Definition

The indicator HbA1c measurement is defined as the proportion of people with known type 2 diabetes who had their HbA1c levels determined in the past 12 months.

Operationalisation

Self-report on the following question for people with known diabetes:

"When was the last time that the HbA1c, i.e. hemoglobin A1c, was measured?"

Response options (For over 12 months, the figure was given in years):

• How many months ago: |__|__|
• How many years ago: |__|__|
• never
• do not know
• not sepcified

Reference population

People with known diabetes in the German-speaking resident population of Germany, aged 45 years and over.

Data source

Nationwide RKI survey GEDA 2021/2022-Diabetes based on a special screening process that focused on the target group ‘people with known diabetes aged 18 years’ (GEDA 2021/2022-Diabetes).

Number of cases

• GEDA 2021/2022-Diabetes: n = 1,503

For the indicator HbA1c measurement, data were collected completely among people with known type 2 diabetes aged 45 years and over:

• GEDA 2021/2022-Diabetes: n = 1,448

People with type 1 diabetes and women with exclusively gestational diabetes were excluded.

Calculation

• Description: For the indicator, the figures for total, women and men are provided and are stratified by age group, residential area and education as far as the number of cases available for the figure is ≥ 5 and the statistical uncertainty in the estimate of the indicator is not considered too large (a coefficient variation ≤ 33.5%).
• Stratification: The geographical classification of the residence of the participating person was carried out by region (east = former East Germany, including all of Berlin; west = former West Germany, not including West Berlin). Educational status was determined using the CASMIN index, which takes information on both school and vocational training into account and allows a categorisation into a low, medium and high education group.
• Weighting: A weighting factor was used to correct for deviations from the underlying reference population due to different participation rates or sampling probabilities. It adjusts the surveys sample to the population structure of the reference population in terms of sex, age and education as of 31 December 2019. The distribution structure of people diagnosed with diabetes from the nationwide RKI survey GEDA 2019/2020-EHIS were used to calculate the weighting factor, since data from the population statistics provided by the Federal Statistical Office do not allow conclusions about people diagnosed with diabetes in the German-speaking resident population aged 18 years and over.

Data quality

The RKI survey GEDA 2021/2022 provides representative results about people with known diabetes from the German-speaking resident population of Germany aged 18 years and over. As with all population-based studies, it can be assumed that the study underrepresents people with serious illnesses and those currently in institutions. In addition, the survey data is based on information provided by the respondents. Comparisons of findings to previous RKI surveys are limited due to differences in methodology.