Difference in 24‐hour urine sodium excretion between controlled and uncontrolled patients on antihypertensive drug treatment

Abstract

The objective of this study was to evaluate the association between sodium intake and blood pressure (BP) control in hypertensive patients taking antihypertensive medications by using 24‐hour urine collection and 24‐hour ambulatory BP. This is a cross‐sectional community‐based study and conducted in 2011 and 2012. A total of 1128 participants were recruited from five cities in Korea. Among them, 740 participants who had complete 24‐hour urine collection and valid 24‐hour ambulatory BP data were included in this study. Participants were divided into four groups: normotensives (NT, n = 441), untreated hypertensive patients (UTHT, n = 174), controlled hypertensive patients (CHT, n = 62), and uncontrolled hypertensive patients (UCHT, n = 63). UCHT and CHT groups showed higher mean age than NT and UTHT groups. UCHT and UTHT groups showed higher 24‐hour systolic BP (SBP) and diastolic BP (DBP) than NT and CHT groups. UCHT group had the highest level of 24‐hour urine sodium. Multivariate analysis adjusted with age, gender, body mass index, estimated glomerular filtration rate, and use of diuretics showed higher level of 24‐hour urine sodium in UCHT group than that in CHT group. Multivariate logistic regression analysis revealed independent association of the amount of 24‐hour urine sodium with uncontrolled BP in hypertensive patients on antihypertensive drug treatment. Higher level of 24‐hour urine sodium excretion in uncontrolled hypertensive patients suggests that excessive sodium intake could be associated with blunted BP lowering efficacy of antihypertensive medications.

Further evidence that methods based on spot urine samples should not be used to examine sodium‐disease relationships from the Science of Salt: A regularly updated systematic review of salt and health outcomes (November 2018 to August 2019)

“…Studies assessed for eligibility were meta‐analyses (n = 3), prospective cohort studies (n = 10), cross‐sectional studies (n = 9), post hoc analyses of RCT’s (n = 1), quasi‐experimental studies (n = 2), and modeling analyses (n = 2). Three studies assessed mortality outcomes, 22‐24 six studies assessed morbidity outcomes, 25‐30 15 studies assessed clinically relevant surrogate outcomes, 31‐45 including 12 that assessed blood pressure outcomes, 31‐34,38‐45 and three studies assessed physiologic outcomes 46‐48 . Of these studies, only two met the minimum methodological criteria for detailed critical appraisal (Table 1).…”

Prevalence and characteristics of isolated nocturnal hypertension in the general population

“…The procedure for participant recruitment and the measurement protocols have been described in detail elsewhere [ 6 , 7 ]. The original study was designed to evaluate the association between salt intake and BP.…”

Urine Cell Transcriptomes Implicate Specific Renal Inflammatory Pathways Associated With Difficult‐to‐Control Hypertension

“…Higher sodium intake is also associated with elevated BP 40 , 41 , 42 and may be related to decreased efficacy of antihypertensive medication. 43 We observed that the 24‐hour urine sodium excretion was similar between groups and tended to be lower in the BP‐difficult group (Table 1 ), suggesting that difficulty in lowering BP was not attributed to higher sodium intake. Lastly, the groups had similar estimated glomerular filtration rates and essentially no proteinuria (24‐hour urine protein:creatinine ratio of 0.12), which excludes differences in kidney function or glomerular damage as causes for the observed differential gene expression.…”