CARDIOVASCULAR JOURNAL OF AFRICA • Volume 33, No 4, July/August 2022 AFRICA 211 doubled since the 1998 survey, with 55% of men and 63% of women aged 45–54 years, and 74 and 78% of men and women aged 55–64 years living with hypertension. WHO-SAGE wave 1 (2007–2010) data published in 2013 reported that the odds of having hypertension were significantly higher in 40- to 59-year-olds (OR: 2.98, 95% CI: 0.569–15.58; n = 1 134) and in 60- to 79-year-olds (OR: 38.89, 95% CI: 5.549–272.6; n = 360) compared to < 40-year-old adults (n = 569; p < 0.001).150 An analysis of the same dataset but including only those South African adults over 50 years (n = 3 840) showed that around threequarters of adults had hypertension (overall prevalence 77.3%, men 74.4%, women 79.6%) with the highest prevalence observed in women aged 60 to 69 years (81.6%).43 In this nationally representative sample, 38.1% of the adults with hypertension were aware of their hypertension, 32.7% were being treated and 17.1% had their hypertension under control, with four out of five hypertensive older adults showing uncontrolled blood pressure. Hypertension in the over 50-year-old group did not differ significantly between urban and rural populations in South Africa and was higher than any previous figures for African adults27 and higher than all other WHO-SAGE countries (China, India, Ghana, Mexico, Russia),61 with the lowest levels of hypertension diagnosis across all six countries.64. In 2016, Irazola et al. reported the prevalence of hypertension from four urban South African communities at 61% in 45- to 54-year-olds and 70% in 55- to 64-year-olds.154 A further 23 and 18% of 45- to 54-year-olds and 55- to 64-year-olds, respectively, were diagnosed with pre-hypertension (SBP between 120 and 139 mmHg and/or DBP between 80 and 89 mmHg in the absence of a diagnosis of hypertension or treatment).154 Data from the CRIBSA study published in 2015 reported a similar prevalence of hypertension, with the highest levels observed in women in both age groups (45- to 54-year-olds: 60.6% in women vs 58.2% in men; and 55- to 64-year-olds: 77.1% in women vs 63.6% in men).157 In another regional study in Cape Town comparing two independent cross-sectional surveys in 2008–2009 and 2014–2016, results showed that in 2008–2009 screen-detected hypertension was highest in ≥ 70-year-olds, while in 2014–2016 the peak was in 40- to 49-year-olds.152 The recorded prevalence of hypertension from the study cohort in 2008–2009 was 33% in 40- to 49-yearolds, 50% in 50- to 59-year-olds and 68% in 60- to 69-year-olds. In 2014–2016, this had increased significantly in all groups to 58% in 40- to 49-year-olds, 71% in 50- to 59-year-olds and 83% in 60- to 69-year-olds. Relying on self-reported hypertension status only, a 2015 survey conducted with 28 007 Gauteng adults reported a hypertension prevalence of 21% in 48-to 57-year-olds, and 32% in 58- to 67-year-olds.155 In 2013, a screening campaign in five of the nine South African provinces reported a hypertension prevalence in selfselected urban and peri-urban adults of 57.3 and 54.1% in 45- to 54-year-old men and women, respectively, and 74.8 and 68.3% in 55- to 64-year-old men and women, respectively.28 Another screening campaign conducted in Zandspruit (outside of Johannesburg), Gauteng, in 2012–2014 reported a prevalence of elevated blood pressure (≥ 140/90 mmHg) as 55% in 45 to 54 year olds (n = 889), and 63% in 55 to 64 year olds (n = 109).158 Treatment use in studies recruiting volunteers as part of a screening campaign report higher prevalences of hypertension than most studies (53.0 and 57.4% in 45- to 54-year-old men and women, respectively; 60.8 and 70.2% in 55- to 64-year-old men and women, respectively), as well as the percentages of those who were controlled on treatment (42.1 and 44.5% in 45- to 54-year-old men and women, respectively; 41.8 and 47.2% in 55- to 64-year-old men and women, respectively).28 These findings may suggest that such screening programmes disproportionately attract individuals who know their diagnosis and are actively seeking to monitor their treatment response. When examining data for the different ethnic groups collected as part of the screening campaign described above, in comparison to self-identified black women, Indian women were more likely (OR: 1.31, 95% CI: 1.01–1.69) and self-identified white women were less likely (OR: 0.55, 95% CI: 0.44–0.69) to have hypertension. Other factors associated with having hypertension in both men and women were increasing age, being resident in the Eastern Cape or the Free State (compared with the Western Cape), and having multimorbidity (especially having a cardiac problem, stroke, diabetes or being overweight or obese).28 Data from two studies conducted at the Dikgale HDSS site in Limpopo and the Agincourt HDSS site in Mpumalanga have reported quite disparate hypertension prevalences. In Dikgale, a hypertension prevalence of 41% in 40 to 49 year olds, 48% in 50 to 59 year olds and 51% in over 60 year olds were reported.156 While the prevalence of hypertension was similar between men and women in the 55- to 64-year-old group (47 and 46%, respectively), in the younger 45- to 54-year age group more women than men were hypertensive (43 vs 35%).26 Data collected during household visits in Agincourt, Mpumalanga, in 2014–2015 (the HAALSI study) showed hypertension prevalence rates of 45% in 40 to 49 year olds, 64% in 50 to 59 year olds, and 74% in 60 to 69 year olds.151 Interestingly, rates of hypertension awareness were much higher than anywhere reported previously (80% at age 40–49 years, 86% at age 50–59 years, and 94% at age 60–69 years), possibly as a result of continued research and surveillance efforts in the region. However, while many had received antihypertensive treatment (47% at age 40–49 years, 64% at age 50–59 years and 75% at age 60–69 years), fewer adults were continuing to stay on and take their blood pressure medication, particularly in the younger groups (31% at age 40–49 years, 45% at age 50–59 years and 58% at age 60–69 years). In an attempt to prevent hypertension and reduce population blood pressure, in June 2016 South Africa implemented legislation101 mandating maximum sodium levels in a range of manufactured foods that contribute significantly to salt intake in a population, which was updated with a second level of sodium lowering in 2019.108,109 The diet section in this report discusses the evidence on salt intake in South Africa and, as yet, there are few data to assess the impact of this legislation on population sodium intakes or on blood pressure. Given the evidence and according to our grading criteria, grades A and B are attributed to the prevalence, and policy and implementation grading criteria for hypertension, respectively (Table 3). Adopting standardised methods of measuring blood pressure is recommended across studies, and as the more immediate changes in blood pressure anticipated as a result of the sodium legislation are expected to be relatively small,160 this attention to measurement technique is critical to not miss these changes in blood pressure. However, the evidence reviewed suggests that, currently, South Africa is not on track to realise either the South African national or global target.
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