Tolerance to Target Doses of Thiazides in Actual Practice: A Feasibility Study

This is a pilot study of a method to compare common, FDA-approved drugs in a clinic. Instead of putting single patients into one of two drug groups, the investigators will assign the doctors who prescribe these drugs for high blood pressure into two groups. One group of doctors has agreed to prescribe mostly ("favor") one drug, chlorthalidone, if that drug would be a good choice for a patient. The other group has agreed to prescribe mostly hydrochlorothiazide. For both groups, they will try to use the doses that were shown to be protective in other trials. If the doctors mostly prescribe the drug they agreed to favor, the investigators will be able to compare outcomes, like heart attacks, in the two groups.

Study Overview

• Status: Completed
• Conditions: Hypertension
• Intervention / Treatment: Other: Favor one of two thiazides for new prescriptions & attempt target dose

• Study Type: Interventional
• Enrollment (Actual): 20
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Illinois
    • Hines, Illinois, United States, 60141
      • Edward Hines, Jr. VA Hospital
  • North Carolina
    • Asheville, North Carolina, United States, 28805
      • Charles George VAMC
  • Pennsylvania
    • Wilkes-Barre, Pennsylvania, United States, 18711
      • Wilkes-Barre VA Medical Center
  • South Carolina
    • Columbia, South Carolina, United States, 29209
      • WJB Dorn VA Medical Center
    • Orangeburg, South Carolina, United States, 29118
      • WJB Dorn VAMC/Columbia Orangeburg VA Outpatient Clinic

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult; Older Adult
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• VA prescribers of thiazides for hypertension

Exclusion Criteria:

• at non-participating VA sites

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Health Services Research
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Favor Chlorthalidone; Providers randomized to Favor Chlorthalidone will have agreed to prescribe chlorthalidone for patients who are to be newly prescribed a thiazide for hypertension, whether the thiazide is 1st line or add-on therapy. This cluster designation applies only for patients for whom there is equipoise; providers are expected to deviate if medically indicated for individual patients	Other: Favor one of two thiazides for new prescriptions & attempt target dose; Providers will be randomized to either Favor Chlorthalidone or Favor Hydrochlorothiazide for patients who are to be newly prescribed a thiazide for hypertension, whether the thiazide is 1st line or add-on therapy. Providers will have agreed to adhere to their assignment for patients for whom there is equipoise, but they are free to deviate if medically indicated for individual patients. There is no requirement to maintain the initial thiazide therapy; it is expected that the regimen may require adjustment over time. The cluster assignment is simply to favor a particular thiazide on initiation of thiazide therapy and attempt to reach the target dose.
Active Comparator: Favor Hydrochlorothiazide; Providers randomized to Favor Hydrochlorothiazide will have agreed to prescribe hydrochlorothiazide for patients who are to be newly prescribed a thiazide for hypertension, whether the thiazide is 1st line or add-on therapy. This cluster designation applies only for patients for whom there is equipoise; providers are expected to deviate if medically indicated for individual patients	Other: Favor one of two thiazides for new prescriptions & attempt target dose; Providers will be randomized to either Favor Chlorthalidone or Favor Hydrochlorothiazide for patients who are to be newly prescribed a thiazide for hypertension, whether the thiazide is 1st line or add-on therapy. Providers will have agreed to adhere to their assignment for patients for whom there is equipoise, but they are free to deviate if medically indicated for individual patients. There is no requirement to maintain the initial thiazide therapy; it is expected that the regimen may require adjustment over time. The cluster assignment is simply to favor a particular thiazide on initiation of thiazide therapy and attempt to reach the target dose.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Prescription Rates	rates of provider prescribing of the Cluster Designated drug	nine months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Factors Associated With Prescribing Patterns	factors (barriers and facilitators) associated with prescribing according to the Cluster Designation	nine months

Collaborators and Investigators

• Sponsor: VA Pharmacy Benefits Management Strategic Healthcare Group
• Investigators: Principal Investigator: Madeline McCarren, PhD, MPH, VA Pharmacy Benefits Management

Study record dates

Study Major Dates

• Study Start: September 1, 2011
• Primary Completion (Actual): October 1, 2013
• Study Completion (Actual): February 1, 2014

Study Registration Dates

• First Submitted: November 4, 2010
• First Submitted That Met QC Criteria: November 4, 2010
• First Posted (Estimate): November 5, 2010

Study Record Updates

• Last Update Posted (Estimate): November 25, 2014
• Last Update Submitted That Met QC Criteria: November 17, 2014
• Last Verified: November 1, 2014

More Information

Terms related to this study

• Keywords: chlorthalidone; hydrochlorothiazide; cluster randomized trial; thiazide; prescribing patterns; target dose
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: VMS156