1.17 1,185 1,490 >100%*

* the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected

Upper Tier Local Authority

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by Upper Tier Local Authority, North West.

Figure 8: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by Upper Tier Local Authority, North West.

Figure 8A can be used to compare the cumulative total of excess deaths since 20 March 2020 between Upper Tier Local Authorities.

Figure 8B shows the ratio of the observed to the expected deaths by Upper Tier Local Authority since 20 March 2020. This chart can be used to compare relative excess mortality between Upper Tier Local Authorities.

Table 6
Upper Tier Local Authority Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Blackburn with Darwen 1,098 860 1.28 238 215 90.3%
Blackpool 1,449 1,232 1.18 217 248 >100%*
Bolton 2,264 1,759 1.29 505 496 98.2%
Bury 1,618 1,226 1.32 392 379 96.6%
Cheshire East 3,196 2,757 1.16 439 642 >100%*
Cheshire West and Chester 2,741 2,355 1.16 386 525 >100%*
Cumbria 4,767 3,814 1.25 953 752 78.9%
Halton 973 840 1.16 133 177 >100%*
Knowsley 1,316 1,059 1.24 257 245 95.2%
Lancashire 10,289 8,591 1.20 1,698 1,796 >100%*
Liverpool 4,049 3,013 1.34 1,036 943 91.0%
Manchester 3,032 2,300 1.32 732 646 88.2%
Oldham 1,816 1,434 1.27 382 479 >100%*
Rochdale 1,813 1,369 1.32 444 453 >100%*
Salford 1,894 1,454 1.30 440 477 >100%*
Sefton 2,881 2,206 1.31 675 525 77.8%
St. Helens 1,584 1,342 1.18 242 289 >100%*
Stockport 2,350 1,906 1.23 444 483 >100%*
Tameside 2,020 1,566 1.29 454 519 >100%*
Trafford 1,683 1,360 1.24 323 365 >100%*
Warrington 1,595 1,360 1.17 235 344 >100%*
Wigan 2,735 2,233 1.22 502 679 >100%*
Wirral 3,080 2,485 1.24 595 579 97.3%

* the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected

Deaths by underlying cause

See ICD10 references for the details of the ICD10 codes for each cause in this section.

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by underlying cause of death, North West.

Figure 9: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B) by underlying cause of death, North West.

Figure 9A shows the total cumulative excess deaths by UCOD since 20 March 2020. The chart can be used to compare the number of excess deaths for each UCOD.

This chart can be used to compare the cumulative total of excess deaths since 20 March 2020 between underlying causes.

Figure 9B shows the ratio of the observed to the expected deaths by UCOD since 20 March 2020. This chart can be used to compare relative excess mortality between underlying causes of death.

Table 7
Underlying cause of death Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Ischaemic Heart Diseases 5,392 5,088 1.06 304 140 46.0%
Cerebrovascular Diseases 2,627 2,445 1.07 182 93 51.0%
Other Circulatory Diseases 3,791 3,682 -* 109 80 73.7%
Cancer 13,715 13,734 -* −19 290 -
Acute Respiratory Infections 2,127 2,382 0.89 −255 2 -
Chronic Lower Respiratory Diseases 2,811 3,044 0.92 −233 63 -
Other Respiratory Diseases 803 1,093 0.73 −290 10 -
Dementia and Alzheimer's 6,553 6,218 1.05 335 212 63.4%
Diseases of the Urinary System 775 687 1.13 88 41 46.8%
Cirrhosis and Other Liver Diseases 1,115 1,040 -* 75 44 59.0%
Parkinson's Disease 553 581 -* −28 15 -
All Other Causes (Excl. COVID-19) 8,882 8,538 1.04 344 167 48.5%

* registered deaths were not significantly different from expected deaths for the time period

Place of Death

Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B), by place of death, North West.

Figure 10: Cumulative excess deaths (A) and the ratio of registered deaths to expected deaths (B), by place of death, North West.

Figure 10A shows the total cumulative excess deaths in each place of death since 20 March 2020. The chart can be used to compare the numbers of excess deaths in each place of death. This chart can be used to compare the cumulative total of excess deaths since 20 March 2020 between places of death.

Figure 10B shows the ratio of the observed to the expected deaths in each place of death since 20 March 2020. This chart can be used to compare relative excess mortality between places of death.

Table 8
Place of death Registered deaths Expected deaths Ratio registered / expected Excess deaths COVID-19 deaths COVID-19 deaths as % excess
Care Home (Nursing or Residential) 13,419 9,908 1.35 3,511 2,864 81.6%
Home 16,663 12,028 1.39 4,635 533 11.5%
Hospice 2,192 2,925 0.75 −733 129 -
Hospital (Acute or Community, not Psychiatric) 26,639 22,517 1.18 4,122 8,672 >100%*
Other Places 1,330 1,131 1.18 199 58 29.1%

* the total excess was less than the number of deaths with a mention of COVID-19, indicating fewer deaths from other causes than expected

Comparisons to other measures of excess deaths in England

The Office for National Statistics also publishes a weekly report on excess deaths in England & Wales. The numbers reported by ONS are broadly in line with the overall excess death figures in this report but there are some differences as the ‘expected’ numbers in this report are not just the simple five-year average for 2015 to 2019, as used by ONS. As explained in the Methods, they are instead modelled estimates which adjust for factors such as the ageing of the population and the underlying trend in mortality rates from year to year. The ONS report also defines weeks as seven-day periods ending on a Friday. Excess deaths in this report were estimated only for weekdays, with deaths registered on a Saturday added to the preceding Friday each week.

EuroMOMO is a European mortality monitoring programme that aims to measure excess deaths related to seasonal influenza and other public health threats that uses a standardised methodology across 24 European countries. The methodology used by EuroMOMO is similar to that used by the PHE model, however, the EuroMOMO model looks at deaths by date of occurrence, and the PHE model looks at deaths by date of registration. Because there is a time lag between date of occurrence of death and date of registration, analysis of excess deaths by date of occurrence requires a delay correction, the reliability of which improves over time. These two models produce very similar results but with small differences due to the delay correction applied by EuroMOMO.

The PHE Daily GRO mortality model is used in PHE’s COVID-19 surveillance report for all-cause mortality. It uses a 5-year average to estimate expected deaths, similar to that used by the ONS but with a trend included. It looks at deaths by date of occurrence based on rapidly reported deaths from the General Register Office and uses a registration delay correction, the reliability of which improves over time. Overall, the excess deaths are similar in the COVID-19 surveillance report and this report, but may show some differences in specific weeks due to use of occurrence date compared with registration date, and in recent weeks due to the delay corrections.

ICD10 references

Cause description ICD10 reference
Ischaemic heart diseases Underlying cause of death I20-I25
Cerebrovascular diseases Underlying cause of death I60-I69
Other circulatory diseases Underlying cause of death begins with I (excluding I20-I25 and I60-I69)
Cancer Underlying cause of death C00-C97
Acute respiratory infections Underlying cause of death J00-J22
Chronic lower respiratory diseases Underlying cause of death J40-J47
Other respiratory diseases Underlying cause of death begins with J (excluding J00-J22 and J40-J47)
Dementia and Alzheimer’s Underlying cause of death is F01, F03 or G30
Diseases of the urinary system Underlying cause of death is between N00-N39
Cirrhosis and other liver diseases Underlying cause of death is between K70-K76
Parkinson’s disease Underlying cause of death is G20
All other causes (excl. COVID-19) All other underlying causes of death (excluding COVID-19)

Back to underlying cause of death section

Code repository

The code used to create this report is stored here.