Hypertension is the most prevalent cardiovascular factors worldwide and is the main cause of death even in developed country [17]. Recently a large meta-analysis of 2939 sudden cardiac deaths (SCD) among 418,235 participants from 18 studies, showed that hypertension is associated with a twofold increase in risk of SCD and a 28% increase of SCD per 20 mmHg increment in SBP [18]. Moreover, in a pooled dataset from 44 low-income and middle-income countries including 1100507 participants, the authors showed that only 10.3% of hypertensive patients achieved BP control [9]. All these indicators demonstrate that hypertension is a public health problem in developed as well as developing countries. Tunisia, is a mild incomes country, and during the last decade, the Tunisian lifestyle, eating habits and the population ageing have widely changed; there has been an increase in cardiovascular risk factor [19]. Recently a national cross sectional Tunisian study “ATERA”, including 11 955 individuals showed that the prevalence of high blood pressure has increased to 50%, that of diabetes to 18% and that of obesity to 31% [20]. Face to these dramatic epidemiologic indicators, the Tunisian Society of Cardiology and Cardiovascular surgery, aimed to evaluate the cardiovascular profile of hypertensive patients and to assess the BP control, through a national flash study. In our knowledge, Nature HTN is the largest national survey of Hypertension in Africa. The most important findings of this registry is that the profile risk of the Tunisian has changed remarkably. In 2012, ben Romdhane et al published the results of TAHINA project, which was a Tunisian national survey including 8007 patients, aged between 35 and 70 years and examined across home visits. When comparing the results of TAHINA and Nature HTN among hypertensive patients, we found that the prevalence of illiterate people has decreased from 43–21.3%. Surprisingly, we found that the prevalence of diabetes among hypertensive people has deacreased from 62–39.4%, that of tobacco from 22–14% and that of obesity from 46–25% [11]. All these findings demonstrate that nowadays, the diagnosis of hypertension was made early before the development of diabetes and other comorbidities. That’s why the rate of diabetic among hypertensive patients has decreased. This finding goes along with the improvement of the educational level between the two studies, certainly the Tunisian citizen ‘s awareness of blood pressure risks, and management methods has evidently increased.
The second important finding of our registry is the improvement of BP control; in 2005, Ben Romdhane et al had conducted a Tunisian cross-sectional survey on 1837 adults, aged between 40–69 years old, only 13.2% of hypertensive individuals were controlled [7]. Then, hypertension control increased to 24.1% in the TAHINA project (2012) and recently we demonstrated in NATURE HTN that BP was controlled in 51.9% of our population when we consider 140/90 as a target. This rate is close to the rate achieved in many developed countries. Control of hypertension remains elusive nationally, despite widespread availability of effective therapies.
In fact, control hypertension remains a health problem in not only low and middle incomes countries but also even in high incomes countries. Ikeda et al, in a comparative analysis of national surveys in 20 countries, showed that hypertension was treated in 13.8–80.5% of hypertensive patients in the different countries but was controlled only in 4.4 % to 59.1% [10]. Recently, Pan et al reported a control of 60% of hypertensive patients in Taiwan, but the prevalence of diabetes, obesity and smoking in this cohort were lower compared to our population [21].
In California, the implementation of a large-scale hypertension program has been associated with a significant increase in hypertension control compared to the others cities of US. The control rate increased from 55% in 2001 to 64% in 2009. Key elements of this program included a comprehensive hypertension registry, development and sharing of performance metrics, evidence-based guidelines, medical assistant visits for blood pressure measurement, and single-pill combination pharmacotherapy [22].
Recently the FLASH 2019 study, a national French study has showed a rate of 54% of BP control [23]. This rate was stable in between the different Flash studies (2009–2019), a therapeutic inertia was advanced to explain the lack of BP control improvement. The monotherapy kept downgrading in the different guidelines but Girerd et al reported that the rate of monotherapy has increased according to the different FLASH studies, changing from 44% in 2009 to 55% in 2019, and he related the cause to the difficulties of drug reimbursement during the last years.
In our population, the BP control has improved, the reimbursement of Stage II and III hypertension costs as well as the availability of generic molecules, the improvement of the education level of the Tunisian population has certainly contributed to this achievement. However, management of patients in public sector was found as an independent predictor of uncontrolled hypertension. Certainly, this could be explained in part by the discrepancy of drug availability between the two sectors, the quality of health insurance and the lack of one single pill in public sector. However, we it is worth considering that we found in our cohort that patients treated in public sector seem to be at higher cardiovascular risk with higher prevalence obesity, diabetes, smoking with a less frequently physical activity. All these factors were identified as predictors of uncontrolled hypertension in our population and were behind the bad control of BP in public sector. Moreover, patients treated in the private sector ,underwent more frequently out office measurement, they had lower heart rate, better follow up with more frequent lab test. We noted also that ARB Class was more frequently prescribed in private sector and this class is associated with better tolerance and persistence. In public sector, the majority of patients take their drugs from the hospital. ARB class was not available in public sector. All these findings should be considered by the health ministry to improve the conditions of management of hypertensive patients in public sector where patients with the highest cardiovascular profile were treated.
The reimbursement of stage I hypertension costs by the national security fund is another point to discuss and which is missing both, in private and public sector. There is an urgent need for a comprehensive integrated population-based intervention program to improve the growing problem of hypertension in Tunisia.
Heart rate was another strong predictor of uncontrolled BP in our population and this is could be related to the big prevalence of overweight and obesity as well as the low physical activity practice. One patient out of five has a heart rate > 80bpm in our model. Recently, the ESC/ESH guidelines classified this clinical finding among the factors influencing cardiovascular risk [14, 24]. The Nice guidelines recommended to downgrade beta-blockers use and to limit their use to the specific settings [25], but we thought that sympathic activation is well involved in the physiopathology of hypertension in Tunisian people, as it was demonstrated by the high Heart rate in our population [26]. Therapeutic education should be highly considered and practicing sports to reduce BP level highly recommended. In developed countries, 60% of the population practice sport regularly [27], in our study only 14% performed a physical activity. Recently, Sata rosa et al showed that active life style improves heart rate variability as well as reduces oxidative stress in hypertensive people and it improves BP control [28]. On the other hand, Beta blockers should not be dismissed, and patients with high HR, definitely need this therapeutic class.
Patients with a history of coronary disease were more in target in our model and ischemic cardiomyoapthy was even identified as a predictor of controlled blood pressure. Many previous studies have confirmed these findings [6, 7, 10, 29], in fact patients with coronary disease are more compliant to their drugs and generally receive at least two class (beta blockers and ACE or ARB), moreover they consult their doctors more frequently.