-
Views
-
Cite
Cite
Thomas G. Wells, Zhongxin Zhang, Beth A. Soffer, Wayne C. Shaw, Pamela L. Herrera, Shahnaz Shahinfar, P-241: Antihypertensive trial design in children: Blood pressure variability among the hypertensive children enrolled in the Enalapril Pediatric Study, American Journal of Hypertension, Volume 14, Issue S1, April 2001, Page 109A, https://doi.org/10.1016/S0895-7061(01)01431-5
Close - Share Icon Share
Abstract
The data from the Enalapril Pediatric Hypertension Study were examined to compare the estimated standard deviation (SD) for sitting systolic (SiSBP) and diastolic (SiDBP) blood pressures (BP) of the hypertensive children included in the study with estimates from the general pediatric population. The best available estimate of (BP) variability in children was published in the Second Task Force Report (Pediatrics, 1987, 79:1-25). For children aged 6-16 years, the SD for SiSBP ranged from 10.0 to 12.9 mmHg (based on single clinic BP measurement). In children aged 13-16 years, the SD for SiDBP using the 5th Korotkoff sound (K5) ranged from 10.5 to 12.7 mmHg (SBPM). Values for K5 were not published for children ≤ 12 years of age. In Period 1 of the enalapril study, patients were randomized to 1 of 3 enalapril treatments q.d. for 14 days: 0.625/1.25 mg, 2.5/5 mg, or 20/40 mg (based on weight). In Period 2, patients either continued their current study regimen or were switched to placebo for up to 2 weeks or when their BP returned to baseline, whichever came first. For Period 1, the power calculation was based on a desired difference (δ) of 5 mmHg in the mean trough SiDBP between high- and low-dose groups. For Period 2, the desired difference (δ) in the mean trough SiDBP between active treatment and placebo groups was also set at 5 mmHg. All BP readings were the mean of 3 measurements. Planned and actual values for each period are shown: (See Table)
| Period 1 . | Planned SiDBP . | Actual SiDBP . | Actual SiSBP . |
|---|---|---|---|
| Sample Size | 100 | 109 | 109 |
| δ(mmHg) | 5 | 7.75 | 5.89 |
| SD (mmHg) | 8 | 8.35 | 10.65 |
| Period 2 | Planned SiDBP | Actual SiDBP | Actual SiSBP |
| Sample Size | 100 | 101 | 101 |
| δ(mmHg) | 5 | 6.09 | 8.35 |
| SD (mmHg) | 8 | 9.46 | 11.07 |
| Period 1 . | Planned SiDBP . | Actual SiDBP . | Actual SiSBP . |
|---|---|---|---|
| Sample Size | 100 | 109 | 109 |
| δ(mmHg) | 5 | 7.75 | 5.89 |
| SD (mmHg) | 8 | 8.35 | 10.65 |
| Period 2 | Planned SiDBP | Actual SiDBP | Actual SiSBP |
| Sample Size | 100 | 101 | 101 |
| δ(mmHg) | 5 | 6.09 | 8.35 |
| SD (mmHg) | 8 | 9.46 | 11.07 |
| Period 1 . | Planned SiDBP . | Actual SiDBP . | Actual SiSBP . |
|---|---|---|---|
| Sample Size | 100 | 109 | 109 |
| δ(mmHg) | 5 | 7.75 | 5.89 |
| SD (mmHg) | 8 | 8.35 | 10.65 |
| Period 2 | Planned SiDBP | Actual SiDBP | Actual SiSBP |
| Sample Size | 100 | 101 | 101 |
| δ(mmHg) | 5 | 6.09 | 8.35 |
| SD (mmHg) | 8 | 9.46 | 11.07 |
| Period 1 . | Planned SiDBP . | Actual SiDBP . | Actual SiSBP . |
|---|---|---|---|
| Sample Size | 100 | 109 | 109 |
| δ(mmHg) | 5 | 7.75 | 5.89 |
| SD (mmHg) | 8 | 8.35 | 10.65 |
| Period 2 | Planned SiDBP | Actual SiDBP | Actual SiSBP |
| Sample Size | 100 | 101 | 101 |
| δ(mmHg) | 5 | 6.09 | 8.35 |
| SD (mmHg) | 8 | 9.46 | 11.07 |
Actual SDs were obtained from pooled SDs for each treatment arm in both Periods. The SD for SiDBP in hypertensive children, under the criteria, was less than expected from previously published results. SD results for SiSBP were similar to previously published results in a non-selected population. Accordingly, given similar inclusion and exclusion criteria, the power analysis for studies using SiDBP as the primary outcome measure may employ slightly lower values for SD than previously published in the literature when using the mean of 3 BP measurements.
