All-cause mortality rates show full consequences of COVID-19

A considerable underestimation of the actual number of deaths from the novel coronavirus disease (COVID-19) appears to prevail in some regions, according to an Italian study, which also suggests that all-cause mortality be considered to completely understand the full implications of the disease.

“[W]e believe data on all-cause mortality should be considered along with traditionally reported measures as an important metric to evaluate and compare the consequences of the COVID-19 pandemic within and between settings,” the researchers said.

This descriptive study included residents of Nembro in Lombardy, Italy. The following outcomes were measured: monthly all-cause mortality between January 2012 and April 2020, number of confirmed deaths from COVID-19 to 11 April 2020, and weekly absolute number of deaths between 1 January and 4 April across recent years by age group and sex.

As of 1 January 2020, Nembro had a total of 11,505 residents. Between January 2012 and February 2020, the monthly all-cause mortality fluctuated around 10 per 1,000 person-years, with a maximum of 21.5 per 1,000 person-years. [BMJ 2020;369:m1835]

However, the monthly all-cause mortality in March 2020 reached a record high of 154.4 per 1,000 person-years. The number of deaths among older people (aged ≥65 years), particularly men, was the main driver of such increase in mortality. This rate decreased for the first 11 days in April to 23.0 per 1,000 person-years.

“Although all-cause mortality can only be interpreted as an approximation of the health status of the population under study, it is more often systematically collected under high quality standards, relies on universally accepted classification, and is not influenced by testing strategies or shortages of tests,” the researchers said.

Of interest, only 85 confirmed deaths from COVID-19 were recorded in Nembro from the outbreak onset until 11 April 2020. This corresponded to about half of the 166 deaths from all causes observed in that period.

These findings support those of a large study by the Instituto di studi e ricerche Carlo Cattaneo, which compared the overall number of deaths between 21 February 2020 and 21 March 2020 with the number of deaths in the same period averaged over the previous 5 years in more than 1,000 cities in Italy. [www.cattaneo.org/2020/04/01/gli-effetti-del-covid-19-sulla-mortalita/]

The Cattaneo study suggested that the number of deaths attributable to COVID-19 in Italy would still be twice as high as the number of confirmed deaths from the disease reported by the authorities even under the best-case scenario.

“This study sheds light on the scale of the problem—that many deaths are erroneously not being attributed to COVID-19 and that many of those who die outside of a hospital and have the disease are not being tested,” the researchers noted.

They stressed further that the consequences of a pandemic are not limited to deaths related to COVID-19 but rather contribute indirectly to potentially avoidable deaths due to extreme triage of limited resources in crisis situations. [BMC Med2020;18:57]