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Impact of Different Normality Thresholds for 24-hour ABPM at the Primary Health Care Level
Guilherme Brasil Grezzana1, David William Moraes2, Airton Tetelbon Stein2,3
1Instituto de Cardiologia - Fundação Universitária de Cardiologia; Porto Alegre, RS - Brazil.
Insights
Primary care physicians
Area of Science:
- Cardiology
- Primary Health Care
- Hypertension Management
Background:
- Hypertension is a significant risk factor for cardiovascular events.
- Low rates of controlled blood pressure (BP) highlight challenges in primary care.
- 24-hour ambulatory BP monitoring (ABPM) may reclassify hypertension, impacting clinical decisions.
Purpose of the Study:
- To assess the agreement between conventional BP measurements by primary health care (PHC) physicians and 24-hour ABPM.
- To compare agreement using different BP normal thresholds from Brazilian and European hypertension guidelines.
Main Methods:
- Cross-sectional study with 569 hypertensive patients.
- Independent BP measurements using conventional methods and 24-hour ABPM.
- Adherence to JNC 8, V Brazilian ABPM Guidelines, and 2013 European Hypertension Guidelines for therapeutic targets.
Main Results:
- Conventional BP measurements showed low accuracy (54.8%) compared to 24-hour ABPM using European guidelines.
- Sensitivity was 85% and specificity 31.9% with a kappa of 0.155.
- Using stricter ABPM thresholds reduced accuracy to 45%, with sensitivity 86.7% and specificity 29%.
Conclusions:
- Conventional BP measurements by PHC physicians exhibit low accuracy compared to 24-hour ABPM.
- This discrepancy persists regardless of the specific guideline thresholds used.
- Implications for accurate hypertension diagnosis and management in primary care settings.
Background::
Hypertension is an important risk factor for cardiovascular outcomes. Primary health care (PHC) physicians should be prepared to act appropriately in the prevention of cardiovascular risk factors. However, the rates of patients with control of blood pressure (BP) remain low. The impact of the reclassification of high BP by 24-hour ambulatory BP monitoring (ABPM) can lead to different medical decisions in PHC.
Objective::
To evaluate the agreement between the BP measured by a conventional method by PHC physicians and by 24-hour ABPM, considering different BP normal thresholds for the 24-hour ABPM according to the V Brazilian ABPM Guidelines and the European Society of Hypertension Guidelines.
Methods::
A cross-sectional study including 569 hypertensive patients. The BP was initially measured by the PHC physicians and, later, by 24-hour ABPM. The BP measurements were obtained independently between the two methods. The therapeutic targets for the conventional BP followed the guidelines by the Eighth Joint National Committee (JNC 8), the V ABPM Brazilian Guidelines, and the 2013 European Hypertension Guidelines.
Results::
There was an accuracy of 54.8% (95% confidence interval [95%CI] 0.51 - 0.58%) for the BP measured with the conventional method when compared with the 24-hour ABPM, with a sensitivity of 85% (95%CI 80.8 - 88.6%), specificity of 31.9% (95%CI 28.7 - 34.7%), and kappa value of 0.155, when considering the European Hypertension Guidelines. When using more stringent thresholds to characterize the BP as "normal" by ABPM, the accuracy was 45% (95%CI 0.41 - 0.47%) for conventional measurement when compared with 24-hour ABPM, with a sensitivity of 86.7% (95%CI 0.81 - 0.91%), specificity of 29% (95%CI 0.26 - 0.30%), and kappa value of 0.103.
Conclusion::
The BP measurements obtained by PHC physicians showed low accuracy when compared with those obtained by 24-hour ABPM, regardless of the threshold set by the different guidelines.
Fundamentos::
A hipertensão arterial sistêmica é um fator de risco importante para desfechos cardiovasculares. Médicos da atenção primária à saúde (APS) devem estar preparados para atuar adequadamente na prevenção de fatores de risco cardiovascular. No entanto, as taxas de pacientes com pressão arterial (PA) controlada continuam baixas. O impacto da reclassificação do diagnóstico de hipertensão pela utilização da monitorização ambulatorial da PA (MAPA) de 24 horas pode levar a diferentes decisões médicas na APS.
Objetivo::
Avaliar a concordância entre as PAs medidas por método convencional por médicos da APS e por MAPA de 24 horas, considerando diferentes limiares de normalidade para a MAPA de 24 horas de acordo com as recomendações da V Diretriz Brasileira de MAPA e da Diretriz da Sociedade Europeia de Hipertensão.
MéTodos::
Estudo transversal com 569 pacientes hipertensos. A PA foi medida inicialmente por médicos da APS e, posteriormente, pela MAPA de 24 horas. As medidas foram obtidas de forma independente entre os dois métodos. Os alvos terapêuticos para a PA convencional seguiram as orientações do Eighth Joint National Committee (JNC 8), das V Diretrizes Brasileiras de MAPA e das Diretrizes Europeias de Hipertensão de 2013.
Resultados::
Foi observada uma acurácia de 54,8% (intervalo de confiança de 95% [IC95%] 0,51 - 0,58%) para a PA aferida de forma convencional quando comparada à obtida com a MAPA de 24 horas, além de uma sensibilidade de 85% (IC95% 80,8 - 88,6%), especificidade de 31,9% (IC95% 28,7 - 34,7%) e kappa de 0,155, quando consideradas as Diretrizes Europeias de Hipertensão. Quando utilizados limiares mais rígidos para caracterizar a PA como "normal" pela MAPA, foi identificada uma acurácia de 45% (IC95% 0,41 - 0,47%) pela medida convencional quando comparada à obtida pela MAPA de 24 horas, além de uma sensibilidade de 86,7% (IC95% 0,81 - 0,91%), especificidade de 29% (IC95% 0,26 - 0,30%) e kappa de 0,103.
ConclusãO::
As medidas de PA avaliadas pelos médicos da APS apresentaram baixa acurácia quando comparadas às medidas pela MAPA de 24 horas, independente do limiar utilizado pelas diferentes diretrizes.
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