Effect of Salt Restriction on Renin Activation

Investigation of Salt Restriction Effect on Renin Activation

The present prospective, randomized, crossover study is designed to investigate the effect of salt consumption on blood pressure in hypertensive subjects.

Secondary objectives of the study are to evaluate the effect of salt consumption on blood pressure among the subjects who are hypertensive and obese and normal according to body mass index and to evaluate the effect of salt consumption on renin activity in hypertensive subjects.

Study Overview

• Status: Completed
• Conditions: Hypertension
• Intervention / Treatment: Behavioral: Lowering salt in diet

Detailed Description

The present study is carried out with the subjects who are chosen among the nursing home residents in İzmir. The subjects were randomized to 2 groups and while one of these groups had low salt diet (50mmol), the other group had normal salt diet (250mmol) for 3 weeks. Subjects had normal salt diet in their daily routine life for the following 2 weeks. According to crossover nature of the study, the group that had normal salt diet at the first 3 weeks of study had low salt diet at the last 3 weeks of the study. The other group that had low salt diet had the normal salt diet at the last 3 week of the study.

At the beginning of the study, information such as demographic, family story, medical story, diet habits, concomitant medication and physical measurements (height, weight and waist circumference) were received from the subjects.

24 hour blood pressure of the subjects is measured for four times, before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet. The subjects were asked for collecting 24-h urine in the same days of blood pressure measurement. Sodium, potassium, urea, creatinin and microalbumin measurements were measured in the collected urine. Blood samples were collected for three times, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet. Plasma renin activity and aldosterone levels were measured in the blood samples collected. Aldosterone level was measured in the 24-hour urine in mentioned days.

• Study Type: Interventional
• Enrollment (Actual): 28
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 50 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Subjects who are 50 years and older
• Subjects whose systolic blood pressure is ≥ 140 mmHg
• Subjects whose diastolic blood pressure is ≥ 90 mmHg
• Subjects who is normal weighted defined as body mass index < 25 or who is obese defined as body mass index > 30
• Subjects who have intellectual capacity to adapt diets and 24 hour urine collection
• Informed about the study and consented to include the study

Exclusion Criteria:

• Known heart failure
• Known renal failure
• Known chronic liver disease
• Antihypertensive drug use
• nonsteroidal anti inflammatory (NSAI) drug use

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
No Intervention: Normal salt diet; The group had normal salt diet (250mmol)for three weeks. Subjects had normal salt diet in their daily routine life for the following 2 weeks.According to crossover nature of the study, the group had low salt diet (50mmol) at the last 3 weeks of the study.
Experimental: Low salt diet; The group had low salt diet (50mmol)for three weeks. Subjects had normal salt diet in their daily routine life for the following 2 weeks.According to crossover nature of the study, the group had normal salt diet at the last 3 weeks of the study.	Behavioral: Lowering salt in diet; Low salt diet (50mmol)for three weeks.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change from baseline in 24-hour ambulatory blood pressure at 3 weeks	24-hour ambulatory blood pressure was measured before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	3 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in sodium levels in urine samples.	Sodium was measured in 24-hour collected urine samples before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	3 weeks
Change in plasma renin activity	Plasma renin activity level was measured in the blood samples collected, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	For 3 times in 8 weeks
Change in aldosterone level in blood samples	Aldosterone levels was measured in the blood samples collected , at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	For 3 times in 8 weeks
Change in potassium levels in urine samples.	Potassium was measured in 24-hour collected urine samples before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	3 weeks
Change in urea level in urine samples	Urea was measured in 24-hour collected urine samples before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet	3 weeks
Change in creatinin level in urine samples	Creatinin was measured in 24-hour collected urine samples before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	3 weeks
Change in microalbumin level in urine samples	Microalbumin was measured in 24-hour collected urine samples before the beginning of diet specific to their groups, at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet	3 weeks
Change in aldosterone level in urine samples	Aldosterone levels was measured in in the 24-hour urine samples collected , at the end of the 3-week diet, before the beginning of the second diet and at the end of their second diet.	For 3 times in 8 weeks

Collaborators and Investigators

• Sponsor: Turkish Society of Hypertension and Renal Diseases
• Investigators: Principal Investigator: Mustafa Arici, Prof., Hacettepe University Faculty of Medicine Department of Nephrology

Study record dates

Study Major Dates

• Study Start: March 1, 2011
• Primary Completion (Actual): July 1, 2011
• Study Completion (Actual): July 1, 2011

Study Registration Dates

• First Submitted: June 13, 2012
• First Submitted That Met QC Criteria: June 22, 2012
• First Posted (Estimate): June 26, 2012

Study Record Updates

• Last Update Posted (Estimate): June 26, 2012
• Last Update Submitted That Met QC Criteria: June 22, 2012
• Last Verified: August 1, 2011

More Information

Terms related to this study

• Keywords: Hypertension,plasma renin activity,salt consumption
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: HT-Salt