More research needed for optimal hypertension screening and confirmatory algorithms
Screening for Hypertension in Adults – Updated Evidence Report and Systematic Review for the US Preventive Services Task Force
Introduction and methods
Screening for hypertension using office measurements among adults is standard of care in the US , but associated with misclassification of individuals (white coat or masked hypertension). Out-of-office or novel office-based measurement techniques may provide potential benefits.
This systematic review was performed to provide an update of the 2015 US Preventive Service Task Force (USPSTF) recommendations on screening for hypertension in adults . It addressed the benefits and harms of screening, tested accuracy of office-based screening measurements, and methods of confirmatory BP measurements in those with a positive result at screening.
Differences in scope of this update compared to that of the 2015 review were: analysis of specificity and sensitivity of hypertension screening and confirmation, requirement of ambulatory BP measurement as reference standard, inclusion of diabetes patients and no reporting of prognosis associated with various BP measurement modalities.
Eligible studies had to enroll untreated adults or stratify results by treatment status and to be conducted in countries rated as ‘very high’ on the 2015 Human Development Index. 52 Studies were included.
- There was 1 good-quality community-based cluster RCT of 140,642 individuals in Canada that examined the effectiveness of a multicomponent CVD health promotion program on CVD health outcomes with hypertension screening as primary intervention . At 1 year follow-up, the intervention communities had a reduction in number of hospitalization admissions per 1000 persons for composite events compared to the control communities (rate ratio 0.91, 95%CI: 0.86=0.97). And hospital admissions for CVD per 1000 persons were reduced in the intervention group compared to the control group.
- 20 Fair-to good-quality studies (n=12614) examined the test accuracy of OBPM for initial screening for hypertension compared with ABPM. Using studies with SBP/DBP thresholds and measuring BP at a single visit-resulted in a meta-analysis of 15 studies (n=11309) and showed a pooled sensitivity of 0.54 (95%CI: 0.37-0.70) and pooled specificity of 0.90 (95%CI: 0.84-0.95). Positive predictive values and negative predictive values ranged widely, from 0.35 to 0.97 and from 0.25 to 0.97, respectively. False-positive and false-negative rates ranged widely (false-positive rate range 0-30%, false-negative rate range 8-100%).
- 18 Fair-to-good-quality studies (n=57128) examined the diagnostic accuracy of confirmatory BP measurements compared with an ABPM reference-hource standard in adults with a previously detected elevated OBPM. Four confirmatory BP measurement modalities were examined for this question: repeated office BP measurement (repeat OBPM), twice-daily home BP measurement for 3 to 7 days (HBPM), measurement performed by a patient in the office setting (self-OBPM), and a truncated 6-hour ambulatory BP measurement (truncated ABPM).
- Repeat OBPM: Meta-analysis of 8 OBPM confirmation studies (n=53,183) reporting SBP/DBP thresholds showed a pooled sensitivity of 0.80 (95CI% 0.68-0.88) and a pooled specificity of 0.55 (95%CI: 0.42-0.66) with high heterogeneity. Positive predictive values ranged from 0.61-0.88 and negative predictive values from 0.30-0.82. False-positive rates ranged from 15-65% and false-negative rates from 10-65%.
- HBPM: Four studies (n=1001) examined HBPM as a confirmatory method. Meta-analysis of these 4 studies showed a pooled sensitivity of 0.84 (95%CI: 0.76-0.90) and a pooled specificity of 0.60 (95%CI:0.48-0.71). Positive predictive values ranged from 0.68-0.94 and negative predictive values from 0.46-0.86. False-positive rates ranged from 22-50% and false-negative rates from 7-24%.
- Self-OBPM: Only 1 study used SBP/DBP thresholds relevant to current practice and reported a sensitivity of 0.92 and specificity of 0.25. The positive predictive value was 0.59 and the negative predictive value was 0.72. The false-positive rate was 75% and the false-negative rate was 8%.
- Truncated ABPM: One study was found that reported accuracy of a truncated ABPM compared with full 24-hour BPM test, with a sensitivity of 0.94 and specificity of 0.76.
- 13 Fair-to good-quality studies (n=5150) examined the harms of screening and diagnosis of hypertension. Limited evidence suggests that screening is associated with no decreased in QoL or psychological distress, evidence on absenteeism was mixed. ABPM follow-up testing is associated with minor adverse events including temporary sleep disturbance and bruising. Inaccurate diagnoses are also considered harms of screening and confirmation.
This study provides an overview of benefits and harms of screening for hypertension in adults, and lists the accuracy of screening and confirmatory BP measurements. The focus was on the accuracy of tests and the harms of screening, as hypertension screening is standard practice and it is not feasible of ethical to study screening in trial setting.
Major accuracy limitations, such as misdiagnosis, were observed with screening using office-based BP measurements. Therefore, there is a need for research to establish algorithms for optimal screening and confirmation of hypertension in clinical practice.