The prevalence of hypertension is high among the Yazd adult population with inappropriate awareness and controlled hypertension rates. Less than half of aware patients, who were treated, had controlled blood pressure.
The results indicate that Yazd is among the areas with high blood pressure prevalence compared to similar studies in Iran and the world. The prevalence of hypertension in the world has also been reported 28.8% in high and 31.5% in low-income countries, indicating a worsening situation in Yazd. This might be justified by the different prevalence of risk factors due to ethnicity and lifestyle changes, or different age groups in the study. Having screening intervention programs in place, may increase the difference in prevalence of diagnosed and treated patients across regions, as well as in one area over different years.Almost 50% of Yazdi adults are aware of their hypertension, which is lower than in high-income countries (67%) but higher than low/middle-income countries (37.9%).  In different countries this awareness has been reported from 25 to 75%.  Awareness in Yazd is lower compared to most studies in Iran (69.2% in Isfahan,  60.5% in Tabriz,  and 57% in Kerman . It is slightly higher than Golestan's (46.2%) and a previous study in Yazd (43.7%). [12,16] Over the past decade, the 5% awareness increase in Yazd was not satisfactory, considering increased access to health centers and increase in the number of health insured.The study shows that about three-quarters of patients (71.5%), who were aware of their disease, had visited by the physician during the past three months. Although the treated hypertension in Yazd is higher than the world average (36.9%),  it is more inadequate than other studies in Iran. [9,12] The availability and affordability (low cost) of health care services have made this index more favorable in Iran than in the world - even in high-income countries (55.6%). [16,27] Un-prescribed drug use and differences in the definition of treated people may be other reasons for this difference. Despite treatment, only 39% of the participants had controlled hypertension, which is close to the worldwide statistics (37.1%), although it less than high-income countries (50.4%).  Although the difference between treated and controlled hypertension was reported in all studies, in Iran, Isfahan (59.1%) and Tabriz (68.5%) reported a better-controlled situation [9,12] suggesting poor control of hypertension in Yazd. In Yazd, 71.5% of those who were aware of their hypertension were visited by physician for receiving medication. However, in both treated and untreated groups, blood pressure control did not differ (38.9% vs. 38.7%). This was lower than the result of several studies including some from developed countries,  and was similar to another multinational study (32.5%). Controlled hypertension was higher among females, younger age groups; health insured and educated participants which were in line with other studies.[12,31] More physicians' visit (by women), lack of other underlying diseases in young population, and low cost access to health care for the insured, explain these predictors for better control of hypertension according to the regression analysis. A comparison of blood pressure control status in Yazd in this study with the previous study shows threefold growth. Since awareness and treatment of the disease have not changed, improved quality of treatment by physicians has been effective. The high awareness and uncontrolled hypertension may justify irregular follow-up by family physicians and primary health centers, especially in the urban areas.
Misuse of medication or lack of regular patient care, as well as inadequate medication administration, can be a cause of the disease poor control.
After adjustment, patients with older age, history of diabetes, female sex, and health insured were more likely to aware of their hypertension. More elderly referrals to physicians and health centers for treatment and periodic care justify older people's awareness of their blood pressure compared to younger adults. In this study, less awareness of men than women can be due to lower access to health centers, employment and less attention to their health. This association between age and sex has been confirmed in other studies. [9,12,16] However, the odds ratios between sex-age groups in geographic regions vary depending on the level of education, availability, and cost of health services.
In this study, adult education did not correlate with their awareness, which is consistent with the findings of Katibeh et al. findings in Yazd.  However, most studies have reported a relationship between their education and awareness of hypertension. [33,34] Also, there was no relationship between high education and treated hypertension, as well as the control of hypertension. Higher education in people has no effect on the management of the disease, unlike the results of others, so it requires further investigation. Individuals' health literacy appears to be more important than education for health care.
Although health insurance was not associated with patients being treated, insurance was a predictor of hypertension awareness and control. The positive effect of health insurance was also reported in other studies.  This can be due to the reduced cost of receiving services in continuing care.
In our study, having a history of diabetes is a predictor for awareness and treatment of hypertension. Others have confirmed that having another medical condition (diabetes, hyperlipidemia, etc.) is associated with the awareness and treatment of hypertension. [9,34,36] It will cause people to go to health centers; as a result, hypertension will be diagnosed sooner, and medication will be started. However, having diabetes was not a predictor for blood pressure control. Different goals in defining blood pressure control and various guidelines in diabetic patients have made blood pressure control more difficult in this group. 
Strengths and limitations
The strengths of this study are the large sample size with random multi-stage cluster sampling from different urban and rural areas, 95% participation rate, and, most importantly the three measurements of blood pressure at home according to the standard protocol by trained health care providers. Investigating the relationship between tobacco smoking, obesity, physical activity, and diabetes history with hypertension awareness and control are among the other advantages of this study. This study, however, had some limitations. This cross-sectional study and cannot investigate the causality. Hypertensive risk factors such as stress, dietary habits, and alcohol use have not been analyzed. Tobacco smoking, physical activity, and diabetes were self-reported which may produce bias. The details of the drug adherence are an important variable for control of hypertension, which was not recorded in this study. Also, it was not considered the relationship between economic factors and health services utilization with awareness and control of hypertension.