Validity of mass blood pressure screening in children.

The validity of a mass blood pressure screening program carried out on Dallas high school students who were followed for at least 3 years is reported. Blood pressure results on initial screening in the tenth grade were related to outcome blood pressure status. The frequency of initial blood pressure elevation (systolic and/or diastolic pressure above the 95th percentile) was 10%, whereas the prevalence of sustained elevation in the tenth grade was less than 2%. The initial screening correctly identified 72% of those who had sustained elevations on all three tenth grade examinations (sensitivity), and correctly identified 91% of those who did not have sustained elevations (specificity). However, the predictive value of an initial positive screening result was low, at only 17% (152/900). The high proportion of false-positive results represents a significant cost to any blood pressure screening program, both in economic terms and in its potential for creating anxiety among families with children having only transiently elevated blood pressure. Because the costs are high and the yield from mass screening of children low, case finding of childhood hypertension should remain the responsibility of the physician who sees children in the clinical setting.