- Kenny Lin, MD, MPH
Several of my hypertensive patients always have significantly higher blood pressures at the office than at home. Even after verifying the appropriate size cuff, and re-measuring blood pressure several minutes into the visit, the numbers don't change. Since treating these patients based solely on office blood pressures risks overtreatment (prescribing too high a dose or too many drugs), I encourage them to keep logs of their home blood pressures for us to review at each followup visit. However, as outlined in this home blood pressure measurement protocol from a previous AFP article, interpreting the results can be complex and challenging to carry out in a time-constrained primary care visit.
In a recent study published in the Annals of Family Medicine, a team of Australian researchers monitored 286 patients with uncomplicated hypertension to determine a more efficient method for interpreting home blood pressure measurements. They found that participants with 3 or more of their last 10 home systolic blood pressures greater than or equal to 135 mm Hg were the most likely to have elevated 24-hour ambulatory blood pressures and signs of end organ disease on echocardiography. This correlation held even if patients did not follow the recommended home monitoring protocol. The researchers concluded that using this "3 in 10" threshold may be a more practical way to assess blood pressure control with home measurements.
Although this study only included patients with established hypertension diagnoses, the U.S. Preventive Services Task Force has emphasized the importance of obtaining blood pressure measurements outside of the clinical setting in its 2015 recommendation statement on screening for high blood pressure in adults. According to this Figure, 6 studies found that home blood pressure monitoring confirmed elevated office blood pressure readings only 45 to 84 percent of the time.
In light of recent trial findings that setting lower blood pressure goals may improve outcomes in patients at high risk for cardiovascular events, it will be even more critical to verify office blood pressure measurements with measurements outside of the office to maximize treatment benefits and minimize adverse effects.