Excess mortality in North West - 21 March 2020 to 04 June 2021

What’s new in this report

The model used to estimate expected deaths has been revised to allow better precision of estimates by age, ethnic group and deprivation. Full details are available in the methodology document. These do not significantly affect overall figures.

We have updated the presentation of cause of death information. The difference is in the difference in how “cause” is defined. The new report shows the excess deaths by mention of cause of death, that is, a cause that appeared somewhere on the death certificate. The previous reports showed the excess deaths by underlying cause of death. Analysis of excess deaths by underlying cause were hard to interpret as they were affected by the fact that COVID-19, a new cause of death, was often the underlying cause of death instead.

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 throughout the pandemic 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 week through the pandemic. Excess deaths are estimated by week and in total since 21 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. Please note, some of the figures in this report have been rounded, though the differences displayed are based on unrounded data.

All Persons

Weekly excess deaths by date of registration, North West.&lrm;

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 24 April 2020 there were 1,557 excess deaths and this was two times (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.

Figure 2: Cumulative deaths since 21 March 2020, by date of registration, North West.

The trend in the total cumulative number of excess deaths in North West since 21 March 2020 is shown in Figure 2.

Age Group Males

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 21 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
0-24	463	542	0.85	−79	4	-
25-49	2,578	2,256	1.14	322	248	77.1%
50-64	7,489	5,805	1.29	1,684	1,251	74.3%
65-74	10,523	8,907	1.18	1,616	2,141	>100%^*
75-84	16,347	13,466	1.21	2,881	4,075	>100%^*
85+	14,276	12,717	1.12	1,559	3,549	>100%^*
Total	51,676	43,694	1.18	7,982	11,268	>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

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

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 21 March 2020 between age groups.

Figure 4B shows the ratio of the observed to the expected deaths by age group among females since 21 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
0-24	330	348	-^*	−18	5	-
25-49	1,644	1,366	1.20	278	173	62.3%
50-64	4,681	3,974	1.18	707	725	>100%⁺
65-74	7,429	6,253	1.19	1,176	1,351	>100%⁺
75-84	13,995	11,722	1.19	2,273	2,877	>100%⁺
85+	21,277	19,210	1.11	2,067	4,257	>100%⁺
Total	49,356	42,873	1.15	6,483	9,388	>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

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 21 March 2020 between ethnic groups.

Figure 5B shows the ratio of the observed to the expected deaths by ethnic group among males since 21 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	1,496	966	1.55	530	608	>100%^*
Black	488	287	1.70	202	153	76.0%
Mixed	146	135	-⁺	10	37	>100%^*
Other	305	277	-⁺	28	77	>100%^*
White	48,635	41,451	1.17	7,183	10,382	>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 ⁺ registered deaths were not significantly different from expected deaths for the time period

Ethnic Group Females

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 21 March 2020 between ethnic groups.

Figure 6B shows the ratio of the observed to the expected deaths by ethnic group among females since 21 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	1,017	725	1.40	292	343	>100%^*
Black	343	218	1.57	125	79	63.1%
Mixed	138	106	1.31	32	18	55.7%
Other	221	146	1.52	76	48	63.0%
White	47,130	41,120	1.15	6,009	8,883	>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

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

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 21 March 2020 between deprivation quintiles.

Figure 7B shows the ratio of the observed to the expected deaths by deprivation quintile since 21 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	36,170	29,962	1.21	6,208	7,495	>100%^*
Quintile 2	19,406	16,489	1.18	2,917	4,218	>100%^*
Quintile 3	15,030	13,153	1.14	1,877	3,018	>100%^*
Quintile 4	16,934	14,978	1.13	1,956	3,399	>100%^*
Quintile 5 - Least Deprived	13,492	11,984	1.13	1,508	2,526	>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

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 21 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 21 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	1,897	1,531	1.24	366	468	>100%^*
Blackpool	2,528	2,188	1.16	340	472	>100%^*
Bolton	3,752	3,120	1.20	632	798	>100%^*
Bury	2,681	2,176	1.23	505	606	>100%^*
Cheshire East	5,309	4,921	1.08	388	1,042	>100%^*
Cheshire West and Chester	4,723	4,190	1.13	533	992	>100%^*
Cumbria	8,132	6,778	1.20	1,354	1,499	>100%^*
Halton	1,620	1,498	-⁺	122	305	>100%^*
Knowsley	2,219	1,885	1.18	334	439	>100%^*
Lancashire	17,597	15,288	1.15	2,309	3,345	>100%^*
Liverpool	6,628	5,355	1.24	1,273	1,432	>100%^*
Manchester	4,971	4,089	1.22	882	1,054	>100%^*
Oldham	3,017	2,546	1.18	471	728	>100%^*
Rochdale	3,000	2,433	1.23	567	677	>100%^*
Salford	3,093	2,595	1.19	498	658	>100%^*
Sefton	4,746	3,920	1.21	826	914	>100%^*
St. Helens	2,777	2,392	1.16	385	550	>100%^*
Stockport	3,827	3,396	1.13	431	767	>100%^*
Tameside	3,225	2,794	1.15	431	749	>100%^*
Trafford	2,778	2,422	1.15	356	560	>100%^*
Warrington	2,742	2,428	1.13	314	576	>100%^*
Wigan	4,508	3,984	1.13	524	1,026	>100%^*
Wirral	5,262	4,412	1.19	850	999	>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 ⁺ registered deaths were not significantly different from expected deaths for the time period

Deaths by cause

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

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

Figure 9A shows the total cumulative excess deaths with mention of specific causes anywhere on the death certificate since 21 March 2020. The chart can be used to compare the number of excess deaths for each cause.

This chart can be used to compare the cumulative total of excess deaths since 21 March 2020 between causes.

Figure 9B shows the ratio of the observed to the expected deaths by cause of death since 21 March 2020. This chart can be used to compare relative excess mortality between causes mentioned anywhere on the death certificate.

Table 7

Cause of death mentioned on death certificate	Registered deaths	Expected deaths	Specific cause deaths (underlying cause)	COVID-19 deaths (underlying cause)	Excess deaths	Ratio registered / expected
Ischaemic Heart Diseases	18,125	15,932	9,429	2,463	2,193	1.14
Cerebrovascular Diseases	8,737	7,621	4,506	1,177	1,116	1.15
Other Circulatory Diseases	31,886	27,123	6,547	5,751	4,763	1.18
Heart Failure	11,329	10,190	1,391	1,691	1,139	1.11
Cancer	27,163	26,345	22,973	1,776	818	1.03
Acute Respiratory Infections	23,436	17,355	3,426	9,876	6,081	1.35
Chronic Lower Respiratory Diseases	13,731	11,958	4,572	3,375	1,773	1.15
Other Respiratory Diseases	6,872	7,758	1,365	1,120	−886	0.89
Dementia and Alzheimer's	17,762	15,286	10,479	3,860	2,476	1.16
Diseases of the Urinary System	12,224	10,219	1,249	2,553	2,005	1.20
Cirrhosis and Other Liver Diseases	3,650	3,227	1,976	304	423	1.13
Diabetes	11,655	8,023	995	3,259	3,632	1.45
Parkinson's Disease	1,796	1,577	923	375	219	1.14

Table 7 shows the number of registered deaths with a cause of death mentioned anywhere on the death certificate, the number expected, the excess deaths and the ratio of registered/expected deaths. It also breaks down the number of registered deaths with that cause registered on the death certificate by the number where the cause was the underlying cause and the number where COVID-19 was the underlying cause.

Place of Death

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 21 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 21 March 2020 between places of death.

Figure 10B shows the ratio of the observed to the expected deaths in each place of death since 21 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)	20,590	17,832	1.15	2,758	4,124	>100%^*
Home	28,120	21,146	1.33	6,974	1,033	14.8%
Hospice	3,666	5,047	0.73	−1,381	248	-
Hospital (Acute or Community, not Psychiatric)	46,379	40,295	1.15	6,084	15,149	>100%^*
Other Places	2,277	1,977	1.15	300	102	34.0%
^* 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.

PHE produces other estimates of excess mortality using the daily General Register Office model and the EuroMOMO model. These are reviewed in this blog.

Updates to Excess Mortality Methodology, December 2020

Several changes to the models were introduced in the regional report from January 2020:

Estimates are modelled on weekly periods, rather than modelled on daily periods and aggregated to weeks for publication
Weeks begin on Saturday and end on Friday, rather than Sunday to Saturday. This is consistent with ONS reporting weeks
The ONS Annual Death Extract is used as the source for 2019 deaths, instead of the previous (provisional) weekly data from the Mortality & Births Information System (MBIS)
2019 mid-year population estimates are now used instead of 2019 population projections
The model now includes additional interaction terms for age and time of year (seasonality), age and deprivation, and age and ethnic group

The methodology document has been updated to reflect these changes.

Links to historic reports

ICD10 references

Cause description	ICD10 reference
Ischaemic heart diseases	All mentions of I20-I25
Cerebrovascular diseases	All mentions of I60-I69
Other circulatory diseases	All mentions beginning with I (excluding I20-I25 and I60-I69)
Heart failure	All mentions of I11.0, I25.5, I42.0, I42.9, I50.0, I50.1, I50.9
Cancer	All mentions of C00-C97
Acute respiratory infections	All mentions of J00-J22
Chronic lower respiratory diseases	All mentions of J40-J47
Other respiratory diseases	All mentions beginning with J (excluding J00-J22 and J40-J47)
Dementia and Alzheimer’s	All mentions of F01, F03, or G30
Diseases of the urinary system	All mentions of N00-N39
Cirrhosis and other liver diseases	All mentions of K70-K76
Diabetes	All mentions of E10-E14
Parkinson’s disease	All mentions of G20