BUENOS AIRES, Argentina — Simplified methods for measuring blood pressure that are based on two or even one single measurement instead of the recommended three can be reasonably trustworthy and more efficient for detecting hypertension in large populations, concludes a new study published in PLOS Medicine.
“In practical terms, the results open the possibility of using a simplified method to save time in screening for hypertension in programs for thousands or millions of people. And they may also be used in very busy health services as initial screening,” first author Rodrigo Carrillo-Larco, MD, of the Department of Epidemiology and Biostatistics of the School of Public Health, Imperial College London, United Kingdom, told Medscape Spanish Edition.
For screening, the standard method for accurately measuring blood pressure measurement involves measuring the blood pressure three times at 3-minute intervals and using the average of the latter two. Arterial hypertension is defined as a systolic blood pressure of ≥140 mm Hg or a diastolic pressure of ≥ 90 mm Hg, stated Carrillo-Larco, who is also an associate researcher of CRONICAS Center for Excellence in Chronic Diseases of the Cayetano Heredia Peruvian University, in Lima.
“Since this procedure requires a minimum of 6 minutes per participant, we are surprised that no global studies exist that evaluate simplifying the method, even though this can save time and therefore screen more people,” he stated.
To explore this gap in knowledge, researchers analyzed World Health Organization (WHO) STEPS surveys at the population level. These surveys included 145,174 individuals (average age, 35 to 45 years) in 60 countries, among them Ecuador and Uruguay. The data included the three blood pressure measurements of each participant, in addition to their anthropometric information and information on the consumption of tobacco, fasting glycemia, and total cholesterol level.
The researchers estimated the consistency between the eventual diagnoses from various simplified methods and those from the standard method. They calculated in each case how many cases may have been missed (ie, cases in which patients did not receive a diagnosis of arterial hypertension when it would have been detected with the method of reference) and how many patients could have been overdiagnosed.
Results May Prompt Discussion
The findings were encouraging, both globally and in the regions and countries studied. Across all countries, compared with the standard approach, the simplified approach that missed the fewest cases (5.6%) used the second blood pressure reading if the first blood pressure reading was 130–145/80–95 mm Hg. This was followed by the approach that considered the second reading independently of the first (5.8%).
Conversely, using only the second determination if the first was ≥140/90 mm Hg missed 15% of patients with hypertension (ie, it did not detect these patients as having hypertension), but this is the method with the smallest rate of overdiagnosis: 3.03% globally. Using only the second reading if the first measurement was ≥140/90 mm Hg led to overdiagnosis, which at a country level was between 1% and 11%. The authors consider that this simplified method offers the most “reasonable” proportion of underdiagnosis and overdiagnosis.
“The results indicate that the simplified methods may be useful and provide an alternative for hypertension screening to reach more people. These results may start the discussion about the simplified methods and, if necessary, motivate validations in each country to choose the best protocol,” co-author Wilmer Guzman-Vilca, a medical student and member of CRONICAS and the Scientific Society of Medical Students at Cayetano Heredia, in Lima, Peru, told Medscape Spanish Edition.
Using regression models and the available data from the surveys in 54 countries, the researchers noted that the cardiovascular risk after 10 years for patients with hypertension whose cases were missed with the simplified methods was slightly lower than that of their peers whose hypertension was detected, which serves as an additional reassurance. “However, this observation deserves greater exploration, including prospective studies,” said Guzman-Vilca.
According to the researchers, using simplified methods for blood pressure measurement with two determinations instead of three could allow for the screening of 20 people per hour instead of 10 per hour, which could be useful in large campaigns and in clinics that lack sphygmomanometers or personnel, especially in low- or medium-income countries.
“The spread of the reliability of a simplified method could help the conduct of screening campaigns that would benefit hundreds or thousands of people,” said Carrillo-Larco. “Likewise, they could promote that screenings be conducted in busy health establishments, and the treating physician could thus decide the following steps, such as a new measurement following the clinical diagnostic guidelines or the use of other instruments, such as measurement at home, as required in each case.” Carrillo-Larco stressed that the results of the study are applicable for screening, not for starting treatment or for the follow-up of patients with hypertension. “It is still premature for these indications.”
Two Great Problems
The new study also functions as a guarantee for countries that, because of time or personnel restrictions, currently conduct population screening campaigns using two or even one determination per person instead of the recommended three. It may also allow them to adjust their diagnoses, as in Argentina. When in 2017, the Argentine Society of Arterial Hypertension (SAHA) joined the global campaign of May Measurement Month (MMM) of the International Society of Hypertension (ISH), its authorities considered it impractical for participants to answer a 28-question survey and have their blood pressure taken on three occasions. The MMM campaign has benefited more than one million people in hundreds of countries.
“We decided that the survey would only include nine questions and that blood pressure be taken two times, averaging the results,” Marcos Marín, MD, chair of the SAHA and ex-coordinator of the SAHA’s Know and Control Your Blood Pressure campaign, told Medscape Spanish Edition.
“We asked the ISH if this would work, and they said yes. There are countries that only took one blood pressure reading. It is not ideal, but it was an awareness campaign,” said Marín. SAHA’s Know and Control Your Blood Pressure campaign screened 98,000 people in 2019 alone. This total was “the third country in the world by amount,” said Marín.
In addition to the very low level of monitoring, lack of awareness is one of the two great problems, stated Marín. “Four out of every 10 people with hypertension do not know they have it.” In addition to increasing the specific campaigns of population screening, more doctors need to take blood pressure in an appropriate way during the consultation, he said.
Marín is a co-author of the recently published Argentine Registry of Blood Pressure Measurement in the Consultation (RAMPAC) study. In that study, researchers analyzed all outpatient consultations conducted one day in September 2019 at nine health centers. It revealed that in only 14.1% of the consultations did doctors conduct that measurement. “There is a lot of work to do,” concluded Marín.