Prevalence of Resistant Hypertension With DOT (DOT)

The Prevalence of Pseudo-resistant Hypertension Using the Direct Observed Therapy Test: A Prospective Observational Study

High blood pressure is a risk factor for bad clinical events, such as heart failure, stroke, kidney failure and death. This risk is much higher in those with 'resistant' hypertension, in whom the blood pressure remains high despite more than 3 blood pressure medicines. Current estimates of the proportion of individuals with resistant hypertension may be an overestimate, since some of them are not actually adherent (i.e. not taking the medicines they are prescribed). Methods to detect non-adherence, such as asking the patient, counting pills, and getting records from pharmacy are not fool proof. Direct observed therapy (where patients are administered medicines under observation by a health care personnel) is quite useful to diagnose this, and is the standard of care in the Renal Hypertension Clinic, before more tests and interventions (such as CT scans, renal angiogram) are performed.

In this study, the investigators will measure the proportion of patients with resistant hypertension who are non-adherent based on direct observed therapy, and follow them up to examine the impact of this diagnosis.

Study Overview

• Status: Completed
• Conditions: Hypertension
• Intervention / Treatment: Procedure: Direct Observed Therapy test

Detailed Description

This is a prospective, observational study.

Patients fitting inclusion and exclusion criteria, after informed consent, will undergo the direct observed therapy test in the hypertension unit (this is usual care in the unit, which they will undergo even if they are not part of the study).

The Direct Observation Therapy (DOT) Test includes the following components:

1. Administer and observe ingestion of usual morning antihypertensive medications.
2. Monitor BP every 30 minutes, using 5 readings of an automated oscillometric BP device ( BP-TRU), until plateau affect achieved, defined as 3 consecutive cycles of BP readings declining by less than 10 mmHg per cycle).
3. Registered Nurse (RN) repeats standing BP prior to initiation of 24 hour Ambulatory Blood Pressure Monitoring(ABPM).
4. RN initiates 24 hour ABPM

In addition, participants will undergo an additional 24-hour ABPM test 1 month after the DOT test is undertaken.

• Study Type: Observational
• Enrollment (Actual): 60

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Ottawa, Ontario, Canada, K1H7W9
      • Ottawa Hospital Research Institute

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

The study population is patients with resistant hypertension referred to a tertiary care hypertension clinic.

Description

Inclusion Criteria:

1. Age 18 years or older
2. Confirmed resistant hypertension defined as daytime BP readings above 135/85 mmHg (confirmed by 24-hour ABPM results) using 3 or more BP lowering drugs
3. Adherence to medications confirmed by patient, and by hypertension clinic on basis of pharmacy filling record

Exclusion Criteria:

1. Pregnant patients
2. Inability to provide informed consent

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Direct Observed Therapy test; Patients with resistant hypertension (as defined in the eligibility criteria) will be enrolled. They will all have undergone 24 hour ambulatory blood pressure monitoring (ABPM) before enrollment. As part of the study, the subjects will undergo direct observed therapy testing, followed by another 24 hour ABPM, which will be repeated at 1 month.	Procedure: Direct Observed Therapy test; There is one group only, all of whom will undergo direct observed therapy testing

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of true resistant hypertension	The proportion of patients who continue to have resistant hypertension after administration of direct observed therapy, on the basis of the 24 hour ambulatory testing	1 week

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prevalence of resistant hypertension at 1 month	The proportion of patients who continue to have resistant hypertension at one month, on the basis of the 24 hour ambulatory testing	1 month

Collaborators and Investigators

• Sponsor: Ottawa Hospital Research Institute
• Investigators: Principal Investigator: Marcel Ruzicka, MD PhD, Ottawa Hospital Research Institute

Study record dates

Study Major Dates

• Study Start: September 1, 2015
• Primary Completion (Actual): July 1, 2018
• Study Completion (Actual): September 1, 2018

Study Registration Dates

• First Submitted: July 23, 2015
• First Submitted That Met QC Criteria: July 29, 2015
• First Posted (Estimate): July 31, 2015

Study Record Updates

• Last Update Posted (Actual): March 21, 2019
• Last Update Submitted That Met QC Criteria: March 19, 2019
• Last Verified: March 1, 2019

More Information

Terms related to this study

• Keywords: adherence; hypertension; blood pressure; non-adherence; resistant hypertension
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: 4096