Evolution of Pathology Patterns in Persons Who Died From COVID-19 in Italy: A National Study Based on Death Certificates

Abstract

Background: In Italy, during the first epidemic wave of 2020, the peak of coronavirus disease 2019 (COVID-19) mortality was reached at the end of March. Afterward, a progressive reduction was observed until much lower figures were reached during the summer, resulting from the contained circulation of SARS-CoV-2. This study aimed to determine if and how the pathological patterns of the individuals deceased from COVID-19 changed during the phases of epidemic waves in terms of: (i) main cause of death, (ii) comorbidities, and (iii) complications related to death.Methods: Death certificates of persons who died and tested positive for SARS-CoV-2, provided by the National Surveillance system, were coded according to ICD rev10. Deaths due to COVID-19 were defined as those in which COVID-19 was the underlying cause of death.Results: The percentage of COVID-19 deaths varied over time. It decreased in the downward phase of the epidemic curve (76.6 vs. 88.7%). In February–April 2020, hypertensive heart disease was mentioned as a comorbidity in 18.5% of death certificates, followed by diabetes (15.9% of cases), ischemic heart disease (13.1%), and neoplasms (12.1%). In May–September, the most frequent comorbidity was neoplasms (17.3% of cases), followed by hypertensive heart disease (14.9%), diabetes (14.8%), and dementia/Alzheimer's disease (11.9%). The most mentioned complications in both periods were pneumonia and respiratory failure with a frequency far higher than any other condition (78.4% in February–April 2020 and 63.7% in May–September 2020).Discussion: The age of patients dying from COVID-19 and their disease burden increased in the May–September 2020 period. A more serious disease burden was observed in this period, with a significantly higher frequency of chronic pathologies. Our study suggests better control of the virus' lethality in the second phase of the epidemic, when the health system was less burdened. Moreover, COVID-19 care protocols had been created in hospitals, and knowledge about the diagnosis and treatment of COVID-19 had improved, potentially leading to more accurate diagnosis and better treatment. All these factors may have improved survival in patients with COVID-19 and led to a shift in mortality to older, more vulnerable, and complex patients.

Variation in Cause-Specific Mortality Rates in Italy during the First Wave of the COVID-19 Pandemic: A Study Based on Nationwide Data

“…Italy was one of the countries more severely hit by the first COVID-19 pandemic wave in early 2020. So far, in Italy, mortality studies have focused on comorbidities reported in small groups of death certificates of patients with COVID-19 [ 12 , 13 ] or on broad categories of CoDs in small geographical areas [ 14 , 15 ]. The availability of data from the national CoD register represents a unique opportunity for a full analysis of the impact of the pandemic on the most common CoDs.…”

Analysis of Multiple Causes of Death: A Review of Methods and Practices

“…114 While we identified only one COVIDrelated article (due to the timing of our database search), multiple-cause methods have since been applied to ascertain associations between contributing conditions and complications, assess changes in the pathological patterns, and identify noteworthy sociodemographic variation in COVID-related deaths, [115][116][117][118] leading in some circumstances to improved survival. 119 Importantly, the recent emergence of COVID-19 as a leading underlying cause 120 may substantially alter proportional mortality from other underlying causes. As such future analyses of multiple causes will be necessary for monitoring trends in COVID-related mortality as well as the impact of COVID-19 on other causes of death.…”

Analysis of multiple causes of death: a review of methods and practices

“…110 While we identified only one COVID-related article (due to the timing of our database search), MC methods were since applied to ascertain associations between contributing conditions and complications, assess changes in the pathological patterns, and identify significant sociodemographic variation in COVID-related deaths, [111][112][113][114] leading in some circumstances to improved survival. 115 Importantly, the recent emergence of COVID-19 as a leading UC 116 may significantly alter proportional mortality from other UCs. As such future analyses of multiple causes will be necessary for monitoring trends in COVID-related mortality as well as the impact of COVID-19 on other causes of death.…”