ABC | Volume 114, Nº3, March 2020

Original Article Arantes et al. Added salt and blood pressure Arq Bras Cardiol. 2020; 114(3):554-561 Therefore, this study evaluated the effect of reducing the intake of added salt on central and peripheral BP in normotensive, prehypertensive and hypertensive individuals after 13 weeks of follow-up. Methods This is a substudy of the phase II, single-blinded, controlled clinical trial with different amounts of added salt in individuals grouped by BP levels. For the initial sample, a total of 1,000 workers were recruited at a Brazilian public university. A questionnaire on dietary habits was administered, and anthropometric and casual BP measurements were performed. Of the subjects recruited, 678 agreed to participate (Figure 1). The study was approved by the ethics committee (CAEE:  00790712.3.0000 .5078) and all participants signed an informed consent form. The study population was a convenience sample and was composed of men and women aged between 20 and 60 years. All participants had at least four main meals (lunch and/or dinner) a week at home. Individuals with casual BP ≥ 160/100 mmHg, diabetes, history of chronic disease and hypertension taking two or more antihypertensive were excluded. Participation of the study consisted of five visits with an interval of 30 ± 7 days between them. The first visit was divided into two parts, Visit 1A (V1A) and Visit 1B (V1B). In all visits, measurements of casual BP, CBP, ABPM and BMI were performed, and request for urinalysis, and 24-hour urine creatinine, sodium and potassium was made. In V1A, in addition to these procedures, participants also signed the informed consent form, were evaluated for eligibility criteria and a request for serum creatinine was made. In V1B, participants were grouped according to mean casual BP, in normotensive (NG) (BP < 130/85 mmHg), prehypertensive (PHG) (BP ≥ 130 < 140/≥85 < 90 mmHg) and stage 1 hypertensive (HG) (BP ≥ 140 and < 160/≥ 90 and < 100 mmHg) not using antihypertensive medication. 1 For casual BP, three measurements were taken with a minimum interval of one minute between them. When a difference greater than 4 mmHg was found between the measurements, further measures were taken until the differences between them were smaller. Both casual BP and ABPM were measured using a semiautomated device (OMRON, model HEM-711ACINT), with a cuff size according to the armcircumference. BPwas measured in the sitting position after a resting period of five minutes, in a calm environment in the arm with the highest BP value. 1 ABPM was performed according to the II Brazilian Guidelines for Ambulatory Blood Pressure Monitoring. 17 In each visit, the ABPM device was given to each participant, who was instructed to obtain BP measures following specific protocol, to write down the values in a proper document and to return the device at the next visit. Figure 01 – Flowchart of the phase II clinical trial. Phase I 1000 participants Clinical trial Phase II 678 Selected 111 Eligible 50 Normotensive 15 Normotensive 18 Prehypertensive 22 Hypertensive 2 withdrew consent 19 withdrew consent 20 Borderline 41 Hypertensive Withdrawal of consent Lack of eligibility Wrong contacts 567 Excluded 33 withdrew consent 2 lost to follow-up 555