COVID-19 Deaths

National Statistical Institute

"Health and Justice Statistics" Department

Evelin Yordanova

Head of department

2, P. Volov Str.; 1038 Sofia, Bulgaria

[email protected]

+359 2 9857 459

Causes of death statistics is widely used as a basic source of information for health status international comparisons as well as for national analyses. The one-type data collection procedures, unified death certificate and WHO International Classification of Diseases are used in all European countries. Since 2005 the International Classification of Diseases - X Revision is used in Bulgaria. The requirements of ICD X are elaborated in COD statistical work in Bulgaria. According to Eurostat requirements since 2014 the harmonised 86 causes list is used for development of statistical tables as well as for analysis.

Data source on causes of death statistics is the medical death certificate. The form and the content of the document are determined by Ordinance № 42 of 8 December 2004 the Minister of Health, as part of the cause of death and other medical information is standardized in accordance with the recommendations of the World Health Organization (WHO).

The death certificate is filled in by the physician who recognized the death.

The coding of causes of death and stillbirth are carried out on a paper document by physicians working in Regional health inspections, specially trained to implement the requirements of the International Classification of Diseases - X revision and the Methodological instructions to Ordinance № 42 of 08.12.2004 of the Ministry of Health.

Data are broken down by sex, age groups, type of the settlement and cause of death (by chapters of ICD-10 or in accordance with the harmonized European Short List of 86 causes) at national level and by statistical regions and districts in accordance with the Nomenclature of territorial units for statistics in Bulgaria (NUTS 2 and NUTS 2).

Annual data are presented in numbers and per 100 000 of population.

• International Statistical Classification of Diseases and Related Health Problems, X rev.;
• Classification of Territorial Units for Statistical Purposes in Bulgaria (NUTS);
• Unified Classification of Administrative-Territorial and Territorial Units (UCATTU);
• European Shortlist - Harmonised 86 causes list, created by Eurostat in accordance with the standards of the World Health Organization and the International Statistical Classification of Diseases and Related Health Problems (ICD).

The deceased persons who have the present address in the Republic of Bulgaria are included.

In accordance with the requirements of WHO, statistical tables are elaborated based on the underlying cause of death, i.e. "the disease or injury which initiated the train of morbid events leading directly to death, or the circumstances of the accident or violence which produced the fatal injury".

Four-digit code of ICD - X rev. is used.

The cause of death frequency is the ratio between number of deaths by certain cause and annual average of the respective population. It is calculated per 100 000 of population.

Infant mortality rate is calculated per 1000 live born.

The statistical unit is the deceased person. The reporting unit is the physician who filled in the death certificate (certifier). The events are registered by following document:

• Death Certificate for deaths and
• Birth Certificate - for stillbirths.

The deceased persons who have a present address in the Republic of Bulgaria are included.

Covered by the territory of the Republic of Bulgaria. The regional data is according to the administrative-territorial division of the country as of 31.12. of the reference year.

By 1994 - only published data.

1995 - 2004 - the data are available on request.

2005 - 2023 - the data are available on the website www.nsi.bg  

Not applicable.

Data source for deaths and stillbirths are forms of National Civil Registration System (NCRS). The events are registered by following document:

• Death Certificate for death events;
• Birth Certificate - for stillbirths.

Annually

1. Certification

Description of the certification process and the validation process

Data source on causes of death statistics is the medical certificate of death. The form and content of the document are determined by the Ordinance № 42 of 8 December 2004 the Minister of Health, as the part of the causes of death and other medical information is standardized in accordance with the recommendations of the World Health Organization (WHO).

The death certificate is filled in by the physician who recognized the death in accordance with the Amendment and supplement of Ordinance № 14/2004 of the Ministry of Health on medical criteria and procedures for the identifying death, publ., SG 41 of 21.05.2019. The national legislation determines in details all the procedures and medical criteria needed in order to identify the person as deceased 

 How  are the certification errors assessed? 

Supervision and control of the certification process is carried out by experts in Regional health inspections occasionally or ad hoc on a specific issue.

Is training in certification obligatory in your country?

The training in certification is part of the medical education.

2. Coding

Did you use any form of automated coding? No

Underlying cause of death selection and modification - only manual selection of underlying cause is applied.

Information available in the national COD database - only information on the underlying cause is stored in the national COD database. Multiple cases are not available.

Stillbirths and Neonates: Do you have a different death certificate or do you code these data differently from other deaths? If yes, how?

Stillbirths - Data source for stillbirths is the certificate of birth. The certificate is completed in health establishment and in case of stillbirth one copy is submitted to the Regional health inspections. Coding of causes of stillbirth (as well as deaths) is performed by doctors working in Regional health inspections, specially trained for this purpose.

Neonates - The neonatal deaths are coded as all other deaths.

1. Coding

The coding of underlying cause of death is carried out by physicians working in Regional Health Inspections, specially trained to implement the requirements of the International Classification of Diseases - X revision.

Physician who codes the cause of death must review the medical information in the death certificate, and in cases it is not filled in correctly, he is obliged to contact with the physician, who has issued a death certificate for further specifications.

After coding the documents are submitted to the Regional Statistical Offices for entering the information. The data is processed and stored in IS "Demography".

Data validation is performed:

• At data transmission – preliminary checking and processing, the proper application of the criterion for length of stay of 12 months.
• At the data processing stage - criteria for doubling, correctness, validation rules for each record’s characteristic incl. potential inconsistency in the death certificate or error due to mistake when filling the deaths certificates. In case of inconsistencies or errors, the physician who codes and/ or certifier should be contacted. 

Description of the outcome of the error detection procedures in place
In case of inconsistencies or errors, the certifier should be contacted. 

Is coding carried out at a central level?
The coding is carried out in the Regional Health Inspections. The Regional Health Inspections implement and organize the government health policy within the territory of administrative regions. There are 28 Regional Healthcare Inspections in the country.

Is coding performed by a certifier?

No. The coding of underlying cause of death is carried out by physicians working in Regional Health Inspections, specially trained to implement the requirements of the International Classification of Diseases - X revision.

Are double coding exercises performed  (if yes, please indicate the rate of codification errors for uderlying cause of death/if not give an estimate of the rate of codification errors)?

No.

2. Validation process

Data validation is performed at three stages:

• At data transmission – preliminary checking and processing, the proper application of the criterion for length of stay of 12 months.
• At the data processing stage - criteria for doubling, correctness, validation rules for each record’s characteristic.
• Before data release - checking the frequencies of separate variables, consistency of table and cross-tabulations.

What are the criteria (external source, local registers, …) used for the validation of the coverage?

Data source for all demographic events is the National civil registration system. Events information is obtained as an electronic file. Causes of death and stillbirth are coded on a paper documents, a copy of which is also obtained. In case of stillbirth as well as death of a child up to 168 hours of his/her birth a certificate for perinatal death is filled in and send to the Regional health inspections. The last is used to verify data on perinatal mortality.

The data is processed and stored in IS "Demography".

Not applicable.

Strict implementation of the WHO requirements and the rules and instructions for certification and coding according to ICD - X rev.

Annual logical control of data quality in accordance with ICD - X rev.

Implementation of the recommendations of Eurostat for quality control of the data.

Integrated quality and security management system has been implemented in accordance with the requirements of BDS EN ISO 9001: 2015 and BDS EN ISO 27001: 2017. The certificate fully meets all international requirements and guarantees the quality of the processes and information security of the entire statistical and information infrastructure of the NSI, both at national and regional levels.

Integrated quality and security management system has been implemented in accordance with the requirements of BDS EN ISO 9001: 2015 and BDS EN ISO 27001: 2017. The certificate fully meets all international requirements and guarantees the quality of the processes and information security of the entire statistical and information infrastructure of the NSI, both at national and regional levels.

Data on causes of death are provided annually to Eurostat and World Health Organization (WHO) in strict compliance with the prescribed terms and forms of presentation of the data. In the framework of regular annual questionnaires data are also provided to other European and international organizations - UNESCO, UNICEF, etc. Users of health information at national and regional level are the National Assembly of the Republic of Bulgaria, the executive and local authorities, National Health Insurance Fund. The data are provided annually to the National Centre for Public Health and Analysis at the Ministry of Health, Ministry of Health and its territorial units - Regional Health Inspections, whose functions are to implement and organize the government health policy at national and regional level.

Upon request data is provided to research institutes, universities, NGOs and other users.

Not applicable.

For the public dissemination (the website) data on causes of death are presented by chapters of ICD-10 and according to the Eurostat harmonised 86 causes list and in accordance with the standards of the World Health Organization and the International Statistical Classification of Diseases and Related Health Problems (ICD). Since 2020 in accordance with the WHO updates as well as  Ministry of Health instructions and guidelines Chapter 22 Codes for special purposes (U00-U85),  of which COVID-19 (U07.1-U07.2) is included in the tables. Detailed tables on COVID-19 (U07.1-U07.2) deaths in Bulgaria have been also published.

In accordance with the ICD definitions:

U07.1 COVID-19,  virus identified - confirmed by laboratory testing irrespective of severity of clinical signs or symptoms;

U07.2 COVID-19,  virus not identified - diagnosed clinically or epidemiologically but laboratory testing is inconclusive or not available.

Data are presented by sex, 5-year age groups, type of the settlement and cause of death at national level and by statistical regions and districts in accordance with the Nomenclature of territorial units for statistics in Bulgaria (NUTS 2 and NUTS 2).

Not applicable.

Exhaustive survey.

Not applicable.

Not applicable.

Not applicable.

Administrative data sources are used for production of official statistics. Data files are provided to NSI containing information on demographic events - births, deaths, marriages, divorces, change of address in the country, international migration. Computer files are received from the Unified System for Civil registration and Administrative Service of Population.

Registration is done at the moment of death/ birth and the number is calculated as of 31.12 of the reference year. Data collection is exhaustively for all deaths/ stillbirths registered during the year.

The events are registered at their occurrence according to the usual residence of the person and they form the respective periodical aggregate for a fixed time. This specific time for the current demographic statistics as well as for health statistics is a calendar year.

Data are processed, edited and validated through the Information System Demography, respecting the settled in advance system and logic criteria. Data on demographic events is checked and controlled before to be loaded in the IS "Demography".

For successful processing, the initial notification should meet the system rules on validation and control. The processed results are validated in respect the consistency of a single table and between the tables.

Records linkage is done based on Identification Number of the persons subject of a demographic event.

Data validation is performed at three stages:

• At data transmission – preliminary checking and processing, the proper application of the criterion for length of stay of 12 months.
• At the data processing stage - criteria for doubling, correctness, validation rules for each record’s characteristic.
• Before data release - checking the frequencies of separate variables, consistency of table and cross-tabulations.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

Not applicable.

The revision of data is possible after validation procedure in accordance with the Regulation (EU) 328/2011 requirements. In addition, revision is possible when have a change in statistical regions (NUTS 2).

See pervious position.

Not applicable.

T+6 months

Data are disseminated according to the Release Calendar presenting the results of the statistical surveys carried out by the National Statistical Institute.

The data are comparable for all territorial regions in the country.

For international comparison the following has to be taken into account - The comparability of the data across different countries is limited by the fact that the revision of classification used to collect information on underlying cause of death may be different. Furthermore, not all countries apply the recommended WHO's updates. 

The coverage of residents dying abroad or non-residents dying in the reporting country can also affect the comparability among countries.

Not applicable.

The time series for deaths by causes are comparable since 2005 (according to ICD - X rev).

Until 2004 ICD - IX rev. was used.

The total number of cause of death (stillbirths by cause) are equal to the number of deaths (stillbirths) in the theme "Population".

Not applicable.

Not applicable.

Not applicable.

Not applicable.

• Health Services;
• Statistical yearbook;
• Population and Demographic Processes.

Data on Deaths by causes and mortality by causes are available to all users of the NSI website under the heading Health - Deaths by causes and mortality by causes: https://www.nsi.bg/en/node/5614;

Online database of Eurostat.

Not applicable.

Anonymised individual data can be provide for scientific and research purposes, and for individual request according to the Rules for the provision of anonymised individual data for scientific and research purposes.

All data on causes of deaths are stored in a database "Demography". Access is strictly regulated in accordance with the rules on protection of personal data and protection of statistical secrecy.

Information service on request, according to the Rules for the dissemination of statistical products and services in NSI.

Not applicable.

• Methodological notes: https://www.nsi.bg/sites/default/files/files/metadata/Zdr_6_Methodology_EN.pdf;
• International Statistical Classification of Diseases and Related Health Problems (ICD) - X rev.
• WHO and Ministry of Health instructions and guidelines. 

100%

The quality of information on causes of deaths and mortality by causes are mainly determined by the information filled in by the physician as well as by the implemented rules for the selection and coding of the underlying cause of death.

Not applicable.

• Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society;
• Law on Statistics;
• Law on Personal Data Protection.

The level of detailing of the causes of death and preparation of statistics table data are in accordance with the recommendations of the World Health Organization.