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

Study Overview
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Brief Summary
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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.

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

Conditions
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Hypertension

Intervention / Treatment
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* Other: Favor one of two thiazides for new prescriptions & attempt target dose


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: VA prescribers of thiazides for hypertension Exclusion Criteria: at non-participating VA sites
Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Favor Chlorthalidone<br>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<br>* 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.<br>|
| Active Comparator: Favor Hydrochlorothiazide<br>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<br>* 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.<br>|

What is the study measuring?
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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 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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prescribing patterns, thiazide, chlorthalidone, hydrochlorothiazide, target dose, cluster randomized trial