Screening for eligibility in the study of antihypertensive medication in children: Experience from the Ziac Pediatric Hypertension Study

Background: The FDA Modernization Act has resulted in an increase in pediat ric trials of antihypertensive medications. As experience is limited in chi ldren to guide the planning of these studies, we reviewed data from the Zia c Pediatric Hypertension Study to determine patterns of early study termina tion to help future studies. Methods: For inclusion., subjects aged 6 to 17 years were required to have an average systolic blood pressure (SBP) or diastolic blood pressure (DBP) above the 95th percentile at the last of three visits during 2 weeks of sin gle-blind placebo screening. Early study termination was defined as early t ermination for any reason. Screening termination was defined as normalizati on of blood pressure (BP) during the placebo screening phase. Results: Early study termination rate was 27% (38 of 140 subjects). The mos t common reason was screening termination due to normalization of BP, accou nting for 63% of all early study terminations. Among screening termination subjects who completed three screening visits, SBP was higher (P < .001) at visit 1 (129 +/- 8 mm Hg) than at visit 2 (123 +/- 7 mm Hg) or visit 3 (12 1 +/- 8 mm Hg), but did not differ between visits 2 and 3. Screening termin ation occurred in 15% with isolated SBP hypertension, and 21%. with isolate d DBP hypertension. At randomization. 83% had SBP hypertension and 53% had DBP hypertension. Conclusions. These data suggest that SBP hypertension should be part of inc lusion criteria to increase enrollment and reduce the rate of screening ter mination, and that 1-week placebo screening is necessary and sufficient to minimize inclusion of transiently hypertensive subjects. (C) 2001 American Journal of Hypertension, Ltd.