Access to and use of high blood pressure medications in Brazil

ABSTRACT OBJECTIVE To analyze the access to and use of medicines for high blood pressure among the Brazilian population according to social and demographic conditions. METHODS Analysis of data from Pesquisa Nacional Sobre Acesso, Utilização e Promoção do Uso Racional de Medicamentos (PNAUM – National Survey on Access, Use and Promotion of Rational Use of Medicines), a nationwide cross-sectional, population-based study, with probability sampling, carried out between September 2013 and February 2014 in urban households in the five Brazilian regions. The study evaluated the access and use of medicines to treat people with high blood pressure. The independent variables were gender, age, socioeconomic status and Brazilian region. The study also described the most commonly used drugs and the percentage of people treated with one, two, three or more drugs. Point estimations and confidence intervals were calculated considering the sample weights and sample complex plan. RESULTS Prevalence of high blood pressure was 23.7% (95%CI 22.8–24.6). Regarding people with this condition, 93.8% (95%CI 92.8–94.8) had indication for drug therapy and, of those, 94.6% (95%CI 93.5–95.5) were using the medication at the time of interview. Full access to medicines was 97.9% (95%CI 97.3–98.4); partial access, 1.9% (95%CI 1.4–2.4); and no access, 0.2% (95%CI 0.1–0.4). The medication used to treat high blood pressure, 56.0% (95%CI 52.6–59.2) were obtained from SUS (Brazilian Unified Health System), 16.0% (95%CI 14.3–17.9) from Popular Pharmacy Program, 25.7% (95%CI 23.4–28.2) were paid for by the patients themselves and 2.3% (95%CI 1.8–2.9) were obtained from other locations. The five most commonly used drugs were, in descending order, hydrochlorothiazide, losartan, captopril, enalapril and atenolol. Of the total number of patients on treatment, 36.1% (95%CI 34.1–37.1) were using two medicines and 13.5% (95%CI 12.3–14.9) used three or more. CONCLUSIONS Access to medicines for the treatment of high blood pressure may be considered high and many of them are available free of charge. The most commonly used drugs are among those recommended as first-line treatment for high blood pressure control. The percentage of people using more than one drug seems to follow the behavior observed in other countries.


INTRODUCTION
Non-communicable diseases (NCD) are a global health problem and have influenced worldwide initiatives aimed to their control and reduction 1 . In Brazil, NCD represent a high percentage of diseases, accounting for much of the mortality and the higher cost of hospitalizations, especially among older adults 21 . Schmidt et al. 31 report that despite the increase in crude mortality rates in recent years, age-specific mortality rates have decreased. According to the author, this was due to the success of a number of public policies to reduce tobacco use and expand access to basic health care. Prominent among these public policies are Plano de Reorganização da Atenção ao Diabetes e Hipertensão a (Plan for the Reorganization of Care for Arterial Hypertension and Diabetes Mellitus, Política Nacional de Medicamentos 18  Among NCD, high blood pressure accounts for most of the patients 31 . High blood pressure is a treatable medical condition and, if properly controlled, can delay or even prevent the development of symptomatic cardiovascular disease 23 . Medications play an important therapeutic role in hypertension care, both for their low cost in the early stages of the disease and for adherence to treatment, which, up to now, has been higher than adherence to lifestyle changes 12 . The global scenario of NCD led the World Health Organization to launch, in 2012, the challenge to reduce mortality from these diseases by 25.0% by 2052 2 . The WHO considered access to medicines an essential component in achieving this goal 2,6 .
In Brazil, basic health care policies, including the expansion of free access to drugs, are considered examples of public initiatives 3 and control of NCD. The objective of this study was to analyze the access to and use of medicines for high blood pressure among the Brazilian population, according to social and demographic conditions.

METHODS
The data for this analysis is taken from PNAUM (National Survey on Access, Use and Promotion of Rational Use of Medicines), a cross-sectional, population-based study. The study population of PNAUM consisted of people living in permanent private households in urban areas of the five Brazilian regions. The study analyzed data of people aged 20 or older. The questionnaires were answered directly by the person or by a caregiver, when they were unable to communicate or provide information on diseases and medicines used.
The sampling plan was complex and resulted in a probability sampling of the Brazilian population residing in urban areas of Brazil. Information on the sample, sampling procedures and other methodological procedures of PNAUM, including instruments used in the interview, field operation aspects and specificities of data collection are available in the PNAUM methodological article 17 .
The use of medicines to treat high blood pressure was investigated based on the following questions: "Has a doctor ever said you have hypertension or high blood pressure?"; "Do you have any medical indication to take any kind of medicine for high blood pressure?"; "Are you taking any of those medicines?". Later, they were asked about the drugs being used for high blood pressure and detailed information on source and payment, among others aspects. Whenever possible, the drug names were copied from the packaging. When no packaging was available, the names declared by the interviewees were recorded. Companies) d (A/B, C, D/E) and Brazilian region (North, Northeast, Southeast, South, Midwest). The denominator in calculating prevalence of use was the total number of people aged 20 or over in the sample, with 95% confidence intervals (95%CI).
The access to medicines was classified as full, partial or no access. Full access was the situation in which people had all medicines needed to care for the disease in the last 30 days; partial, when any medicine was missing due to financial difficulty or unavailability at the Unified Health System (SUS); and no access, when no drugs were obtained in the last 30 days, also due to financial difficulty or unavailability at SUS. The denominator comprised people with medical indication to treat high blood pressure with drugs, excluding cases of intentional abandonment of treatment. Abandonment was defined as cases in which, despite medical indication, people were not using medications for high blood pressure; and cases in which they declared to be using the drugs, but had been without in the last 30 days. In both situations, abandonment cases were restricted to lack of medicines for reasons other than financial difficulty or unavailability at SUS.
Reported medicines for high blood pressure were classified into four groups, according to the reported use for treating high blood pressure. Group 1 consisted of drugs definitely used for high blood pressure, such as diuretics, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers. Group 2 included drugs associated with patients' care with high blood pressure, such as statins and acetylsalicylic acid. Group 3 corresponded to medicines unrelated to high blood pressure treatment, but reported by respondents as used for that disease. Group 4 comprised all teas or other supplements not classified as medicines. This classification was based on high blood pressure treatment guidelines and a review of the literature for some controversial cases in group 2.
The overall results of this analysis include all medications. The drugs analysis relates exclusively to drugs specifically used for high blood pressure treatment (group 1).
In the analysis of drugs used for high blood pressure treatment, fixed-dose combinations were broken down into isolated drugs. For example, for people who used a medicine with a fixed combination of hydrochlorothiazide and amiloride, each one of those drugs was analyzed separately in the evaluations that considered the number of specific drugs for the treatment of high blood pressure.
Pearson' s Chi-square test was used for percentage bivariate comparison, considering p < 0.05 as significant values. This study was approved by the Comissão Nacional de Ética em Pesquisa (CONEP -National Research Ethics Commission) and is registered under number 18947013.6.0000.0008. All interviews were conducted after the respondents or their legal representatives had read and signed the consent form.

RESULTS
Prevalence of self-reported high blood pressure in Brazil was 23.7% (95%CI 22.8-24.6), ranging from 16.3% in the North region to 26.0% in the Southeast region. In the 20-39 age group, prevalence was 6.0%, reaching 59.0% in the 60 or over group (Table 1).
Of the total number of people who reported high blood pressure, 93.8% affirmed having medical indication to treat the disease with medication. This indication ranged from 78.0% in the 20-39 age group to 98.1% in the group aged 60 or over (Table 1).
Among people who reported having indication for drug therapy, 94.6% were using the medication at the time of the interview. Use of medication increased with age. Among Brazilian regions, the North and Northeast regions had the lowest frequency of drug use, while the South and Southeast regions had the highest frequency of use (Table 1) Full access to medicines for high blood pressure care was higher in the South region and lower in the Midwest and Northeast regions. Partial access, i.e., lack of part of the drugs in the previous 30 days, was higher in the Midwest region and lower in the South region. Prevalence of access to all necessary medicines for high blood pressure care was similar between the different economic classes. Failure to obtain any hypertension medication for financial difficulties or unavailability at SUS was very low throughout the country, with minor, non-significant differences between the age groups ( Table 2). Intentional abandonment of treatment reached 10.6% of cases. Of all the medicines reported for use in high blood pressure, group 1 (medicines definitely used to treat high blood pressure) corresponded to 90.5%, group 2 (drugs associated with high blood pressure treatment), to 4.1%, group 3 (drugs not indicated for high blood pressure), to 3.2%, and group 4 (supplements and herbs), to 2.3%. Of medicines used specifically to treat high blood pressure (group 1), 92.4% were single-drug and 7.6% were fixed-dose combinations, the most common being hydrochlorothiazide combined with losartan or atenolol or amiloride. Separately, the most common specific drugs used to treat high blood pressure were, in descending order: hydrochlorothiazide, losartan, captopril, enalapril, amlodipine and atenolol, which corresponded to approximately 81.0% of all reported drugs (Table 3).
Among respondents treated with specific drugs for hypertension, 49.9% used only one drug, 36.1% used two, and 13.5% used three or more drugs (Table 4). High blood pressure treatment with more than one drug increased with age. In the 20 to 39 age group, 43.3% of hypertensive patients used more than one drug, while for those over 60 the figure was 52.2%. Differences were also observed among individuals suffering only from high blood pressure. Of those, 46.0% treated hypertension with more than one drug, and among people with two or more other chronic diseases, 55.8% used more than one drug. In the North region, the use of two or more drugs was lower than that observed in the other Brazilian regions.  Of medicines used to treat high blood pressure, 56.0% were obtained from SUS, 16.0% from Programa Farmácia Popular (program-specific or accredited drugstores) and 2.3% elsewhere. Payment by the actual patients corresponded to 25.7% of medications used to treat this condition.

DISCUSSION
Prevalence of self-reported high blood pressure in this study was 23.7% for all ages, 18.5 in men and 28.1 in women. Barros  When compared with previous population studies, prevalence of self-reported high blood pressure in this study confirms the upward trend of this disease in all age groups. The figures found in the Vigitel survey are higher, probably because this tool included only state capitals and metropolitan areas of Brazil, where prevalence of hypertension tends to be higher, whether due to increased presence of risk factors, greater access to diagnosis or a combination of both factors.
In this study, the question on the use of medicines for high blood pressure was preceded by another question about the existence of medical indication for treatment of high blood pressure with medications. This question was included after the study identified that one of the reasons participants were not using drugs was the lack of medical indication.
Ferreira et al. 11 , analyzing data of the 2008 PNAD 25 , found that 17.0% of patients did not use high blood pressure medication. The study shows that of people with hypertension, 6.2% had no medical indication to treat the disease with medication, and only 5.4% of those with indication were not using the drugs. The difference in the results of both studies may be due the authors assuming that all patients with high blood pressure should use medicines to treat the condition.
Indication for treatment with medication is high. This may reflect late diagnosis, given that in stage 1 hypertension, lifestyle change is the first indication, with drug treatment only introduced six months after that measure fails g . When diagnosis is delayed, greater severity of the disease or less success in the use of non-drug treatment is expected, due to lack of lifestyle changes. A further aspect is the behavior of doctors, who, expecting that patients will not adhere to non-drug treatment, introduce drug treatment alongside lifestyle change recommendations.
Analysis of PNAD h data showed a significant difference in drug use between men and women, with lower rates among men. Data from this study show a slightly lower use among men compared to women and this difference was not significant.
Also consistent are the lower rates of medicine use among younger age groups. This study shows that younger people receive less indication for drug treatment, and when they do, adherence is very low compared to older people. Consequently, young people miss the opportunity to prematurely reduce cardiovascular risks with the use of medicines and may experience further harm in future complications of the clinical condition.
Overall, indication and use of medications were high, which should be considered positive, especially because it is an asymptomatic clinical condition. However, a more accurate The most commonly used drugs were hydrochlorothiazide, followed by losartan, captopril and enalapril. These results are similar to those found in other studies in which diuretics and renin-angiotensin system antagonists are the drugs used to treat high blood pressure 13,22 .
A meta-analysis of 31 randomized controlled trials involving 190,606 participants carried out by the Blood Pressure Lowering Treatment Trialists' Collaboration 8 showed no significant differences between the various drugs used to treat high blood pressure in the prevention of cardiovascular events.
High blood pressure treatment with more than one drug is observed in other countries. In England, 45.0% of patients undertake monotherapy; 36.0%, two drugs; 14.0%, three drugs; and 4.0%, four drugs 10  In short, prevalence of high blood pressure continues to increase among the adult Brazilian population. Access to medicines to treat this disease proved to be quite high. Compared with previous studies, this increase appears to be consistent. Pharmaceutical care public policies may explain this phenomenon. Most of the drugs used are among those recommended in the literature as first-line drugs for high blood pressure treatment. In this study, the number of drugs used shows the same trend observed in the United States and England, i.e., a growth in the number of drugs needed to keep blood pressure under adequate control.
Full access to medicines for high blood pressure can be seen as the first step in the treatment of this clinical condition, but not the only one. About 50.0% of treated patients do not have adequate blood pressure control 16,20 . Access to drugs must be complemented by good adherence to treatment, appropriate management of the drugs for each patient, and control of other factors that may hinder blood pressure control, such as high salt intake or obstructive sleep apnea 21 .