[Mortality follow-up of the German Health Interview and Examination Survey for Adults (DEGS) : methods and first results]. / Mortalitäts-Follow-up der Studie zur Gesundheit Erwachsener in Deutschland (DEGS) : Methodik und erste Ergebnisse.

OBJECTIVES: Within the framework of the German Health Interview and Examination Survey for Adults (DEGS), the Robert Koch Institute (RKI) conducted a nationwide mortality follow-up study. As there is no national mortality register in Germany, mortality and causes of death were investigated individually and under observance of state-specific data protection conditions. METHODS: The German Health Interview and Examination Survey 1998 (GNHIES98) provided the database including 7,124 participants aged 18-79 years. A total of 6,979 participants of GNHIES98 (98 %) who consented to be re-contacted were invited between October 2008 and October 2011 to also participate in the first data collection wave of DEGS (DEGS1). In this context, the vital status and the causes of death for deceased participants were assessed. Age- and sex-specific probabilities of survival and death rates were calculated and grouped by main causes of death according to ICD-10 groups. RESULTS: A total of 671 individuals (285 women, 386 men) died between the two survey contacts. For all deceased persons the date of death and for 539 (80.3 %) the causes of death could be determined. With a median follow-up time of 12.0 years, 8,0742.5 person years were available for survival analysis. The crude overall death rate amounted to 8.3 per 1,000 persons-years (women: 7.2; men: 9.5). Among 539 persons with available information on causes of death, 209 (38.8 %) were attributable to cardiovascular diseases, 188 (34.9 %) to cancer, 135 (25.0 %) to other causes, and seven (1.3 %) could not be unambiguously assigned. CONCLUSIONS: A mortality follow-up was successfully integrated in the longitudinal component of DEGS as part of the national health monitoring at the RKI. Death rates and cause-specific mortality in relation to highly prevalent chronic diseases and risk factors provide essential information for assessing the potential of prevention and quality of care among adults in Germany. This requires a regular and complete conduction of mortality follow-ups.

[Possibilites and limitations of retrospective research on cause of death within the framework of a nationwide epidemiological study]. / Möglichkeiten und Grenzen retrospektiver Todesursachenrecherchen im Rahmen bundesweiter epidemiologischer Studien.

Cause-specific mortality is an important endpoint in longitudinal epidemiological studies to research causal health links and carry out individual process analyses. As in Germany no national mortality register exists, state-specific data-protection conditions for and approaches to cause of death studies were researched and tested within the framework of a pilot project. The database was provided by a sample of deceased study participants from the 1998 nationwide health survey. Under the given conditions, cause of death research in a nationwide epidemiological study is possible in principle, but requires a great deal of time and effort. In Rhineland-Palatinate research needs to be carried out in a timely manner as the health authorities' retention period for death certificates is limited to minimum of 5 years. In Berlin the research situation is particularly difficult as, while the death certificates are held 3 years by the statistics bureau, this department cannot release any pseudonymous data. In Berlin it is possible to research the cause of death for some of the deceased through the doctors and hospitals that issued the death certificates and through the GKR Berlin-Brandenburg (in keeping with the special data protection measures of the cancer registry). In North Rhine Westphalia the written consent obtained during people's lifetimes, including an explicit release from medical confidentiality, is required to carry out cause of death research. In all other German states exceptions are possible, in all cases requiring the consent of the state's data protection commissioners. The results of the pilot project underline the need for a national mortality register. Until this is established the approach used in the pilot study can be used and, working together with the state and national data protection authorities and with the highest national health authorities, can be further optimized in order to avoid losing data and to use resources efficiently.