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Salt Loading and Thiazide Intervention Study (SALTI)

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ClinicalTrials.gov Identifier: NCT00896389
Recruitment Status : Completed
First Posted : May 11, 2009
Results First Posted : May 31, 2018
Last Update Posted : May 31, 2018
Sponsor:
Collaborator:
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Information provided by (Responsible Party):
Yen-Pei Christy Chang, University of Maryland

Study Type: Interventional
Study Design: Intervention Model: Single Group Assignment;   Masking: None (Open Label);   Primary Purpose: Treatment
Condition: Hypertension
Interventions: Procedure: Salt loading
Drug: Hydrochlorothiazide (HCTZ)

  Participant Flow

Recruitment Details
Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
No text entered.

Pre-Assignment Details
Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
No text entered.

Reporting Groups
  Description
Salt-loading and Thiazide Diuretics (HCTZ) Salt loading: 2 liters (L) of 0.9% sodium chloride (NaCl). HCTZ:12.5 or 25 mg of HCTZ for 1 week

Participant Flow for 3 periods

Period 1:   Salt Loading
    Salt-loading and Thiazide Diuretics (HCTZ)
STARTED   124 
COMPLETED   124 
NOT COMPLETED   0 

Period 2:   HCTZ Low Dose
    Salt-loading and Thiazide Diuretics (HCTZ)
STARTED   28 [1] 
COMPLETED   28 
NOT COMPLETED   0 
[1] Only subjects with SBP > 120 mmHg and agreeable to the HCTZ protocol continued to the next period.

Period 3:   HCTZ High Dose
    Salt-loading and Thiazide Diuretics (HCTZ)
STARTED [1]   25 
COMPLETED   25 
NOT COMPLETED   0 
[1] Of the 28 subjects that started HCTZ intervention, 3 terminated the study without completing.



  Baseline Characteristics

Population Description
Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
No text entered.

Reporting Groups
  Description
Salt-loading and Thiazide Diuretic (HCTZ)

Salt loading: Subjects will arrive at the Amish Research Clinics after overnight fasting. After taking height, weight, BP, and body temperature, subjects will receive 2 L of 0.9% NaCl (sodium chloride) saline over 4 hours while their blood pressure is monitored every 15 minutes. Blood pressure will be taken every 15 minutes during this procedure. Blood and urine samples will be collected from all subjects pre- and post-infusion.

Hydrochlorothiazide (HCTZ): After overnight fasting and having their height, weight, and BP measured, subjects are given 12.5 mg HCTZ tablets and instructed to take 1 tablet daily for one week. Ambulatory blood pressure, blood and urine will be collected on both day 1 and day 8. After a wash-out period, the subjects will repeat the HCTZ intervention, taking 25 mg HCTZ instead.


Baseline Measures
   Salt-loading and Thiazide Diuretic (HCTZ) 
Overall Participants Analyzed 
[Units: Participants]
 124 
Age [1] 
[Units: Years]
Mean (Standard Deviation)
 
Saline infusion only   
Participants Analyzed   124 
Saline infusion only   50  (7) 
saline infusion and HCTZ   
Participants Analyzed   28 
saline infusion and HCTZ   53  (9) 
[1] Only subjects whose baseline blood pressure is high enough (SBP>120 or DBP>80 mmHg) and willing to undergo the multi-week intervention were enrolled into the HCTZ part of the study.
Sex: Female, Male 
[Units: Participants]
Count of Participants
 
Participants Analyzed   124 
Female      71  57.3% 
Male      53  42.7% 
Systolic blood pressure [1] 
[Units: mmHg]
Mean (Standard Deviation)
 
Salt loading   
Participants Analyzed   124 
Salt loading   114  (11) 
HCTZ   
Participants Analyzed   28 
HCTZ   126  (10) 
[1] Only subjects whose baseline blood pressure is high enough (SBP>120 or DBP>80 mmHg) and willing to undergo the multi-week intervention were enrolled into the HCTZ part of the study.
Diastolic blood pressure [1] 
[Units: mmHg]
Mean (Standard Deviation)
 
Salt Loading   
Participants Analyzed   124 
Salt Loading   71  (7) 
HCTZ   
Participants Analyzed   28 
HCTZ   80  (7) 
[1] Only subjects whose baseline blood pressure is high enough (SBP>120 or DBP>80 mmHg) and willing to undergo the multi-week intervention were enrolled into the HCTZ part of the study.
BMI 
[Units: Kg/m2]
Mean (Standard Deviation)
 
Participants Analyzed   124 
   26.1  (2.8) 
creatinine 
[Units: mg/dL]
Mean (Standard Deviation)
 
Participants Analyzed   124 
   0.74  (0.12) 


  Outcome Measures

1.  Primary:   Blood Pressure Change During Salt Loading   [ Time Frame: Every 15 minutes for 4 hours ]

2.  Primary:   Blood Pressure Change After 7 Days of Low Dose (12.5 mg) of HCTZ   [ Time Frame: 24-hr Ambulatory blood pressure were measured every hour on day 0 and day 8 ]

3.  Primary:   Blood Pressure Change After 7 Days of High Dose (25 mg) of HCTZ   [ Time Frame: 24-hr Ambulatory blood pressure were measured every hour on day 0 and day 8 ]

4.  Primary:   Fasting Glucose Change After 7 Days of Low Dose (12.5 mg) of HCTZ   [ Time Frame: Fasting glucose was measured on day 0 and day 8 ]

5.  Primary:   Fasting Glucose Change After 7 Days of High Dose (25mg) of HCTZ   [ Time Frame: Fasting glucose was measured on day 0 and day 8 ]

6.  Secondary:   Change in Plasma Aldosterone Level Due to Salt-loading   [ Time Frame: Aldosterone was measured from blood collected pre and post salt loading ]

7.  Secondary:   Change in Plasma Renin Activity Due to Salt-loading   [ Time Frame: Renin was measured from blood collected pre and post salt loading ]

8.  Secondary:   Change in Plasma Sodium/Potassium Level Due to Salt-loading   [ Time Frame: Plasma sodium and potassium measured from blood collected pre and post salt loading ]

9.  Secondary:   Change in Plasma Sodium/Potassium Level During Low Dose of HCTZ   [ Time Frame: Plasma sodium and potassium measured from blood collected pre and post salt loading ]

10.  Secondary:   Change in Plasma Sodium/Potassium Level During High Dose of HCTZ   [ Time Frame: Plasma sodium and potassium measured from blood collected pre and post salt loading ]


  Serious Adverse Events


  Other Adverse Events


  Limitations and Caveats

Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
No text entered.


  More Information

Certain Agreements:  
Principal Investigators are NOT employed by the organization sponsoring the study.
There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.


Results Point of Contact:  
Name/Title: Dr. Yen Pei Christy Chang
Organization: University of Maryland, Baltimore
phone: 410-706-6737
e-mail: cchang@som.umaryland.edu


Publications:

Responsible Party: Yen-Pei Christy Chang, University of Maryland
ClinicalTrials.gov Identifier: NCT00896389     History of Changes
Other Study ID Numbers: HP-00040712
R21DK084566 ( U.S. NIH Grant/Contract )
First Submitted: May 7, 2009
First Posted: May 11, 2009
Results First Submitted: May 21, 2018
Results First Posted: May 31, 2018
Last Update Posted: May 31, 2018