4363.0 - National Health Survey: Users' Guide, 2017-18  
ARCHIVED ISSUE Released at 11:30 AM (CANBERRA TIME) 30/04/2019   
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Blood pressure

Definition

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

Population

Information was obtained for persons aged 18 years and over, who agreed to have their measurements taken, in the 2017-18 NHS. Data was imputed (for further information see Imputation chapter) for those who did not have their measurements taken.

Methodology

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 Computer Assisted Interview (CAI) instrument would prompt for a third reading.

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


Blood pressure ranges
CategoryRange mmHg
NormalLess than 120/80
Normal - highFrom 120/80 to less than 140/90
HighFrom 140/90 to less than 160/110
Very highFrom 160/100 to less than 180/110
SevereFrom 180/110

Note: if either the systolic or diastolic reading was placed in a higher blood pressure level category, then the respondent was placed in that higher category.

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

Interpretation

Points to be considered in interpreting data for this topic include the following:
    • Non-response rates for physical measurements were higher in 2017-18 NHS than in the 2014-15 NHS. In 2017-18, 31.6% of respondents aged 18 years and over did not have their blood pressure measured. For these people, blood pressure was imputed. Blood pressure data presented in the 2017-18 NHS includes both measured and imputed data.

Comparability with 2014-15

Blood pressure data are considered directly comparable between the 2017-18 and 2014-15 NHS. A new imputation method was utilised in 2017-18, however this is believed to have minimal impact on results. For more information please see Appendix 2 Physical Measurements, National Health Survey: First Results, 2017-18 (cat. no. 4364.0.55.001).

More information regarding comparisons between 2014-15 NHS and previous cycles is available in the National Health Survey: Users' Guide, 2014-15 (cat. no. 4363.0).