We conducted this systematic review to support the U.S. Preventive Services Task Force (USPSTF) in updating its recommendation on screening for hypertension in adults. This systematic review addresses the benefits and harms of screening for hypertension in adults, including the accuracy of initial office-based screening measurements during a single encounter and confirmatory blood pressure measurements using various modalities in those who initially screen positive.
We performed a search of MEDLINE, PubMed (publisher-supplied records only), the Cochrane Collaboration Registry of Controlled Trials, and the Cumulative Index of Nursing and Allied Health for relevant English-language studies published between February 2014, and August 2019. Additionally, we re-evaluated all studies included in the 2014 USPSTF review. We supplemented searches by examining bibliographies from retrieved articles and consulting outside experts. We searched clinical trial registries for ongoing and/or unpublished trials. We conducted ongoing surveillance for relevant literature through March 26, 2021.
Two investigators independently reviewed 21,741 abstracts and 544 full-text articles against a set of inclusion and quality criteria. Resolution of disagreements was achieved through discussion with a third reviewer. We included the following study designs: randomized controlled trials (RCTs) and clinical controlled trials (CCTs) for effectiveness of screening (KQ1); test accuracy studies for accuracy of initial office-based blood pressure screening (KQ2) and subsequent confirmatory blood pressure measurements (KQ3) using an ambulatory blood pressure measurement (ABPM) reference standard; and RCTs, CCTs, and cohort and cross-sectional studies for screening and confirmation harms (KQ4).
One investigator abstracted data into evidence tables and a second investigator checked accuracy. We qualitatively synthesized data separately for each key question. We meta-analyzed study results for Key Questions 2 and 3. Our quantitative analyses utilized a bivariate model for sensitivity and specificity outcomes. We used visual inspection of forest plots arranged by various study, population, and test characteristics to explore heterogeneity.
For KQ1, one community-based cluster RCT (N=140,642) of a multicomponent CVD health promotion program that included hypertension screening as the primary intervention for older adults reported a 9 percent relative reduction in composite CVD-related hospital admissions (rate ratio 0.91 [95% CI, 0.86 to 0.97]). For KQ2, meta-analysis of 15 studies (N=11,309) of office-based blood pressure measurement (OBPM) for screening at a single visit demonstrated a pooled sensitivity of 0.54 (95% CI, 0.37 to 0.70) and a pooled specificity of 0.90 (95% CI, 0.84 to 0.95) with considerable clinical and statistical heterogeneity. For KQ3, 18 studies (N=57,128) of various confirmatory blood pressure measurement modalities reported data that allowed accuracy calculations; these studies used confirmation modalities of: OBPM, home blood pressure measurement (HBPM), self-OBPM (measurement performed by a patient in the office setting), and truncated ABPM. Meta-analysis of eight OBPM confirmation studies (N=53,183) showed a pooled sensitivity of 0.80 (95% CI, 0.68 to 0.88) and a pooled specificity of 0.55 (95% CI, 0.42 to 0.66) with considerable clinical and statistical heterogeneity. Meta-analysis of four HBPM confirmation studies (N=1,001) showed a pooled sensitivity of 0.84 (95% CI, 0.76 to 0.90) and a pooled specificity of 0.60 (95% CI, 0.48 to 0.71) with considerable statistical heterogeneity. Two studies of self-OBPM (N=698) and one study of truncated ABPM (N=263) provided a limited evidence base for determination of accuracy for these modalities. There was limited information about the accuracy of protocol variations, precluding conclusions about the optimal protocol characteristics for screening and confirmatory blood pressure measurement in the included studies. For KQ4, 13 studies (N=5,150) suggest that screening is associated with no decrements in quality of life or psychological distress and scant evidence on screening’s effect on absenteeism is mixed. ABPM followup testing is associated with minor adverse events including temporary sleep disturbance and bruising.
The literature identified for blood pressure screening and confirmation accuracy represented a heterogeneous group of studies resulting in inconsistent and imprecise accuracy estimates. The included protocol characteristics for screening and confirmatory blood pressure measurements likely represent “research quality” measures not followed in current practice.
Blood pressure screening at a single visit has a low sensitivity and adequate specificity for detection of hypertension, leading to a substantial number of potentially missed cases. Confirmatory office or home blood pressure measurement applied to a population with a previously elevated blood pressure has adequate sensitivity and low specificity suggesting that these modalities may not be appropriate replacements for ABPM for diagnostic confirmation. Scant literature is available to inform best practices in blood pressure measurement to optimize test accuracy. Limited available evidence on the direct harms of screening and confirmatory blood pressure measurements suggest that the harms are minimal, and the most notable harm of blood pressure screening is likely misdiagnosis with ensuant under or over-treatment. Future research is needed to identify optimal blood pressure measurement protocols and confirmation algorithms—including blood pressure threshold values—to inform clinical practice.
