UT Health Study: Treating Children With Hypertension With N of 1 Trials

UT Health Study Treating Children With Hypertension With N of 1 Trials

The University of Texas Health Science Center at Houston recently completed a pioneering study utilizing a series of personalized trials to identified preferred therapy for kids with high blood pressure.

Hypertension in Children

About 4% or 1.2 million children are thought to face hypertension, although it is believed to be increasing due to the obesity epidemic.

The Study

The UT Health team designed a series of N of 1 trials—single-patient, randomized trials in which a patient tries different medications and is monitored to see which ones are the most effective with the fewest side effects. They worked to identify the preferred therapy for the patient from among three major classes of commonly used blood pressure drugs.

The N of 1 trial commenced with the verification of the need for ongoing pharmacologic care—some cases could be controlled without drugs by rather introducing lifestyle modification, such as diet or exercise.

A novel study in a couple different ways: 1) it was the first known study to use N of 1 methodology in this specific population (e.g. children with hypertension) and 2) it was the first to use repeated 24-hour ambulatory blood pressure monitors to record readings periodically throughout the day rather than measuring patients just at the physician’s office.

Throughout the series, 32 patients at UT Physicians clinics and Harris Health Lyndon B. Johnson Hospital were administered the three different drugs in a random order for two-week durations. At the end of each two-week period, patients wore the 24-hour ambulatory blood pressure monitor as well as completed a side-effect questionnaire.

The study design built in the following conclusion: after all three drugs were tried and the best drugs repeated—the physician, the patient, and the family decided together on which medication would be prescribed long-term for the patient. The study was published in Pediatrics.


No single medication was preferred for a majority of the patients. A considerable variation in blood pressure was observed in this study. The best performing drug decreased blood pressure by about 12 units of pressure more than patient’s worst-performing treatment. 23% of the patients did not need to be on medication at all.

Principal Investigator Joyce Samuel noted, “Our finding that there was no single drug chosen for the great majority of patients, and that the difference between the drugs that worked the best and worst was so significant, prompted us to consider whether n-of-1 trials should be used in routine clinical practice because often there’s not just one drug that works for everyone. In the era of personalized medicine, this is a big step towards individualizing how we treat patients. We need to find better ways of choosing which treatment we are going to use and tailoring our therapy for each patient.”

What is an N of 1 Trial?

A clinical trial in which a single patient is the entire trial, a single case study; a trial which in which a random allocation can be used to determine the order in which an experimental and control intervention are given to a patient is an N of 1 randomized controlled trial. The order of experimental and control interventions can also be fixed by the investigator.

This class of trial was formed to enable investigators to pursue experimental progress without the overwhelming work of designing and planning a group comparison study. N-of-1 trials can be effective in confirming causality.

In 2011, Scripps’ researchers published The n-of-1 clinical trial: the ultimate strategy for individualizing medicine? 

Lead Research/Investigator

Joyce Samuel, MD, MS 

Jon Tyson, MD, MPH 

Joshua Samuels, MD, MPH