The challenge of correctly diagnosing hypertension in adults

Screening for high blood pressure in adults can be straightforward or quite complex. The U.S. Preventive Services Task Force (USPSTF) recently reaffirmed its longstanding recommendation to screen for hypertension with office blood pressure measurement but advises confirming the diagnosis with measurements outside of the clinical setting. The diagnostic standard for out-of-office measurement is 24-hour ambulatory blood pressure monitoring (ABPM), but ABPM is often unavailable, not covered by insurance, or inconvenient for patients.

A more accessible alternative, reviewed by Dr. Jeffrey Weinfeld and colleagues in the September issue of AFP, is home blood pressure monitoring (HBPM). In addition to confirming a hypertension diagnosis, HBPM can be used to identify white coat hypertension (elevated readings in the office but normal readings at home) and masked hypertension (elevated readings at home but normal readings in the office). Patients can purchase a clinically validated blood pressure monitor for $37 to $100 without insurance, and this expense may be reimbursed from a health care flexible spending account. The downside of HBPM is that patients sometimes forget to check their blood pressures at home or forget to record and bring in the readings. 

What is the role of automated oscillometric office blood pressure (AOBP) devices such as those used in the Systolic Blood Pressure Intervention Trial (SPRINT)? A systematic review and meta-analysis previously summarized in AFP found that AOBP systolic measurements were on average 14.5 mm Hg lower than manual blood pressures in patients with hypertension and better aligned with values obtained with ABPM. In a Letter to the Editor in the August issue, Dr. Lenard Lesser argued that the USPSTF "missed an opportunity to promote AOBP measurements as an easier-to-implement alternative to ambulatory blood pressure monitoring." Dr. Lesser pointed out that the only randomized trial of hypertension screening cited by the USPSTF that reported improvements in clinically meaningful outcomes actually used AOBP.

In the latest entry in JAMA's Rational Clinical Examination series, Dr. Anthony Viera and colleagues systematically reviewed studies that addressed the question, "Does This Adult Patient Have Hypertension?" Comparing AOBP with HBPM, they found that 

The thresholds for defining hypertension and the prevalence of hypertension were similar in office BP measurement and home BP measurement studies, and the estimated predictive values of office oscillometric BP measures and HBPM were numerically nearly identical. ... The combination of results from office BP measurement and HBPM has better diagnostic accuracy than the independent results alone, and when concordant, is likely sufficient for diagnosis. However, 24-hour ABPM should be considered when results are discordant, especially for patients with a higher pretest probability of hypertension.