Definition

The indicator hypertension is defined as the proportion of people with current high blood pressure in people with known type 2 diabetes in comparison to that in people without known diabetes. High blood pressure is defined as hypertonic blood pressure (systolic ≥ 140 or diastolic ≥ 90 mm Hg) or cases where antihypertensive medication is being taken for known hypertension.

Operationalisation

The following information was considered during the analyses:

• The mean systolic and diastolic pressure was determined auscultatorically in GNHIES98 using a classic blood pressure monitor and oscillometrically in DEGS1 with an automatic blood pressure monitor (Datascope Accutorr Plus). The values taken for GNHIES98 and DEGS1 were cross-calibrated for comparability.

Hypertension is defined as:

• systolic blood pressure ≥ 140 mm Hg or
• diastolic blood pressure ≥ 90 mm Hg

or

• Known hypertension: self-reported hypertension ever diagnosed by a doctor during a computer-assisted medical interview based on the question:

(GNHIES98):

• “Have you ever been diagnosed by a doctor with one of the following illnesses or health disorders?” high blood pressure, hypertension

  • Yes
  • No

(DEGS1):

• "Have you ever been diagnosed by a doctor as having high or high blood pressure?"

  • Yes
  • No
  • Don’t know

and

• Documentation of the intake of antihypertensive drugs within the last 7 days among people with known hypertension by the medication capturing programme AmEDa (Arzneimittel Erfassungs-Datenbank) using the following ATC codes C03 (Diuretics), C07 (Beta blocking agents), C08 (Calcium channel blockers), C09 (Agents acting on the renin–angiotensin system), C02 (Antihypertensives).

Indicators depicted separately for people with known type 2 diabetes and without known diabetes.

In order to focus on known type 2 diabetes, those who may have type 1 diabetes were identified and excluded from among participants with known diabetes using an algorithm (age at diabetes diagnosis <30 years AND insulin treatment immediately after diagnosis AND current insulin treatment).

Reference population

Resident population in Germany with known type 2 diabetes and without known diabetes, aged 45 to 79 years

Data source

Nationwide RKI interview and examination surveys 1997-1999 (GNHIES98) and 2008-2011 (DEGS1) based on a population registry sample and self-completed questionnaire, medical interview, automated medicine registration and examination.

Number of cases

• GNHIES98: n = 7,124

  • n = 333 people with known type 2 diabetes
  • n = 3,263 people without known diabetes

• DEGS1: n = 7,115 (of which n = 2,923 had also participated in GNHIES98)

  • n = 523 people with known type 2 diabetes
  • n = 4,043 people without known diabetes

• Data for the Hypertension indicator were collected completely among people aged 45-79 years.

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 east and west (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: In order to correct for deviations from the underlying reference population due to different participation rates or sampling probabilities, weighting factors were used when calculating the indicator. These adjust the surveys to the population structure of the reference population with regard to sex, age, federal state, German citizenship (yes / no), community type and education as of 31 December 1997 (GNHIES98) and 31 December 2010 (DEGS1). In DEGS1, the different participation probability of re-participants from GNHIES98 was also considered in the weighting.
• Absolute values: Number of persons with hypertension in the population aged 45-79 years with type 2 diabetes (reference population), determined by extrapolating the number in the sample to the number in the reference population.

• Age standardization: Age standardization and trend weighting was carried out by calculating the weighting factor in GNHIES98 using the age, sex and federal state structure of the reference population as of 31 December 2010.

Data quality

RKI interview and examination surveys provide representative results for the 18- to 79-year-old resident population of Germany. The population aged 80 years and over will only be included in future survey waves. As is the case in all population-based studies, underrepresentation of the seriously ill and those living in institutions must be assumed.