After implementation of the 2017 ACC/AHA guideline, the prevalence of HTN in the Khuzestan province dramatically increased by 27.04% and the level of awareness and control dropped by 23.17% & 31.78%, respectively. Accordingly, the overall prevalence of HTN was 42.85% and about 77.23% of hypertensive adult were not aware of their condition. Among those who were eligible for HTN therapy 14.22% received drug, which controlled the HTN in 28.94% of them. All hypertension-related risk factors remained significant after applying the new guideline; however, the strength of the association was reduced in the risk factors like WHR, BMI, alcohol consumption, water pipe usage and physical activity. Moreover, the association between HTN and history of DM, and CAD was reduced by 38%, and 62% respectively.
In order to reduce the major adverse of CVD events, ACC/AHA has recommended a lower threshold of SBP and DBS (130/80 mm Hg) for diagnosis of HTN compared to what had been suggested earlier (140/90 mm Hg); however, there is a debate about the proposed HTN cut-off and CVD benefit. Although some studies reported reducing the SBP to 120 mm Hg level significantly decreased the risk of CVD [11], a more substantial reduction rate was observed for 130–139 mm Hg versus < 120 mm Hg [12, 13]. Conversely, a recent systematic review and meta-analysis study found no CVD benefit from additional blood pressure lowering if the SBP at baseline was < 140 mm Hg [14] and the authors further declared implementation of this guideline caused a significant increase in the proportion of adult diagnosed with HTN, with no noticeable effect on the reducing CVD morbidly and mortality [15]. Here, we found the number of hypertensive patients was reached to 13,036 (42.85%) from 4,809 (15.81%) and this raise has been observed in all age group, ranging from 22.2% in 20–29 age group to 30.2% in 50–59 years old subjects. A lower increased rate has been reported in other countries; 22.4% in China (> 18 years) [16], 13.7% in the USA (> 20 years)[17], and 6–11% in Sweden (25–74 years) [15], which indicates the number of people with SBP 130–140 or DBP 80–90 was higher in Iran and this country would receive greater benefit about reducing the burden of CVD in the future by implementation of ACC/AHA guideline. Moreover, a noticeable shift of HTN prevalence has been observed among male population. Although about equal number of male and female were diagnosed with HTN previously (17.79% vs 14.70%), a more significant increased rate has been found in the male sex after applying the 2017 guideline (50.30% vs 38.70%). This transformation is more correlated with the higher rate of CVD mortality among male population in Iran, which indicates the necessity of further interventional strategies in this gender.
According to the JNC8 guideline, we found 45.94% of the hypertensive subjects were aware of HTN, which is lower than the previous awareness estimates in Iran (59.2%) [4]. After adopting the 2017 ACC/AHA, the awareness rate dropped to 22.77%, which was more noticeable in the 40–49 age group (21.65%). Since 45.36% of this age group are now classified under the HTN category, a substantial call to action for public awareness is warranted. Moreover, the HTN treatment strategy has been revised in 2017 ACC/AHA and those with SBP 130–139 or DBP of 80–89 were also recommended to received anti-hypertension treatment if they are + 65 years older, or the clinical CVD or 10-year atherosclerotic cardiovascular disease risk is 10% or greater [4]. Following this guideline, many high-risk adults might be protected against the development of HTN-related chronic diseases. However, the number of people who need anti-HTN treatment has been expected to increase from 8.1 million to 15.6 million in the USA and from 74.5 million to 129.8 million in China [6], which may impose a considerable impact on the health system in these countries. In this study, 4738 (15.53%) of total sample were eligible to receive HTN therapy based on JNC8. After ACC/AHA, additional 1724 subjects with SBP 130–139 or DBP of 80–89 and history of CVD or DM become candidate for pharmacological interventions, which increase the treatment demand to 21.18%. However, our study was limited to people aged 65 and younger; therefore, estimating the real impact of treatment in our population was not feasible. Another recent study conducted in Iran estimated that the number of adults met the criteria for treatment with anti- hypertensive medication increased from 13.4 million to 17.2 million [5]. Although the increased prevalence of HTN was more noticeable in Iran, the treatment burden in this country was lower compared to China & the USA, which might be due to smaller population of 65 + years old in Iran. Therefore, the impact of treatment costs on the health system under 2017 ACC/AHA guideline seems to be acceptable. However, the HTN control in Iran is relatively poor. Among those who were eligible for pharmacologic intervention, 19.40% take anti-HTN medication, which controlled the HTN in 60.72%. Under ACC/AHA guideline, the blood pressure < 130/80 mm Hg was considered as the target cut-off; therefore, the control rate was drop by 31.78% and reached to 28.94%, which highlight a great need to expand the public health infrastructure for further managing the substantial increase in the public health burden of HTN.
Considering the 2017 ACC/AHA guideline, 6574 participants younger than 65 years old have been additionally diagnosed with HTN, who might benefit from earlier interventions. Since these group of people are not eligible for pharmacological interventions, modification of life style and nutrients diet is critical to reduce the risk of HTN-related disorders in the future. Although the salt intake was not an independent risk factor for HTN, the mean of sodium intake was estimated to be 8.74 gr/day, which exceeds the current WHO recommendations (2 gr/day(d) of Sodium, equivalent to 5 gr/d of salt) [18]. Based on 2017 ACC/AHA, we estimated about 79.38% of hypertensive people consume salt over the threshold, 75%.82 need to lose extra weight, and 76.98% are required to do more physical activity.
We further evaluated the impact of 2017 ACC/AHA guideline on HTN-associated risk factors. All independent risk factors remained significant after implementation of the new guideline; however, the magnitude of the odds ratio reduced. Age was the strongest risk factor for HTN. Based on JNC8, the association between HTN and 60–65 aged group was 20.9-fold higher than HTN and 20–29 people; nevertheless, the association was reduced to 5.6-fold after adopting the updated version of the guideline. Similarity, we found a reduced rate of odds ratio in those with WHR ≥ 0.95 and obese people, alcohol consumption and waterpipe smoking in manifesting the HTN in the future, which might influence the further awareness strategies in the populations about the effect of lifestyle risk factors on HTN development. Although this is a cross sectional-based study and a causal relationship cannot be inferred, it seems the association between HTN and history of DM, and CVD was reduced by 38%, and 62%, respectively after applying the of 2017 ACC/AHA guideline, which might indicate the benefit of 2017 guideline.
This is a cross-sectional based study; and a causal relationship cannot be inferred. Moreover, based on the HTN 2017 ACC/AHA those with SBP 130–139 or DBP of 80–89 were also recommended to received anti-hypertension treatment if they are + 65 years older. However, our study was limited to people aged 65 and younger; and further study covering all range group is required to estimate the real impact of treatment after implementation of new guideline.