Methods for Ensuring High Quality of Coding of Cause of Death. The Mortality Register to Follow Southern Urals Populations Exposed to Radiation.

BACKGROUND: To follow up populations exposed to several radiation accidents in the Southern Urals, a cause-of-death registry was established at the Urals Center capturing deaths in the Chelyabinsk, Kurgan and Sverdlovsk region since 1950. OBJECTIVES: When registering deaths over such a long time period, quality measures need to be in place to maintain quality and reduce the impact of individual coders as well as quality changes in death certificates. METHODS: To ensure the uniformity of coding, a method for semi-automatic coding was developed, which is described here. Briefly, the method is based on a dynamic thesaurus, database-supported coding and parallel coding by two different individuals. RESULTS: A comparison of the proposed method for organizing the coding process with the common procedure of coding showed good agreement, with, at the end of the coding process, 70 - 90% agreement for the three-digit ICD -9 rubrics. CONCLUSIONS: The semi-automatic method ensures a sufficiently high quality of coding by at the same time providing an opportunity to reduce the labor intensity inherent in the creation of large-volume cause-of-death registries.

Mayak workers study cohort. An inter-institutional comparison of causes of death in the cause-of-death register of Ozyorsk in the Russian Federation.

BACKGROUND: The cause-of-death register at the Southern Urals Biophysics Institute (SUBI), Ozyorsk, Russia, was established to document the number and causes of deaths in the Mayak workers cohort, which includes all persons (N = 22,377) employed at Mayak nuclear facility between 1948 and 1982. Most workers were occupationally exposed to high doses of ionizing radiation and have been shown to have increased risks of various chronic diseases including cancer. OBJECTIVES: To investigate the quality of cause of death coding in the SUBI register. METHODS: A random sample of 246 deaths (~1% of the total) was coded independently at the SUBI and the Danish Cancer Society using the International Classification of Diseases 9 (ICD-9). Proportions of matching codes were calculated. RESULTS: Overall, 233 deaths (95%) were identically classified using the ICD-9 main category matching. Excluding mismatches that were considered to be incorrectly coded during validation, the validity of the register increased to 98%. Using the specific ICD-9 first three-digit matching, 182 deaths were identically coded (74%) and the respective validity of the register was 85%. There were also some non-resolvable discrepancies demonstrating limitations of assigning one code for each death or using language-adapted ICD-9 version. CONCLUSIONS: This validation study was an important quality check of a register used for mortality follow-up in a highly influential epidemiological study on radiation-related health effects. The results of the inter-institutional comparison were generally favourable; however, since the comparison revealed individual mismatches and some systematically differing coding practices, it is essential to repeat it on a regular basis in order to maintain a high quality.

Cause-of-death registers in radiation-contaminated areas of the Russian Federation and Kazakhstan.

Since the early 1990s, information on radiation-exposed populations other than those exposed from the Chernobyl accident in 1986 has become increasingly available for international scientific research. It is essential to understand how the cohorts of exposed populations have been defined and what mechanisms can be used to study their health outcomes. Different international scientific research collaborations currently investigate four population groups chronically exposed to ionizing radiation during the late 1940s and early 1950s in the Russian Federation and in Kazakhstan. In this framework, collaborations have been established to develop cause-of-death registers in each of these four areas for future mortality follow-up purposes with the aim of studying the health effects of ionizing radiation. The emphasis of this effort is on assessing the information sources available, the mechanisms of data collection and coding, and the data quality and completeness of the information collected. One of the major challenges is the harmonization of all these aspects between the four different centers to the extent possible, taking into account that much of the actual data has been collected over many decades.

Factors effecting the morbidity in populations living in the vicinity of atomic industry plants.

In order to examine the effects of radiation, chemicals, and social factors on the incidence of different diseases in the population living in the vicinity of atomic industry facilities, the site of the Production Association 'Mayak' has been selected for detailed analyses. Diseases under study were morbidity among newborns including congenital anomalies, diseases of respiratory organs, and cancer. Using a regression model, no statistically significant correlation was found between incidence and radiation exposure.