Sampling strategy, characteristics and representativeness of the InGef research database.

Area of Science:

• Health services research
• Epidemiology
• Biostatistics

Background:

• The German InGef research database provides longitudinal claims data for approximately 8.8 million individuals.
• Establishing the representativeness of healthcare databases is crucial for reliable epidemiological studies.

Purpose of the Study:

• To detail the sampling strategy for the InGef sample database.
• To assess the characteristics and external validity of a representative sample of 4 million individuals from the InGef database.
• To compare the sample database with national reference data for validation.

Main Methods:

• Retrospective cohort study utilizing anonymized claims data from 2019.
• A sample of 4 million individuals was drawn from the InGef database, aiming for representativeness in age, sex, and region.
• Analysis included demographic data, hospitalization rates, mortality rates, and drug prescription rates, compared against national statistics.

Main Results:

• The InGef sample closely mirrored the German population in sex distribution (50.8% vs 50.7% women) and mean age (44.1 vs 43.9 years).
• A slightly lower proportion of individuals from eastern Germany were in the sample (16.5% vs 19.5%).
• Hospitalization and mortality rates showed good agreement with national data; prescription rates for top drug classes were marginally higher.

Conclusions:

• The InGef sample database demonstrates strong overall concordance with the German population.
• The database is a valid and representative resource for studying morbidity, mortality, and drug usage in Germany.
• Findings support the utility of the InGef sample database for health research and policy.