Data sources

These data sources can be divided into the following groups:

Primary data

The population-representative RKI health surveys are essential data sources for diabetes surveillance. Information from the following surveys is currently used to populate the indicators:

• German National Health Interview and Examination Survey 1998, GNHIES98
• German Health Interview and Examination Survey for Adults, DEGS1
• German Health Update, GEDA (GSTel03, GEDA 2009 – 2012, GEDA 2014/15-EHIS)
• Add-on survey ‘Disease knowledge and information needs – Diabetes mellitus (2017)’

Examples of what can be shown using data from RKI health surveys:

• Test results (such as blood pressure, HbA1c, cholesterol)
• Behavioural risk factors (such as physical activity and nutrition)
• Subjective health (such as health-related quality of life, patient satisfaction, depressive symptoms)
• Identification of particularly at-risk population groups depending on social status

Limitations of RKI health surveys:

• The relatively long intervals between data collection. This particularly applies to surveys that include an examination part
• The limited representativeness of the results when it comes to certain population groups such as seriously ill or very old people, those living in nursing homes and people without the necessary German language skills to participate

Secondary data

Secondary data are data that were originally collected for another purpose or in order to answer a different research question. They represent another important data source for diabetes surveillance. The following bodies of data are used to populate the indicators:

• Routine claims and billing data from statutory health insurance (SHI), also known as DaTraV data
• Diagnosis-related groups statistics (DRG statistics) from the Federal Statistical Office 
• Diagnoses leading to a disability pension from German Pension Insurance
• Quality assurance data on obstetrics based on perinatal statistics from the federal states
• Documentation data from the Disease Management Programmes (DMP)

These data sources enable, for example, the following indicators to be presented at regular intervals and by state:

• The prevalence, incidence and mortality of documented diabetes
• The complications of diabetes and ambulatory care-sensitive hospitalisations
• Disability pension provision following a diagnosis of diabetes
• The indicators of gestational diabetes
• DMP participation rate and DMP quality target achievement

Limitations of secondary data sources:

• The quality of the data recorded for claims and billing purposes depends on local documentary practices. This affects the completeness and validity of the available data.
• Data from individual statutory health insurers are not representative of all statutory health insurers and do not contain information about people with private insurance.

Further data sources

Diabetes surveillance also uses data from the nationwide diabetes patient documentation (DPV) and from regional epidemiological diabetes registers. The data from these registers play an important role, particularly in the case of the less common types of diabetes such as type 1 diabetes, or type 2 diabetes in children and adolescents. In order to calculate the figures for some indicators, information from official statistics, such as cause of death statistics supplied by the Federal Statistical Office, are also required.