May 28, 2024

Public workspaceCalculating the Cause of Death Association Indicator and the Contributing Cause of Death Association Indicator in Mortality Analysis

  • 1University of Warsaw
Open access
Protocol CitationAgnieszka Fihel, Anna Janicka 2024. Calculating the Cause of Death Association Indicator and the Contributing Cause of Death Association Indicator in Mortality Analysis. protocols.io https://dx.doi.org/10.17504/protocols.io.e6nvw1dd7lmk/v1
Manuscript citation:
Fihel et al. 2024, submitted to PlosOne.
License: This is an open access protocol distributed under the terms of the Creative Commons Attribution License,  which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited
Protocol status: Working
We use this protocol and it's working
Created: May 23, 2024
Last Modified: May 28, 2024
Protocol Integer ID: 100386
Keywords: COVID-19, multiple causes of death, causes of death, mortality, death certificate, comorbidity, Cause of Death Association Indicator
Funders Acknowledgement:
University of Warsaw
Grant ID: the Priority Research Area V of the "Excellence Initiative – Research University" programme
Abstract
The protocol describes the input data and the method used to calculate the Cause of Death Association Indicators and the Contributing Cause of Death Association Indicators in the analysis of mortality. These indicators measure the strength and statistical significance of associations between causes of death jointly reported on death certificates. The protocol applies to the study of COVID-19-related deaths in Central Europe.
Attachments
Materials
Appendix 1: List of causes of death
Input data
Input data
The input data consists of death counts aggregated by country, year, sex, age group (30-59 and 60+), the underlying cause of death u, and cause c reported in any section of the death certificate other than the underlying cause of death. In practice, causes u and c refer to groups of causes of death, aggregated according to the grouping presented in Attachment 1.

Example of an aggregate: deaths of women in Poland in 2021, at the age of 60 and over, due to COVID-19 (ICD-10 codes: from U07.1 to U10.9) as the underlying cause of death and well-defined infectious and parasitic diseases (ICD-10 codes: A00-B99 excl. A40-A41, A48-A49, B34, B97-B99) mentioned in a section other than the underlying cause of death.
Cause of Death Association Indicator
Cause of Death Association Indicator
The CDA indicator was originally proposed in:

Désesquelles A, Salvatore MA, Frova L, Pace M, Pappagallo M, Meslé F, et al. Revisiting the mortality of France and Italy with the multiple-cause-of-death approach. Demographic Research. 2010;23:771–806. 
The formula is as follows:
Capture d’écran 2024-05-23 à 19.13.30.png

where stands for the number of deaths, subscript u refers to a given underlying cause of death, subscript c refers to a given comorbidity or complication, and subscript x stands for age, and
Capture d’écran 2024-05-23 à 19.09.46.png

stands for the average number of deaths at age x in all countries and years of the analysis. This average is used to compare CDAIs between countries where the distribution of deaths by age is different.
In this study, cause u in CDAIs was COVID-19.

Data used to calculate CDAIs for Poland can be made available upon request.
95% confidence intervals for CDAIs were calculated under the assumption that the observed number of deaths follows a Poisson distribution, with the variance approximated by the number of deaths.

obraz.png

A CDAI significantly higher than 100 indicates that complication or comorbidity is more common than expected in deaths due to UCoD u.
Contributing Cause of Death Association Indicator (CCDAI)
Contributing Cause of Death Association Indicator (CCDAI)
The CCDA indicator was originally proposed in: Fihel et. al. 2024, submitted to PlosOne.
The formula is as follows:

Capture d’écran 2024-05-23 à 19.24.32.png

where stands for the number of deaths, subscript u refers to a given underlying cause of death, subscript c refers to a given comorbidity (in this study: COVID-19), subscript x stands for age and 
Capture d’écran 2024-05-23 à 19.25.04.png

is the average number of deaths at age x with comorbidity c (COVID-19). As in the case of CDAIs, the average count of deaths (with comorbidity c) is used to standardise the indicators.
Data used to calculate CCDAIs for Poland can be made available upon request.
95% confidence intervals for CCDAIs were calculated under the assumption that the observed number of deaths follows a Poisson distribution, with the variance approximated by the number of deaths.

obraz.png

A CCDAI significantly higher than 100 indicates that underlying cause u is more common than expected in deaths with comorbidity c.
Protocol references
Désesquelles A, Salvatore MA, Frova L, Pace M, Pappagallo M, Meslé F, et al. Revisiting the mortality of France and Italy with the multiple-cause-of-death approach. Demographic Research. 2010;23:771–806.