Prevalence of type 2 diabetes from 2011 to 2023 by regional socioeconomic deprivation in Germany: an ecological study

Type 2 diabetes prevalence is increasing globally and is unequally distributed across socioeconomic groups. In Germany, little is known about how these socioeconomic inequalities have developed over time. Therefore, we aimed to estimate the age- and sex-specific prevalence of type 2 diabetes in Germany from 2011 to 2023 and assess related temporal trends in socioeconomic inequality. We used nationwide claims data (N ~ 70 million persons per year) from the German statutory health insurance, aggregated at the county level and linked them to the German Index of Socioeconomic Deprivation (GISD), an area-based measure of deprivation based on education, occupation, and income. We identified prevalent type 2 diabetes cases using ICD-10 codes E11, E12, E13, and E14. Log-binomial regression was used to estimate prevalence ratios for the association between GISD quintiles and type 2 diabetes prevalence, with temporal trends assessed through the four-way interaction between age, sex, GISD, and calendar year. Crude type 2 diabetes prevalence increased from 9.00% (95% confidence interval: 8.99–9.01) in 2011 to 9.60% (9.59–9.61) in 2023, while age-standardised prevalence showed a smaller increase, from 9.00 (8.99-9.00) in 2011 to 9.35% (9.34–9.35) in 2023. A clear socioeconomic gradient emerged, with the highest prevalence of 11.80% (11.78–11.82) in 2023 in the most deprived regions (quintile 5), compared to 8.00% (7.99–8.01) in the least deprived regions (quintile 1). Prevalence was consistently higher in men than women, but the socioeconomic gradient was more pronounced among women (prevalence ratio 2023 women 1.29 (1.23–1.35), men 1.22 (1.17–1.26)). Our findings highlight persistent socioeconomic disparities in type 2 diabetes prevalence, especially among women. Further research is needed to explore the mechanisms underlying these disparities and to evaluate targeted interventions for high-risk populations.