Study assesses the prevalence of resistant hypertension in Brazil

Preliminary data indicate that the problem affected 16% of the 1,692 hypertensive individuals assessed. A second phase of the study will investigate which treatment is more effective in an effort to standardize care under the Unified Health System.

By Karina Toledo

Agência FAPESP – Determining the prevalence of resistant hypertension among Brazilians and standardizing the treatment of these patients under the Unified Health System (SUS) were the goals of a study that was conducted at 25 university hospitals throughout Brazil under the coordination of researchers at the Heart Institute (InCor) of the University of São Paulo School of Medicine (FMUSP).

A preliminary analysis detected the problem in 16% of the 1,692 hypertensive individuals assessed. The data were presented by Eduardo Moacyr Krieger, a principal investigator and Vice President of FAPESP, during the World Health Summit Regional Meeting – Latin America, an international event organized by the FMUSP, on April 6-8, 2014.

“A resistant hypertensive individual is one whose blood pressure remains elevated even after treatment with adequate doses of three different classes of anti-hypertensive drugs, with one of them necessarily being a diuretic,” Krieger explained.

In these cases, specialists estimate that the risk of developing serious diseases such as stroke, heart attack, heart failure or kidney disease is three times higher than in patients whose hypertension is under control. Those with controlled hypertension already have a higher risk of such diseases than the normotensive population.

Resistant hypertension is considered to be a growing global public health problem, especially in light of increasing life expectancy and the growing epidemics of sleep apnea, diabetes and obesity. Added to this situation is the hypothesis that excessive dietary consumption of salt could be contributing to the growth in the number of cases.

“There is a consensus regarding the need to treat hypertension with three different classes of medicines before it can be considered resistant. But when the treatment fails, the question always remains: what should the fourth or fifth drug added to the triple regimen be? There is very little information in the scientific literature, so we decided to propose this project and specifically direct it toward the Brazilian population,” Krieger said.

Given the name “Resistant Hypertension Optimal Treatment” (ReHOT), the multicenter study has support from the Ministry of Health, the National Council for Scientific and Technological Development (CNPq) and FAPESP through its Research in Public Policies for the National Healthcare System: Shared Health Management (PPSUS) program.

In all, the study included 1,927 patients with severe hypertension – a systolic blood pressure (maximum) above 160 millimeters of mercury (mmHg) and a diastolic blood pressure (minimum) of 110 mmHg – in a representative sample of the Brazilian population. The ideal blood pressure value is currently approximately 120/80 mmHg, with hypertension considered 140/90 mmHg.

Blood pressure was measured in a doctor’s office, as well as through a method known as ambulatory blood pressure monitoring (ABPM). In this technique, measurements are taken every 20 minutes over a 24-hour period using a monitor attached to a belt worn around the body, with the goal of recording the variations that occur during the sleep-wake cycle.

The eligible patients were treated over a three-month period with suitable doses of medicines available through the public health network. After this period, a second evaluation revealed that 84% then had normal blood pressure.

Those patients who, after three months of treatment, presented a clinical blood pressure above 140/90 mmHg and a 24-hour ambulatory pressure of 130/80 mmHg were considered resistant. In the second stage of the study, these patients will be randomly divided into two groups. Half will be treated with the drug clonidine, and the other half will be treated with the drug spironolactone.

“Whichever of the two drugs proves to be most effective may be included in the standardized SUS treatment and administered together with the other three classes of anti-hypertensives already in use,” Krieger explained.

For Krieger, the ReHOT project exemplifies the importance of the relationship between universities and public authorities in conducting research to improve the prevention and treatment of diseases in the public health network. “The university’s obligation does not stop at training the physician. The university has the knowledge and the research centers that are best suited to conducting cost-benefit analyses. Potential sponsorship for this also preferably comes from public authorities,” he said.

The scope of the ReHOT project was published in a 2013 article that appeared in the journal Clinical Cardiology. Krieger presented the preliminary findings during the symposium “Deciphering the Public Health Situation in Brazil,” which was part of the program of the World Health Summit Regional Meeting – Latin America.

Deciphering public health

During the same session, FMUSP researcher Paulo Andrade Lotufo presented preliminary findings from the Brazilian Longitudinal Study of Adult Health (ELSA Brasil), whose objective is to study the incidence of chronic diseases, particularly cardiovascular diseases and diabetes, along with their risk factors. The sample is composed of 15,105 employees between the ages of 35 and 74 at six public universities.

Moyses Szklo, a professor at the Johns Hopkins Bloomberg School of Public Health, presented data from the ERICA Project – Study on Cardiovascular Risks in Adolescents, which includes a sample of 75,000 adolescents ranging in age from 12 to 17 and involves collaboration with researchers from 35 Brazilian institutions.

Another study that is underway, presented by Flávio Danni Fuchs, a professor at the Federal University of Rio Grande do Sul (UFRGS), is entitled “Prevention of Cardiovascular Events in Patients with Pre-Hypertension and Arterial Hypertension” (Prever). In this case, the objective is to investigate whether medical treatment of individuals with pre-hypertension reduces the incidence of arterial hypertension and to determine which combination of drugs should be used.

Joyce Schramm, a researcher at the Sergio Arouca National School of Public Health (ENSP-Fiocruz), presented data from her studies on the disease burden in Brazil. The results indicate a decrease in the number of cases of death and incapacity caused by infectious diseases and an increase in the number of cases arising from non-infectious diseases such as cardiovascular disease and mental disorders.

World Health Summit

Focused on the main challenges that Latin America faces in the area of health, the World Health Summit Regional Meeting – Latin America included lectures from the medical schools that are part of the M8 Alliance. This network is composed of 16 institutions, including the FMUSP, in 14 countries.

The meeting was designed to engage the scientific community, politicians and representatives of both non-governmental organizations and the private sector in a discussion about solutions to global health challenges based on scientific knowledge. These challenges include the prevention and control of diseases, the development of innovative approaches and the use of more effective practices.

The program was organized into five tracks: “Healthy Life Expectancy,” “Urban Health/Health in Megacities,” “Increased Research Capacity to Incorporate Technologies,” “Management of Health Systems to Ensure Universal Coverage,” and “Health Education.”

On April 7, FAPESP President Celso Lafer participated in the meeting by chairing the panel session organized by Gary Gibbons, Director of the National Heart, Lung and Blood Institute (NHLBI), a division of the National Institutes of Health (NIH) of the United States.

FAPESP Scientific Director Carlos Henrique de Brito Cruz was the moderator, along with José Eduardo Krieger (InCor-USP), USP Dean of Research, at the symposium “Challenge to Improve Prevention and Outcomes in Cardiovascular Diseases.” In addition to Gibbons, the session included Joaquim Bernoya (Director of Research at the Cardiovascular Unit of Guatemala), Jose Patricio Lopez-Jaramillo (University of Santander, Colombia) and Alexandre da Costa Pereira (InCor-USP).