Nocturnal Urine Production in Women With Global Polyuria.

PURPOSE: Low nocturnal urine production (NUP) may be sufficient to rule out global polyuria (GP) in men. This study determines the sensitivity of indices for nocturnal polyuria (NP), defined as nocturnal polyuria index (NPi; nocturnal urine volume/24-hour urine volume) ≥0.33 or NUP ≥90 mL/hr, for detecting GP in women. METHODS: Data were analyzed from 2 prospective protocols involving subjects recruited from a urology ambulatory care unit and a continence clinic. Women ≥18 years with nocturia were included if they met either of 2 common criteria for GP: (1) ≥40 mL/kg/24 hr or (2) ≥3,000 mL/24 hr. RESULTS: Thirty-one women were included (NPi, 28.6 [21.3-40.7]; NUP, 100.8 [68.3-135.8] mL/hr). At the ≥40 mL/kg/24-hr cutoff, 40% and 63% of women reporting ≥1 nocturnal void(s) (n=30) had NPi ≥0.33 and NUP ≥90 mL/hr, respectively. Additionally, 53% and 71% of subjects reporting ≥2 nocturnal voids (n=17) had NPi ≥0.33 and NUP ≥90 mL/hr, respectively. At the ≥3,000 mL/24-hr cutoff, 38% and 69% of women reporting ≥1 nocturnal void(s) (n=13) had NPi ≥0.33 and NUP ≥90 mL/hr, respectively, and 63% and 88% of subjects reporting ≥2 nocturnal voids (n=8) had NPi ≥0.33 and NUP ≥90 mL/hr, respectively. By extension, 37%-62% of women with nocturia and GP did not have NP by NPi ≥0.33 criteria, and 12%-37% did not have NP by NUP ≥90 mL/hr criteria. CONCLUSION: Indices of excess nighttime urination do not reliably predict GP in women. A full-length voiding diary may be particularly important in the evaluation of women with nocturia. Nocturia in women merits further consideration as a distinct entity.

Could Evening Dietary Protein Intake Play a Role in Nocturnal Polyuria?

Urea is the most abundant and the largest contributing factor for urine osmolality. Urinary urea excretion is highly interrelated with dietary protein intake. Accordingly, an increase of urinary urea excretion due to high protein diet may lead to urea-induced osmotic diuresis. This study aims to explore the association between nocturnal polyuria (NP) and urea. This is a post hoc analysis of a prospective observational study of subjects who completed a renal function profile between October 2011 and February 2015 (n = 170). Each subject underwent a 24 h urine collection, which included 8 urine samples collected at 3 h intervals. Urine volume, osmolality, creatinine, urea and sodium were determined. Urinary urea excretion was used to estimate dietary protein intake. Compared to the control group, subjects with NP exhibited significantly higher nighttime urea and sodium excretion. Estimated evening dietary protein intake was correspondingly significantly higher amongst the NP subgroup. Nighttime diuresis rate was positively associated with age and nighttime free water clearance, creatinine clearance, sodium excretion, and urea excretion in NP subjects. Therefore, increased nocturnal urinary urea excretion may reflect an additional important mediator of nocturia owing to excess nocturnal urine production.

Impact of food and drinks on urine production: A systematic review.

CONTEXT: The impact of food and drinks on body fluid metabolism is of direct clinical relevance but current evidence remains fragmented. AIM: Synthesise current evidence on the role of food and drinks in urine production. METHODS: Systematic review as per PRISMA guidelines using MEDLINE and EMBASE databases (completed October 2019). Studies reporting on the effect of food, food constituents, and drinks on urine production were included. Two authors performed an independent extraction of relevant articles using predetermined data sets and completed quality-of-study indicators. RESULTS: A total of 49 studies were included, of which 21 enroled human subjects, and 28 were clinically relevant animal studies (all of which utilised rodent models). The included studies were determined to be of variable quality. High dietary sodium, as well as wine, spirits, high-caffeine coffee, and caffeinated energy drinks, increased urine production in human studies. Decreased urine production was associated with low dietary sodium and consumption of milk, orange juice, and high-salt/high-sugar drinks. In animal models, a variety of fruits, vegetables, herbs, spices, and honey were associated with increased urine production. CONCLUSION: Current evidence suggests that although several types of food and drinks may impact body fluid metabolism, the quality of the data is variable. Urine production appears to be influenced by multiple factors including composition (ie, moisture, macronutrients, and electrolytes), metabolite load, and the presence of specific diuresis-promoting substances (eg, caffeine, alcohol) and other bioactive phytochemicals. Future research is needed to support current evidence and the physiologic mechanisms underlying these findings.

Dietary considerations in the evaluation and management of nocturia.

Aim: This narrative review investigates the effect of dietary intake on nocturnal voiding severity. The primary aims of this review are to provide a framework for future research and ultimately contribute to more comprehensive, lifestyle-centered guidelines for the management of nocturia. Methods: A literature search was conducted in Web of Science, PubMed, and Google Scholar databases using the keywords "nocturia", "diuresis", "natriuresis", "food", "diet", and "nutrients". Results: High fruit and vegetable consumption was negatively associated with nocturia. High intake of tea and dietary sodium showed a positive association with nocturia. Several foods have also been directly linked to changes in diuresis rate, glycemic control, and endogenous serum melatonin concentration, offering potential mechanisms for this observed effect. Overall quality of the evidence was low. Conclusion: At present, there is limited evidence to suggest that certain foods, electrolytes, and specific compounds may contribute to the pathogenesis of nocturia. A greater understanding of the impact of food and nutrients on body fluid metabolism is needed to further refine the evaluation and treatment of nocturia.

Sodium restriction improves nocturia in patients at a cardiology clinic.

This study aims to determine whether dietary sodium restriction counseling decreases nocturnal voiding frequency in cardiology patients with concomitant nocturia. Patients who had established care at a cardiology clinic from 2015 to 2018 reporting ≥1 average nocturnal void(s) underwent a comprehensive sodium intake interview by their cardiologist, who provided them with individualized strategies for dietary sodium reduction and assessed adherence at follow-up. Average nocturnal voiding frequency and dietary adherence were documented in the medical record. A nocturia database was compiled for retrospective analysis. A total of 74 patients were included. Patients considered to be adherent with dietary sodium restriction at follow-up (n = 56) demonstrated a decrease in median nocturia frequency (2.5 [2.3-3.0] vs 1.0 [1.0-2.0] voids, P < .001). Among nonadherent patients (n = 18), median nocturia frequency did not significantly change from baseline to follow-up (2.0 [1.5-3.8] vs 2.0 [1.5-4.8] voids, P = .423). Median changes were significantly different between the adherent and nonadherent groups (P < .001). Examination of second follow-up available from 37 patients showed a continued effect. In conclusion, adherence with dietary sodium counseling appears to improve nocturia. Accordingly, dietary modification may represent an important adjunct therapy to lifestyle and pharmacologic interventions for decreasing nocturia frequency. Reduction in nocturnal voiding frequency may also reflect an additional benefit of dietary sodium restriction in accordance with best practice standards for cardiovascular disease.

Haptoglobin 1-1 phenotype: A risk factor for 24-hours polyuria.

BACKGROUND: Haptoglobin (Hp) displays three major phenotypes (Hp 1-1, Hp 2-2 and Hp 2-1). Hp 1-1 has been implicated in high blood pressure and salt sensitivity, and thus may mediate excess urine production. AIM: To explore the relationship between Hp polymorphisms and polyuria (>40 mL/kg/24 hours). METHODOLOGY: Post hoc analysis of a prospective observational study of subjects who completed a renal function profile between October 2011 and February 2015 (n = 170). Hp phenotypes were determined by starch gel electrophoresis using haemoglobin-supplemented serum. The distribution of Hp phenotypes in subjects with and without polyuria was compared to a reference group of the same geography and ethnic composition. Diuresis rate, sodium clearance and free water clearance were compared within and between phenotypes. RESULTS: The Hp1 allele frequency was significantly overexpressed in subjects with polyuria compared to the reference group (0.500 vs 0.400, P < .05). Consistently, the Hp 1-1 phenotype was more prevalent in subjects with polyuria compared to the reference group (28% vs 16%, P < .05). In contrast to Hp 2-1/2-2, Hp 1-1 demonstrated no circadian variation in diuresis rate, sodium clearance or free water clearance. A significant association between plasma Hp concentration and 24-hours sodium clearance was observed in Hp 1-1 subjects without polyuria (ß = 0.222; 95% CI 0.003-0.441; P = .047). CONCLUSION: The Hp1 allele was more frequent in subjects with polyuria, and participants with the Hp 1-1 phenotype were at greater risk for polyuria. Hp 1-1 subjects demonstrated an altered ability to concentrate urine with a slower continuous excretion of sodium throughout the day. Plasma Hp concentration of Hp 1-1 was positively correlated with 24-hours sodium clearance in subjects without polyuria.