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1.07 High blood pressure

Why is it important?

High blood pressure, also referred to as hypertension, is a major risk factor for stroke, coronary heart disease, heart failure, kidney disease, deteriorating vision and peripheral vascular disease leading to leg ulcers and gangrene. The National Heart Foundation of Australia defines high blood pressure as a systolic blood pressure greater than 140 mmHg and/or diastolic pressure greater than 90 mmHg and/or patient receiving medication for high blood pressure (NHF 2010). Major risk factors for high blood pressure include increasing age, poor diet (particularly high salt intake), obesity, excessive alcohol consumption, and insufficient physical activity (AIHW 2011c; WHO 2013). A number of these risk factors are more prevalent among Indigenous Australians (see measures in Health Behaviours).

A study of Indigenous Australians living in urban WA found that, after controlling for other cardiovascular risk factors, those with high blood pressure were twice as likely to die or be hospitalised due to a cardiovascular event (Bradshaw et al. 2009). It is estimated that high blood pressure is responsible for 6% of the health gap between Aboriginal and Torres Strait Islander peoples and non-Indigenous Australians (Vos et al. 2009; Vos et al. 2007).

While for some people, the propensity to develop high blood pressure appears to be inherited, it can often be prevented or controlled by leading an active and healthy life, remaining fit, avoiding obesity and diabetes and, if necessary, taking regular medication (Semlitsch et al. 2013; Bunker 2014; NHF 2010). For those with high blood pressure, treatment with long-term medication can reduce the risk of developing complications, although, not necessarily to the levels of unaffected people (AIHW 2011c). Reducing the prevalence of high blood pressure is one of the most important means of reducing serious circulatory diseases, which are the leading cause of death among Indigenous Australians (see measure 1.23).

Findings

Based on both measured and self-reported data from the 2012–13 Health Survey, 27% of Indigenous adults had high blood pressure. Rates increased with age and were higher in remote areas (34%) than non-remote areas (25%). Twenty per cent of Indigenous adults had current measured high blood pressure. Of these adults, 21% also reported diagnosed high blood pressure. Most Indigenous Australians with measured high blood pressure (79%) did not know they had the condition; this proportion was similar among non-Indigenous Australians. Therefore, there are a number of Indigenous adults with undiagnosed high blood pressure who are unlikely to be receiving appropriate medical advice and treatment. The proportion of Indigenous adults with measured high blood pressure who did not report a diagnosed condition decreased with age and was higher in non-remote areas (85%) compared with remote areas (65%). In 2012–13, 10% of Indigenous adults reported they had a diagnosed high blood pressure condition. Of these, 18% did not have measured high blood pressure and therefore are likely to be managing their condition. Indigenous males were more likely to have high measured blood pressure (23%) than females (18%). The survey showed that an additional 36% of Indigenous adults had pre-hypertension (blood pressure between 120/80 and 140/90 mmHg). This condition is a signal of possibly developing hypertension requiring early intervention. In 2012–13, after adjusting for differences in the age structure of the two populations, Indigenous adults were 1.2 times as likely to have high measured blood pressure as non-Indigenous adults. For Indigenous Australians, rates started rising at younger ages and the largest gap was in the 35–44 year age group. Analysis of the 2012–13 Health Survey found a number of associations between socio-economic status and measured and/or self-reported high blood pressure. Indigenous Australians living in the most relatively disadvantaged areas were 1.3 times as likely to have high blood pressure (28%) as those living in the most relatively advantaged areas (22%). Indigenous Australians reporting having completed schooling to Year 9 or below were 2.1 times as likely to have high blood pressure (38%) as those who completed Year 12 (18%). Additionally, those with obesity were 2 times as likely to have high blood pressure (37% vs 18%). Those reporting fair/poor health were 1.8 times as likely as those reporting excellent/very good/good health to be have high blood pressure (41% vs 22%). Those reporting having diabetes were 2.2 times as likely to have high blood pressure (51% vs 23%), as were those reporting having kidney disease (57% vs 26%). One study in selected remote communities found high blood pressure rates 3–8 times the general population (Hoy et al. 2007). Most diagnosed cases of high blood pressure are managed by GPs or medical specialists. When hospitalisation occurs it is usually due to cardiovascular complications resulting from uncontrolled chronic blood pressure elevation. During the two years to June 2013, hospitalisation rates for hypertensive disease were 2.4 times as high for Aboriginal and Torres Strait Islander peoples as for non-Indigenous Australians. Among Aboriginal and Torres Strait Islander peoples, hospitalisation rates started rising at younger ages with the greatest difference in the 55–64 year age group. This suggests that high blood pressure is more severe, occurs earlier, and is not controlled as well for Indigenous Australians. As a consequence, severe disease requiring acute care in hospital is more common. GP survey data collected from April 2008 to March 2013 suggest that high blood pressure represented 4% of all problems managed by GPs among Indigenous Australians. After adjusting for differences in the age structure of the two populations, rates for the management of high blood pressure among Indigenous Australians were similar to those for other Australians. In December 2013, Australian Government-funded Indigenous primary health care organisations provided national Key Performance Indicators data on around 28,000 regular clients with Type 2 diabetes. In the six months to December 2013, 64% of these clients had their blood pressure assessed and 44% had results in the recommended range (AIHW 2014w).

Implications

The prevalence of measured high blood pressure among Indigenous adults was estimated as 1.2 times as high as for non-Indigenous adults and hospitalisation rates were 2.4 times as high, but high blood pressure accounted for a similar proportion of GP consultations for each population. This suggests that Indigenous Australians are less likely to have their high blood pressure diagnosed and less likely to have it well controlled given the similar rate of GP visits and higher rate of hospitalisation due to cardiovascular complications.

Research into the effectiveness of quality improvement programmes in Aboriginal and Torres Strait Islander primary health care services has demonstrated that blood pressure control can be improved by a well-coordinated and systematic approach to chronic disease management (McDermott et al. 2004). Identification and management of hypertension requires access to primary health care with appropriate systems for the identification of Aboriginal and Torres Strait Islander clients and systemic approaches to health assessments and chronic illness management.

The Indigenous Australians' Health Programme, which commenced 1 July 2014, provides for better chronic disease prevention and management through expanded access to and coordination of comprehensive primary health care. Initiatives provided through this programme include nationwide tobacco reduction and healthy lifestyle promotion activities, a care coordination and outreach workforce based in Medicare Locals and Aboriginal Community Controlled Health Organisations and GP, specialist and allied health outreach services serving urban, rural and remote communities, all of which can be used to diagnose and assist Indigenous Australians with high blood pressure. Additionally, the Australian Government provides GP health assessments for Indigenous Australians under the MBS, of which blood pressure measurement is one key element, with follow-on care and incentive payments for improved management, and cheaper medicines through the PBS.

The Australian Government-funded ESSENCE project 'essential service standards' articulates what elements of care are necessary to reduce disparity for Indigenous Australians for high blood pressure. This includes recommendations focusing on primary prevention through risk assessment, awareness and early identification and secondary prevention through medication.

Figure 1.07-1 Aboriginal and Torres Strait Islander people with measured/self-reported high blood pressure by age and remoteness, 2012–13
Aboriginal and Torres Strait Islander people with high blood pressure

Figure 1.07-1 shows measured/self reported data on high blood pressure from the 2012–13 Health Survey. Rates increased with age and were higher in remote areas (34%) than non remote areas (25%).

Source: ABS and AIHW analysis of 2012–13 AATSIHS

Figure 1.07-2 Percentage of Aboriginal and Torres Strait Islander people 18 years and over with normal, pre-hypertensive, and high measured blood pressure, by those who did and did not self-report having high blood pressure, 2012–13
normal, pre-hypertensive, and high measured blood pressure

Figure 1.07-1 shows twenty per cent of Indigenous adults had current measured high blood pressure. The survey showed that an additional 36% of Indigenous adults had pre-hypertension (blood pressure between 120/80 and 140/90 mmHg). This condition is a signal of possibly developing hypertension requiring early intervention.

Source: ABS and AIHW analysis of 2012–13 AATSIHS

Figure 1.07-3 Measured high blood pressure, by Indigenous status, age and sex, 2011–13
chart showing Measured high blood pressure

Figure 1.07-3 shows for Indigenous Australians, rates of measured high blood pressure start rising at younger ages and the largest gap is in the 35–44 year age group.

Note: Total is age-standardised

Source: ABS and AIHW analysis of 2012–13 AATSIHS