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 single-blind placebo screening. Early study termination was defined as early termination for any reason. Screening termination was defined as normalization of blood pressure (BP) during the placebo screening phase.
Results: Early study termination rate was 27 % (38 of 140 subjects). The most common reason was screening termination due to normalization of BP, accounting 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 (121 ± 8 mm Hg), but did not differ between visits 2 and 3. Screening termination occurred in 15 % with isolated SBP hypertension, and 21 % with isolated DBP hypertension. At randomization, 83 % had SBP hypertension and 53 % had DBP hypertension.
Conclusions: These data suggest that SBP hypertension should be part of inclusion criteria to increase enrollment and reduce the rate of screening termination, and that 1-week placebo screening is necessary and sufficient to minimize inclusion of transiently hypertensive subjects.