Hildegarde Naughton (Galway West, Fine Gael) | Oireachtas source

I welcome the opportunity to discuss trends in mortality and estimates of excess mortality. The Department of Health actively monitors and reviews all available data on mortality, including excess mortality, as it becomes available, to gain a better insight on underlying mortality trends in Ireland and factors influencing these. While the Department does not produce estimates of excess mortality, it works closely with the Health Protection Surveillance Centre, HPSC, the Central Statistics Office, CSO, and other stakeholders to monitor estimates of excess mortality. A number of different methodologies have been developed by organisations and academics internationally to try to estimate levels of excess mortality. It is important to note that estimation methods vary depending on a number of factors including differences in methodology and the data used. There is, therefore, no internationally agreed method on the estimation of excess mortality.

Official data on mortality in Ireland is collected by the CSO based on deaths registered with the General Register Office, GRO. The latest final data on deaths from the CSO is for the deaths occurring in 2020. Provisional data, based on date of registration of the death, is currently available for 2021 and 2022. It is important to note that in Ireland currently, a legal period of three months is allowed for the registration of a death. Analysis by the general register office has found that, on average, approximately 82% of deaths are registered within this three-month time frame and, therefore, data for the most recent period is provisional and caution is required in interpreting this data.

Ireland’s age-standardised all cause death rate declined steadily from 1,152 deaths per 100,000 in 2007 to 923 per 100,000 in 2019. In 2022, the provisional age-standardised all cause death rate was 937 per 100,000. While this was an increase from 2021, it was below the age-standardised all cause death rate of years prior to 2018. As most causes of death vary significantly with people's age and sex, the use of standardised death rates improves comparability over time and between countries.

A key factor potentially influencing mortality trends is demographic change and the changing age structure. Ireland’s total population increased by 8.1% between census 2016 and 2022. There was a fall in population in some younger age groups such as children under four years. In contrast, the number of persons in Ireland aged 65 and over increased by 22%, more than double the 10% increase that occurred in the EU 27 over the same period. Within this age category, the highest increase was experienced by those aged 75 to 84, growing by 28%, while the EU 27 only experienced a 3.4% increase in the 75 to 84 age group.

While Ireland continues to have a younger age profile than most of the EU, our population is ageing and coming more in line with the EU average. As we might expect, persons in older age groups account for the majority of deaths. In 2019, 82% of all deaths which occurred in Ireland were among persons aged 65 and over. Some 29% of all deaths were in the 75 to 84 age group. We know that the number of adults aged 65 years and older is increasing by just under 4% annually and the number of adults aged 75 and older is increasing by just over 4% a year. The substantial increase in the number of persons in these age groups annually gives rise to an expectation of an increase in the absolute number of deaths occurring in Ireland, compared with the number of deaths that occurred during the years 2016 to 2019.

All data on excess mortality are estimates and, as I noted earlier, many different methodologies have been developed by a number of organisations internationally to try to estimate levels of excess mortality. Some of these methodologies are long-established, such as EuroMOMO, a European mortality monitoring activity, while many were developed in response to the Covid-19 pandemic, such as by Eurostat and the CSO. It is important to note that the different estimation methods vary considerably in the estimation of expected deaths. For example, the number of years involved in the baseline average may vary, where 2016 to 2019, is a four-year average, while others use a single year. The actual timeline may vary, for example, the years 2016 to 2019 or 2010 to 2013. Methods may allow for seasonal variation. Methods may apply statistical significance tests before mortality is considered to be excess. Nationally and internationally, work is currently under way to further refine methods to estimate excess mortality.

EuroMOMO, Eurostat and the CSO have published estimates of excess mortality during winter 2022-23 for Ireland. The most recent estimates from EuroMOMO estimate that during winter 2022-23, Ireland experienced excess all cause mortality for all ages during five consecutive weeks in late December 2022 to early January 2023. Mortality has been close to or below baseline since the second week of January 2023. EuroMOMO estimates that other European countries, including the UK, Austria, Belgium, Denmark, France, Germany, Italy, the Netherlands, Portugal, Sweden and Switzerland, also experienced excess mortality for a period last winter when flu was circulating at high levels.

When considering the EuroMOMO data on excess mortality, it important to note that influenza activity was at very high levels in Ireland during December 2022 and early to mid-January 2023. The number of influenza case notifications to the HPSC in the last weeks of 2022 and early weeks of 2023 was the highest of any week since 2017. Previously, flu surges of this magnitude recorded similar increases in excess deaths in winter 2017-18, which was characterised as a severe flu season. While EuroMOMO data is the most robust available, the modelling of excess deaths does not take into consideration Ireland's 4% increase in adults aged over 65 from 2019 onwards. This gives rise to an underestimation of expected deaths and an overestimation of excess mortality.

Eurostat publishes monthly estimates of excess mortality that compares the number of people who died from any cause in a month with an historical baseline for that month from pre-pandemic years, 2016 to 2019. Since March 2020, Eurostat estimates that the EU27 has had a higher number of deaths than the 2016 to 2019 average in almost every month. Since early 2022, Ireland has followed a similar pattern, that is, the number of deaths in each month has been higher than the average number of deaths that occurred during the same month between 2016 and 2019. This method does not account for population growth or an ageing population, which significantly underestimates Ireland's expected deaths. As we know, the number of persons in Ireland aged 65 and over increased by 22%, more than double the 10% increase that occurred in the EU27 over the same period. Some 82% of all deaths which occurred in Ireland were among persons aged 65 and over. While both EuroMOMO and Eurostat are based on similar data on the number of deaths that occur, because of the different methodologies used to estimate expected deaths and excess deaths, these methods generate different estimates of excess mortality levels.

The CSO recently published an update of their frontier series publication, Measuring Mortality Using Public Data Sources 2019-2023, which includes an analysis of rip.iedeath notices and estimates of excess mortality. The CSO adopts a similar methodology to Eurostat to estimate excess deaths but, in the latest release, it uses a number of different baseline periods to illustrate how the estimation of excess deaths depends strongly on the baseline chosen and provides a range of estimated excess mortality rather than a single figure for each month.

An issue impacting analysis of mortality trends and estimates of excess mortality for Ireland is the time lag in death registration. As I outlined, in Ireland a legal period of three months is currently provided for the registration of a death. In the short term, the response to address the issue of this time lag has been the use of rip.ie data during the pandemic. While timely and with high coverage, it lacks key inputs, such as cause of death and age of deceased. Following a public consultation in 2021, work is under way by the Department of Social Protection, the General Register Office, the Department of Health, the Health Service Executive and the CSO to improve the timeliness and process of death registration in Ireland. This involves two main actions: the Department of Social Protection is progressing the civil registration (electronic registration) Bill 2023, which will legislate for more timely registration of deaths; and the development of technical solutions to allow notification and certification of deaths by hospital staff and GPs is under way within the HSE. The technical, procedural and legislative change required will, however, take some time to be implemented.

Considerable analysis is ongoing in relation to mortality trends in Ireland. In 2022, neoplasms, diseases of the circulatory system and external causes were the main causes of death among persons aged under 65 years. Diseases of the circulatory system, neoplasms and diseases of the respiratory system were the main causes of death among persons aged 65 years and over. Data for 2022 are provisional and based on date of registration of death.

The Health Protection Surveillance Centre will continue to participate in the EuroMOMO network to monitor trends in excess mortality during the upcoming winter. The EuroMOMO network is also working closely with the European Centre for Disease Prevention and Control, ECDC, to further develop and enhance its methodology to estimate excess mortality. The CSO is also continuing to examine methods for estimating excess deaths and mortality analysis. Internationally, the Department of Health is engaging closely with the OECD in its work on incorporating demographic change in its excess mortality estimates and the use of excess mortality as an indicator of the impact of climate change.

The Department of Health will continue to actively monitor and review all available data on mortality as these become available to gain a better insight on underlying mortality trends in Ireland and factors influencing these. The Department will also continue to work with all stakeholders to determine the most accurate estimates of mortality data in Ireland.

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