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BLOOD PRESSURE

Definition

This topic refers to the diastolic and systolic measures of blood pressure, which were recorded by the interviewers during the interview.

Population

Information was obtained for all persons aged 5 years and over in the NHS and NNPAS who agreed to have their measurements taken.

Methodology

Information about blood pressure was collected in both the NHS and the NNPAS. Information on blood pressure was first published in the First Results publication based on the NHS only sample of approximately 18,900 people age 5 years and over. Updated results on blood pressure for the larger combined, core sample of approximately 30,300 people aged 5 years and over was published in the Updated Results publication. For comparison of blood pressure with NHS only items, the NHS file should be used and similarly for comparison with NNPAS only items, the NNPAS file should be used. However, for the most accurate information for blood pressure alone or comparison with other items collected in the core, the core file should be used. For more information on the structure of the AHS, see the Structure of the Australian Health Survey page of this Users' Guide.

Blood pressure measurements were taken towards the end of the survey and were voluntary. Respondents were invited to sit down and extend and relax their left arm, with their palm facing upwards. Interviewers were given a choice of three different sized cuffs to select from depending on respondent size. All measurements were taken on the left arm, unless there was a prohibitive reason such as an injury. Interviewers undertook two blood pressure readings using an automated blood pressure monitor in which systolic and diastolic pressures were displayed. If there was a significant difference (greater than 10 mmHg) between the readings, for either the diastolic or systolic readings, the CAI instrument would prompt for a third reading.

The follow blood pressure ranges were used to categorise blood pressure for persons aged 18 years and over.

The derived systolic and diastolic data items involve a combination of up to two readings. Unless there was only one reading, the first reading was generally not used. The majority of participating respondents had two readings taken, and in these cases the second reading was used for the measures of systolic and diastolic pressure. When a third reading was required to be taken, the second and third readings were averaged unless the third reading differed by 20 mmHg or more. If all readings had a variation of 20 mmHg or greater the derived measurement items were recorded as invalid readings.

Data items

The data items and related output categories for this topic are available in Excel spreadsheet format from the Downloads page of this product.

Interpretation

Points to be considered in interpreting data for this topic include the following:

• For 2011-12, 81.4% of respondents aged 5 years and over agreed to have their blood pressure measured, and 81.0% had a valid blood pressure reading obtained according to the systolic and diastolic calculation criteria used as described above. Therefore, blood pressure data presented as part of the AHS relates to the measured population only. Analysis of the characteristics of people who agreed to be measured compared to those who declined indicated that age and sex were factors in non-response. Females were more likely to decline, and non-response was most prevalent in children and then tended to increase with age.
• If the respondent agreed for the measurements to be taken, but then there was an equipment failure or an inability to get any reading for any readings, the agreement to be measured was retained in the ‘Whether blood pressure measured‘ item but the specific measurement where this occurred was recorded as a dump code. If the respondent refused to have a second or third reading taken then this was recorded as a refusal for that reading.