Abstracts

INTRODUCTION

Cardiovascular diseases (arterial hypertension, ischemic and cerebrovascular diseases) are the first cause of morbimortality in the world¹1. Organização Mundial de Saúde. Global status report on noncommunicable diseases 2010. Genebra: WHO; 2011. and are responsible for about 30% of causes of death in Brazil¹1. Organização Mundial de Saúde. Global status report on noncommunicable diseases 2010. Genebra: WHO; 2011.^,22. Schmidt MI, Duncan BB, Silva GA, Menezes AM, Monteiro CA, Barreto SM, et al. Chronic non-communicable diseases in Brazil: burden and current challenges. Lancet 2011; 377(9781): 1949-61.. Among them, hypertension is the most frequent cause of morbidity and the main risk factor for cardiovascular complications, such as stroke and acute myocardial infarction, besides chronic kidney disease¹1. Organização Mundial de Saúde. Global status report on noncommunicable diseases 2010. Genebra: WHO; 2011.^,33. Ribeiro AB. Atualização em hipertensão arterial: clínica, diagnóstico e terapêutica. São Paulo: Atheneu; 2007..

The World Health Organization (WHO) estimates that approximately 25% of the population have arterial hypertension (AH), and an increase of 60% is predicted for 2025¹1. Organização Mundial de Saúde. Global status report on noncommunicable diseases 2010. Genebra: WHO; 2011.^,44. Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet 2005; 365(9455): 217-23.. Besides, AH brings high socioeconomic costs, and directly affects individuals, the health system and the economy⁵5. Balu S, Thomas J 3rd. Incremental expenditure of treating hypertension in the United States. Am J Hypertens 2006; 19(8): 810-6..

Risk factors associated with AH are described in literature, such as inadequate diet, excessive salt, abusive alcohol consumption, physical inactivity, excess weight, smoking, glucose and lipid metabolism disorders³3. Ribeiro AB. Atualização em hipertensão arterial: clínica, diagnóstico e terapêutica. São Paulo: Atheneu; 2007.

4. Kearney PM, Whelton M, Reynolds K, Muntner P, Whelton PK, He J. Global burden of hypertension: analysis of worldwide data. Lancet 2005; 365(9455): 217-23.

5. Balu S, Thomas J 3rd. Incremental expenditure of treating hypertension in the United States. Am J Hypertens 2006; 19(8): 810-6.

6. Ferreira SR, Moura EC, Malta DC, Sarno, F. Frequência de hipertensão arterial e fatores associados: Brasil, 2006. Rev. Saúde Pública 2009; 43(2): 98-106.^-77. Lino MZ, Muniz PT, Siqueira, KS. Prevalência e fatores associados ao excesso de peso em adultos: inquérito populacional em Rio Branco, Acre, Brasil, 2007-2008. Cad Saúde Pública 2011; 27(4): 797-810..

In Brazil, there are a few population based studies referring to the prevalence of AH. Most of them are focused on cities or regions⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.

9. Piccini RX, Victora CG. Hipertensão arterial sistêmica em área urbana no sul do Brasil: prevalência e fatores de risco. Rev Saúde Pública 1994; 28(4): 261-7.

10. Yokota RT, Iser BP, Andrade RL, Santos J, Meiners MM, Assis DM de et al. Vigilância de fatores de risco e proteção para doenças e agravos não transmissíveis em município de pequeno porte, Brasil, 2010. Epidemiol Serv Saúde 2012; 21(1): 55-68.

11. Castro RA, Moncau JE, Marcopito LF. Prevalência de hipertensão arterial sistêmica na cidade de Formiga, MG. Arq Bras Cardiol 2007; 88(3): 334-9.

12. Passos VM, Assis TD, Barreto SM. Hipertensão arterial no Brasil: estimativa de prevalência a partir de estudos de base populacional. Epidemiol Serv Saúde 2006; 15(1): 35-45.^-1313. Barreto SM, Passos VM, Firmo JO, Guerra HL, Vidigal PG, Lima-Costa MF. Hypertension and clustering of cardiovascular risk factors in a community in Southeast Brazil: the Bambuí Health and Ageing Study. Arq Bras Cardiol 2001; 77(6): 576-81.. In general, studies present methodological differences (sample, population groups, age group, and diagnostic criteria) that make comparability more difficult. However, prevalence ranges from 15 to 40% in the urban adult Brazilian population⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.

9. Piccini RX, Victora CG. Hipertensão arterial sistêmica em área urbana no sul do Brasil: prevalência e fatores de risco. Rev Saúde Pública 1994; 28(4): 261-7.

10. Yokota RT, Iser BP, Andrade RL, Santos J, Meiners MM, Assis DM de et al. Vigilância de fatores de risco e proteção para doenças e agravos não transmissíveis em município de pequeno porte, Brasil, 2010. Epidemiol Serv Saúde 2012; 21(1): 55-68.

11. Castro RA, Moncau JE, Marcopito LF. Prevalência de hipertensão arterial sistêmica na cidade de Formiga, MG. Arq Bras Cardiol 2007; 88(3): 334-9.

12. Passos VM, Assis TD, Barreto SM. Hipertensão arterial no Brasil: estimativa de prevalência a partir de estudos de base populacional. Epidemiol Serv Saúde 2006; 15(1): 35-45.

13. Barreto SM, Passos VM, Firmo JO, Guerra HL, Vidigal PG, Lima-Costa MF. Hypertension and clustering of cardiovascular risk factors in a community in Southeast Brazil: the Bambuí Health and Ageing Study. Arq Bras Cardiol 2001; 77(6): 576-81.^-1414. Lessa, I. Hipertensão arterial sistêmica no Brasil: tendência temporal. Cad. Saúde Pública 2010; 26(8): 1470..

Due to the methodological difficulties to measure blood pressure in population studies, analyses that employ self-reported data have been used as a proxy measure, even if it is not gold-standard for the evaluation of blood pressure. However, this is the only available standardized option for all of the capitals, regardless of their respective social discrepancies¹⁴14. Lessa, I. Hipertensão arterial sistêmica no Brasil: tendência temporal. Cad. Saúde Pública 2010; 26(8): 1470..

In the supplement of the National Household Survey (PNAD) from 2008, a frequency of 14% of hypertension was reported among people aged more than 15 years old¹⁵15. Brasil. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios. Um panorama da saúde no Brasil. Acesso e utilização de serviços, condições de saúde e fatores de risco e proteção à saúde 2008. Rio de Janeiro: IBGE; 2010.. In the United States, the Behavioral Risk Factor Surveillance System (BRFSS) used the self-reported methodology to monitor AH for more than 20 years¹⁶16. Centers for Disease Control and Prevention. Behavioral Risk Factor Surveillance System (BRFSS) [Internet]. Disponível em: http://www.cdc.gov/BRFSS/ (Acessado em 20 de janeiro de 2008).
http://www.cdc.gov/BRFSS/... .

The prevalence of self-reported hypertension in the United States, from 2005 to 2009, increased from 25.8 to 28.3%, according to data from BRFSS¹⁷17. Centers for Disease Control and Prevention. Self-Reported Hypertension and Use of Antihypertensive Medication Among Adults - United States, 2005-2009. Morb Mortal Wkly Rep 2013; 62(13): 237-44.. A systematic review with data published from January 1980 to July 2003 indicates that the prevalence of hypertension is different around the world: the lowest prevalence was in the rural region of India (5.2%), and the highest one was in Poland (70.7%)¹⁸18. Kearney PM, Whelton M, Reynolds K, Whelton PK, He J. Worldwide prevalence of hypertension: a systematic review. J Hypertens 2004; 22(1): 11-19..

The monitoring of AH is useful to support the elaboration of preventive measures of morbimortality for this group of cardiovascular diseases. In 2006, the Ministry of Health implemented Vigitel - Telephone-Based Surveillance of Risk and Protective Factors for Chronic Diseases - an instrument that monitors the distribution of risk and protective factors for non-communicable chronic diseases, including self-reported arterial hypertension, using telephone interviews¹⁹19. Brasil. Secretaria de Vigilância em Saúde, Ministério da Saúde. VIGITEL 2011: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília (DF): Ministério da Saúde; 2012..

The objective of this study is to estimate the prevalence of self-reported AH in the adult population in 2011 in Brazilian capitals and in the Federal District, and also to analyze the trend in the period from 2006 to 2011.

METHODS

TYPE OF STUDY

A study of time series database with data originated from the Telephone-Based Surveillance of Risk and Protective Factors for Chronic Diseases (Vigitel) was conducted in the 26 Brazilian capitals and in the Federal District from 2006 to 2011. Annually, about 2,000 telephone interviews were collected in each of the 26 Brazilian capitals and in the Federal District, accounting for 54,000 individuals assessed every year¹⁹19. Brasil. Secretaria de Vigilância em Saúde, Ministério da Saúde. VIGITEL 2011: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília (DF): Ministério da Saúde; 2012..

SAMPLE

Vigitel uses the probability sample in two stages:

The estimates of indicators were weighed by considering the differences in the probability of selecting each interviewee, characterized according to the number of landlines and adults living in the selected household, as well as the differences in the sociodemographic composition of the Vigitel sample in relation to the composition of the total adult population in each city, according to the census distribution of 2000. Final weights are attributed to each interviewed individual, which are a result of the multiplication of the following factors: the opposite of the number of landlines in the household of the interviewee; number of adults in the interviewed household; and post-stratification weight, which aims at equaling the sociodemographic composition of the adult population in the city with the population census, according to data of sex, age groups and schooling. A forth weighing factor is used for the estimates related to the set of the 27 capitals, being the ratio between the proportion of adults in a given city by the proportion of adults in the 27 cities¹⁹19. Brasil. Secretaria de Vigilância em Saúde, Ministério da Saúde. VIGITEL 2011: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília (DF): Ministério da Saúde; 2012..

STUDIED VARIABLES

The current study analyzed data referring to the prevalence of arterial hypertension, based on the number of individuals that refer to the medical diagnosis of arterial hypertension/interviewed individuals, according to the answer given to the question "Has any doctor ever told you have high blood pressure?".

STATISTICAL ANALYSIS

The tendency measure of the time series of AH was stratified according to sex, age group, schooling and region of the country. The indicator was expressed by the proportion of adults who answered yes to the question concerning AH for each year of the survey. The technique used to estimate the tendency was the polynomial regression model, whose response variable (Y_i) is the proportion of the indicator, and the explanatory variable (X_i) is time (year of survey). The negative signal of the angular coefficient (β) of the line adjusted by the model indicates that the relationship between indicator and time is decreasing; otherwise, the relationship is increasing. The value of the positive angular coefficient represents a mean annual increase in the proportion of the indicator for each unit of time. Otherwise, it represents the mean annual decrease of the proportion²⁰20. Bussab WO, Morettin PA. Estatística básica. 5a ed. São Paulo: Saraiva; 2006..

The proportions for the period of 2006 to 2011 were presented, as well as the tendency expressed by the angular coefficient of the line and the significance level of the tendency. The residue analysis was used, with a 5% significance level, as measures of model adequacy. For data processing and statistical analyses, the software Stata, version 11.1, was used. The commands indicated for proportions were used, considering the weighing factors attributed to each individual who was interviewed in Vigitel surveys¹⁹19. Brasil. Secretaria de Vigilância em Saúde, Ministério da Saúde. VIGITEL 2011: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília (DF): Ministério da Saúde; 2012..

ETHICAL ASPECTS

This study was approved by the National Human Ethics Research Committee (CONEP). The informed consent form was replaced by the verbal consent, obtained during telephone contacts with the interviewees.

RESULTS

In the set of the adult population of the 27 cities analyzed in 2011, the frequency of a previous medical diagnosis of arterial hypertension reached 22.7% (95%CI 21.9 - 23.5), being higher among women (25.4%; 95%CI 24.2 - 26.5) than men (19.5%; 95%CI 18.4 - 20.7) (Table 1). The prevalence of adults who reported a medical diagnosis of arterial hypertension in 2011 ranged between 12.9% (95%CI 10.2 - 15.6) in Palmas and 29.8% (95%CI 27.0 - 32.6) in Rio de Janeiro. For the male gender, the highest frequencies were observed in Rio de Janeiro (23.9%; 95%CI 20.0 - 27.9), Campo Grande (23.9%; 95%CI 19.5 - 28.3) and Porto Alegre) 23.6%; 95%CI 19.8 - 27.5); lowest frequencies were observed in Porto Velho (12.9%; 95%CI 10.3 - 15.5), Palmas (13.1%; 95%CI 8.8 - 17.4) and Fortaleza (14.3%; 95%CI 11.2 - 17.4). Among women, the highest frequencies were observed in Rio de Janeiro (34.7%; 95%CI 31.0 - 38.4), Recife (30.3%; 95%CI 26.5 - 34.1) and Natal (28.2%; 95%CI 24.0 - 32.4); lowest frequencies were in Palmas (12.7%; 95%CI 9.4 - 16.0), Boa Vista (18.4%; 95%CI 14.0 - 22.8) and São Luís (19.1%; 95%CI 15.0 - 23.2). The capitals that presented significant differences in prevalence between men and women were Porto Velho, Recife and Rio de Janeiro (Table 1).

In the period of 2006 to 2011, the frequency of reported arterial hypertension among adults analyzed by Vigitel ranged from 21.5% in 2006 and 24.4% in 2009. Howver, there was no statistically significant difference in all of the analyzed period. Likewise, no specific significant tendency was observed by sex. The highest frequency of hypertension among women was observed in all of the analyzed years (Table 2).

It was possible to verify progressive increase in the frequency of hypertension diagnosis with age, and the prevalence among the elderly (65 years old or more) was up to 10 times higher than that among young adults (18 to 24 years old). In 2011, for instance, the prevalence was of 5.4% for the former and 59.7% for the latter. This relationship was observed in all of the years of the series, with no time tendency of changes in the period. From the age of 55, arterial hypertension reaches practically half of the population (Table 2).

It is important to mention the inverse association between schooling and the diagnosis of the disease: while 26.8% of the people, with up to eight schooling years, reported having arterial hypertension, the same condition was observed among 16.0% of the adults with 12 schooling years or more. These differences between schooling categories remained in 2011 (28.3 and 17.5%, respectively), also with no changes of tendency in the period.

In the evaluation of prevalence according to regions of the country, it was possible to notice that the highest frequencies were observed in the Southeast (prevalence of 24.7% in 2011), and the lowest ones were in the North region (18.8%), and this situation was similar to the previous years. The South region showed statistically significant increasing tendency with non-constant increment of 0.47 a year, going from 20.9%, in 2006, to 23.1%, in 2011 (p = 0.044). The Northeast and Center-West regions presented 21.1% of prevalence in 2011 (Figure 1).

The third order model represented the historical series of 2006 to 2011, with no difference of sex and age group. It was observed that the mean coefficient was of 18.1% in the Southeast region, while the highest coefficient was in the North region in the same period (β₀= 22.6). The South region was the only one that presented statistically significant increasing tendency (15% increment a year), however, it was not constant for the years 2006 to 2011 (Figure 1).

DISCUSSION

The study showed prevalence of arterial hypertension (AH) in about one quarter of the population, with progressive increase with age, reaching more than half of the population aged more than 55 years old. Self-reported AH was more frequent among women and people with lower schooling. As to the behavior of the hypertension tendency, the series remained stable throughout the period for the characteristics of sex, age group, schooling and region, except for the South region, which demonstrated an increasing effect in the analyzed series.

Hypertension is the most comprehensive vascular disease in the world, with major social impact, especially in Brazil, where cardiovascular conditions are the first cause of death. The prevalence measured by Vigitel is compatible with other self-reported studies in the country⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.^,99. Piccini RX, Victora CG. Hipertensão arterial sistêmica em área urbana no sul do Brasil: prevalência e fatores de risco. Rev Saúde Pública 1994; 28(4): 261-7.^,1212. Passos VM, Assis TD, Barreto SM. Hipertensão arterial no Brasil: estimativa de prevalência a partir de estudos de base populacional. Epidemiol Serv Saúde 2006; 15(1): 35-45.^,1414. Lessa, I. Hipertensão arterial sistêmica no Brasil: tendência temporal. Cad. Saúde Pública 2010; 26(8): 1470..

Regional differences were pointed out and, in some capitals, prevalence rates are very different. Rio de Janeiro presented the highest prevalence (29.8%) among Brazilian capitals. This information is similar to the results in the Pró-Saúde study, conducted in a university of Rio de Janeiro, in 2001. This study showed 29.6% for both genders and statistically significant increase in prevalence with age²¹21. Nogueira D, Faerstein E, Coeli CM, Chor D, Lopes CS, Werneck GL. Reconhecimento, tratamento e controle da hipertensão arterial: Estudo Pró-Saúde, Brasil. Rev Panam Salud Publica 2010; 27(2): 103-9.. This fact is compatible with the age structure of Rio de Janeiro, with high proportion of elderly people²²22. Brasil. Instituto Brasileiro de Geografia e Estatística. Sinopse do Censo Demográfico 2010. Rio de Janeiro: IBGE; 2011..

On the other hand, the city of Palmas presented the lowers prevalence among all cities (12.9%), and that can be related to the high proportion of the young population in the city, which was created in the 1980s²²22. Brasil. Instituto Brasileiro de Geografia e Estatística. Sinopse do Censo Demográfico 2010. Rio de Janeiro: IBGE; 2011.^,2323. Schmidt MI, Ducan BB, Hoffmann JF, Moura L, Malta DC, Carvalho RM. Prevalência de diabetes e hipertensão no Brasil baseada em inquérito de morbidade auto-referida, Brasil, 2006. Rev Saúde Pública 2009; 43(2): 74-82.. The North, Northeast and Center-West regions also have more young people in the composition of the population; therefore, there is lower prevalence of AH. The regional differences should also be considered for the access to health services. Since this is a self-reported variable, there may be a fraction of undiagnosed cases of hypertension, which tends to be reduced with the amplified access to health services and with the organization of primary care.

This same hypothesis can explain the highest frequencies of AH in the population of the Southeast and the South, with older population and better health care structure, both from the public and the private sector, for the access to the medical diagnosis of AH. According to PNAD from 2008¹⁵15. Brasil. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios. Um panorama da saúde no Brasil. Acesso e utilização de serviços, condições de saúde e fatores de risco e proteção à saúde 2008. Rio de Janeiro: IBGE; 2010., 50.3% of the permanent private households in the South region were registered in the Family Health Program, and 30% of their inhabitants declared having an insurance health plan. Additionally, the population aging in the South region could also explain the increasing tendency in the prevalence of hypertension in this location. Census 2010 pointed out that 8.1% of the population in this region is composed of people aged 65 years old or more²²22. Brasil. Instituto Brasileiro de Geografia e Estatística. Sinopse do Censo Demográfico 2010. Rio de Janeiro: IBGE; 2011..

With regard to schooling, the relationship was opposite, thus showing that educational level, proxy of socioeconomic condition, constitutes a protective factor for the risk of NCCDs. It is related to the higher access to health promotion practices, such as healthy diet and physical activity, and also to the higher access to health services¹1. Organização Mundial de Saúde. Global status report on noncommunicable diseases 2010. Genebra: WHO; 2011.^,66. Ferreira SR, Moura EC, Malta DC, Sarno, F. Frequência de hipertensão arterial e fatores associados: Brasil, 2006. Rev. Saúde Pública 2009; 43(2): 98-106.^,2424. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, et al. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension 2003; 42(6): 1206-52.^,2525. Ferreira AD, César CC, Malta DC, Souza AA, Ramos CG, Proietti FA et al. Validade de estimativas obtidas por inquérito telefônico: comparação entre VIGITEL 2008 e inquérito Saúde em Beagá. Rev Bras Epidemiol 2011; 14(1): 16-30.. However, literature reports that AH has been inversely associated with the schooling of the adult population in São Paulo. Despite that, self-reported AH demonstrated to be an adequate indicator for the surveillance of this disease²⁶26. Selem SS, Castro MA, César CL, Marchioni DM, Fisberg RM. Validade da hipertensão autorreferida associa-se inversamente com escolaridade em brasileiros. Arq Bras Cardiol 2013; 100(1): 52-9..

The World Health Organization (WHO) indicates that the prevalence of hypertension is higher in low and mid-income countries. However, what generates the decreased prevalence of this disease in high income countries are interventions in the public health field²⁷27. Organização Mundial de Saúde. World health statistics 2012. Genebra: WHO; 2012.. In order to reach the objective of a 25% relative reduction in the prevalence of high blood pressure, interventions are required to reduce the intake of salt and saturated fat, and also to increase the intake of fruits and vegetables. Efforts to reduce overweight and obesity as well as screening to detect and treat hypertensive people early are also necessary²⁸28. Organização Mundial de Saúde. Prevention and control of non communicable diseases. Formal meeting of Member States to conclude the work on the comprehensive global monitoring framework, including indicators, and a set of voluntary global targets for the prevention and control of non communicable diseases. Report by the Director-General. Genebra: WHO; 2012..

The study demonstrated higher frequency of AH among women, which is different from data from WHO for 2008. The latter shows that for adults older than 25 years old, the highest prevalence is among men, both in the world (29.2% for men and 24.8% for women) and in the American region (26.3% for men and 19.7% for women)²⁷27. Organização Mundial de Saúde. World health statistics 2012. Genebra: WHO; 2012.. The difference between sexes in the prevalence of hypertension can be explained by the diversity of risk factors among men and women. A plausible explanation is that women recognize their condition of being hypertensive more than men²¹21. Nogueira D, Faerstein E, Coeli CM, Chor D, Lopes CS, Werneck GL. Reconhecimento, tratamento e controle da hipertensão arterial: Estudo Pró-Saúde, Brasil. Rev Panam Salud Publica 2010; 27(2): 103-9., since they attend health services more often⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.^,1212. Passos VM, Assis TD, Barreto SM. Hipertensão arterial no Brasil: estimativa de prevalência a partir de estudos de base populacional. Epidemiol Serv Saúde 2006; 15(1): 35-45.^,2424. Chobanian AV, Bakris GL, Black HR, Cushman WC, Green LA, Izzo JL Jr, et al. Seventh report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure. Hypertension 2003; 42(6): 1206-52..

The main limitation of this study refers to the use of self-reported morbidity to the detriment of biomedical criteria to diagnose the disease. Therefore, the presented data concern only diagnosed cases. Despite the self-reported information, which, in the case of arterial hypertension, may be overestimated in up to 10%, this measure has been used in other studies and has been considered to be adequate⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.^,2525. Ferreira AD, César CC, Malta DC, Souza AA, Ramos CG, Proietti FA et al. Validade de estimativas obtidas por inquérito telefônico: comparação entre VIGITEL 2008 e inquérito Saúde em Beagá. Rev Bras Epidemiol 2011; 14(1): 16-30., with similar results¹⁵15. Brasil. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional por Amostra de Domicílios. Um panorama da saúde no Brasil. Acesso e utilização de serviços, condições de saúde e fatores de risco e proteção à saúde 2008. Rio de Janeiro: IBGE; 2010.^,1919. Brasil. Secretaria de Vigilância em Saúde, Ministério da Saúde. VIGITEL 2011: vigilância de fatores de risco e proteção para doenças crônicas por inquérito telefônico. Brasília (DF): Ministério da Saúde; 2012.. Therefore, the high level of awareness of the population about their hypertensive state showed good access to health services and good AH detection⁶6. Ferreira SR, Moura EC, Malta DC, Sarno, F. Frequência de hipertensão arterial e fatores associados: Brasil, 2006. Rev. Saúde Pública 2009; 43(2): 98-106..

In the United States, a study comparing self-reported AH results in the telephone survey, Behavioral Risk Factor Surveillance System (BRFSS), and the National Health and Nutrition Examination Survey III, which measures blood pressure, point out to good sensitivity and specificity when it comes to measures¹⁶16. Centers for Disease Control and Prevention. Behavioral Risk Factor Surveillance System (BRFSS) [Internet]. Disponível em: http://www.cdc.gov/BRFSS/ (Acessado em 20 de janeiro de 2008).
http://www.cdc.gov/BRFSS/... ^,2929. Centers for Disease Control and Prevention. NHANES III. National Health and Nutrition Examination Survey [Internet]. Disponível em: http://www.cdc.gov/nchs/about/major/nhanes/nh3data.htm (Acessado em 20 de janeiro de 2008).
http://www.cdc.gov/nchs/about/major/nhan... . The study demonstrated that arterial hypertension increased with age, which was compatible with literature due to the natural history of the disease and the accumulation of risk factors³3. Ribeiro AB. Atualização em hipertensão arterial: clínica, diagnóstico e terapêutica. São Paulo: Atheneu; 2007.^,2121. Nogueira D, Faerstein E, Coeli CM, Chor D, Lopes CS, Werneck GL. Reconhecimento, tratamento e controle da hipertensão arterial: Estudo Pró-Saúde, Brasil. Rev Panam Salud Publica 2010; 27(2): 103-9.. For hypertension, literature showed that self-reporting is a satisfactory indicator for prevalence estimates, with the advantage of obtaining information fast and with low cost⁸8. Lima-Costa MF, Peixoto SV, Firmo JO. Validade da hipertensão arterial auto-referida e seus determinantes (projeto Bambuí). Rev Saúde Pública 2004; 38(5): 637-42.^,3030. Vargas CM, Burt VL, Gillum RF, Pamuk ER. Validity of self-reported hypertension in the National Health and Nutrition Examination Survey III, 1988-1991. Prev Med 1997; 26(5 Pt 1): 678-85..

Another study limitation consisted of the use of landlines in the capitals for purposes of raffle. In the metropolitan South, Southeast and Center-West regions, with more than 70% of coverage, vices due to the exclusion of households without landlines can be unconsidered³¹31. Bernal R, Silva NN. Cobertura de linhas telefônicas residenciais e vícios potenciais em estudos epidemiológicos. Rev Saúde Pública 2009; 43(3): 421-6.. However, the North and Northeast regions presented coverage rates that were lower than 70%. In order to correct the potential vices due to the low coverage of households with landlines, Vigitel used the cell weighing method according to sex, age and schooling, therefore adjusting the distribution of the sample to the characteristics of the population living in each capital (according to the census by IBGE). With that, it was possible to reduce the differences between population with and without landlines¹⁴14. Lessa, I. Hipertensão arterial sistêmica no Brasil: tendência temporal. Cad. Saúde Pública 2010; 26(8): 1470.^,3131. Bernal R, Silva NN. Cobertura de linhas telefônicas residenciais e vícios potenciais em estudos epidemiológicos. Rev Saúde Pública 2009; 43(3): 421-6..

Other comparative studies between data from Vigitel and household surveys indicated the importance of weighing to reduce vice in some variables, especially those associated with low income and low schooling³²32. Francisco PM, Barros MB, Segri NJ, Alves MC, Cesar CL, Malta DC. Comparison of estimates for the self-reported chronic conditions among household survey and telephone survey--Campinas (SP), Brazil. Rev Bras Epidemiol 2011; 14(1): 5-15.^,3535. Nações Unidas. Political declaration of the high-level meeting of the General Assembly on the prevention and control of non-communicable diseases. UN General Assembly A/66/L.1. 2011.. The monitoring of Vigitel data makes it possible to analyze tendencies, even though the six-year time for analysis is short to provide a more robust description of tendency, therefore, there may be changes in the historical series.

It is also important to mention the monitoring NCCDs and their risk factors as part of the promises made by Brazil, especially in the plan to face the NCCDs and in national and international goals and those established to reduce the mortality of NCCDs, the reduction of arterial hypertension and the control of risk patients, keeping them in control programs²⁸28. Organização Mundial de Saúde. Prevention and control of non communicable diseases. Formal meeting of Member States to conclude the work on the comprehensive global monitoring framework, including indicators, and a set of voluntary global targets for the prevention and control of non communicable diseases. Report by the Director-General. Genebra: WHO; 2012.^,3333. Brasil. Ministério da Saúde. Plano de ações estratégicas para o enfrentamento das doenças crônicas não transmissíveis (DCNT) no Brasil, 2011-2022. Brasília (DF): Ministério da Saúde; 2011.

34. Malta DC, Morais Neto OL, Silva Junior JB. Apresentação do plano de ações estratégicas para o enfrentamento das doenças crônicas não transmissíveis no Brasil, 2011 a 2022. Epidemiol Serv Saúde 2011; 20(4): 425-38.

35. Nações Unidas. Political declaration of the high-level meeting of the General Assembly on the prevention and control of non-communicable diseases. UN General Assembly A/66/L.1. 2011.^-3636. Organização Mundial de Saúde. 65th World Health Assembly closes with new global health measures [Internet]. Disponível em: http://www.who.int/mediacentre/news/releases/2012/wha65_closes_20120526/en/index.html (Acessado em 30 de maio de 2012).
http://www.who.int/mediacentre/news/rele... . However, by considering the complexity and the difficult logistics of regular household surveys with objective measures of blood pressure, information resulting from Vigitel can contribute with planning, monitoring and evaluation of national actions for its control.

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