A cutoff value based on analysis of a reference population decreases overestimation of the prevalence of nocturnal polyuria

Nocturia: its characteristics, diagnostic algorithm and treatment

Nocturia is the complaint that an individual has to wake up at night one or more times to urinate. It is a frequent condition among older adults and entails detrimental effects with regard to sleeping, sexual activity, comfort, depression, mental function and vitality. It is clinically important to distinguish it from global polyuria, defined as a urinary rate ≥ 125 ml/h (3000 ml/day), as well as from nocturnal polyuria, which is an abnormally large volume of urine during sleep associated with a decreased daytime urine production. A Frequency Volume Chart (FVC), overnight water deprivation test with renal concentrating capacity test, and the nocturnal bladder capacity index are some of the methods that help establish the underlying pathology of this condition and hence define an adequate treatment plan.

Dietary salt with nitric oxide deficiency induces nocturnal polyuria in mice via hyperactivation of intrarenal angiotensin II-SPAK-NCC pathway

Nocturnal polyuria is the most frequent cause of nocturia, a common disease associated with a compromised quality of life and increased mortality. Its pathogenesis is complex, and the detailed underlying mechanism remains unknown. Herein, we report that concomitant intake of a high-salt diet and reduced nitric oxide (NO) production achieved through N^ω-Nitro-L-arginine methyl ester hydrochloride (L-NAME) administration in mice resulted in nocturnal polyuria recapitulating the clinical features in humans. High salt intake under reduced NO production overactivated the angiotensin II-SPAK (STE20/SPS1-related proline–alanine-rich protein kinase)-NCC (sodium chloride co-transporter) pathway in the kidney, resulting in the insufficient excretion of sodium during the day and its excessive excretion at night. Excessive Na excretion at night in turn leads to nocturnal polyuria due to osmotic diuresis. Our study identified a central role for the intrarenal angiotensin II-SPAK-NCC pathway in the pathophysiology of nocturnal polyuria, highlighting its potential as a promising therapeutic target.

This study reports a mouse model of nocturnal polyuria - increased urine production at night that causes compromised quality of life and may impact mortality in older people. The authors identify a molecular pathway in the kidney that could prove to be a promising drug target for nocturnal polyuria.

Assessment of the Most Impactful Combination of Factors Associated with Nocturia and to Define Nocturnal Polyuria by Multivariate Modelling

BACKGROUND

Nocturia is common and associated with multiple disease states. Many potential mechanisms have been proposed for nocturia, which also remains challenging to manage.

PURPOSE

To use multivariate analysis to determine which combinations of factors can accurately discriminate clinically significant nocturia in patients to facilitate clinical management and treatment decisions.

PATIENTS AND METHODS

Data analysis was based on frequency volume charts from three randomized controlled trials. There were 1479 patients included, of which 215 patients had no/mild nocturia and 1264 had clinically significant nocturia with at least two voids per night. Factors studied that may influence nocturia were demographics, sleep duration, functional bladder capacity, 24 h urine volume and literature-suggested definitions of nocturnal polyuria. We used univariate analysis and cross-validated multivariate modelling to assess association between factors and nocturia status, redundancy between factors and whether the combined use of factors could explain patients' nocturia status.

RESULTS

The multivariate analyses showed that the most useful definitions of nocturia are 'Nocturia Index' (NI) and 'Nocturnal Urine Production per hour' (NUPh) in combination with functional bladder capacity and sleep duration. Published definitions providing binary nocturnal polyuria outcomes had lower performance than continuous indices. These analyses also showed that NI was not specific to nocturnal polyuria as it also captured nocturia due to low functional bladder capacity. By contrast, NUPh was demonstrated to be specific to nocturnal polyuria.

CONCLUSION

NUPh has previously been shown among elderly males to be essential in nocturia and a very valid measure of nocturnal polyuria. However, the current, large and independent dataset now confirms that it can be applied in an adult population with a complaint of nocturia covering both males and females.

Prevalence, subtypes, and correlates of nocturia in the symptoms of Lower Urinary Tract Dysfunction Research Network cohort

AIMS

We determined the prevalence, severity, and correlates of nocturia in a large clinical cohort of patients.

METHODS

Patients presenting with lower urinary tract symptoms (LUTS) completed 3-day bladder diaries. Nocturia was quantified based on the mean number of nighttime voids documented over the 3 days. Nocturia subtypes (global polyuria, nocturnal polyuria [NP], reduced global bladder capacity, and reduced nocturnal bladder capacity) were assessed. Bother due to nocturia was measured by the LUTS Tool. Sleep quality was assessed with the Patient-Reported Outcomes Measurement Information System Sleep Scale. Multivariable multinomial regression was used to explore patient characteristics associated with nocturia.

RESULTS

In 502 participants with analyzable diaries (285 men and 217 women), the mean number of nocturia episodes over 3 days was 0 in 103 (20.5%), >0 to <1 in 151 (20.1%), 1 to <2 in 165 (32.9%), and ≥2 in 83 (16.5%). Sixty-seven percent of the participants with nocturia ≥1 reported significant bother from their nocturia. NP was the most common nocturia subtype and was present in 17% of those with nocturia = 0, 40% of those with nocturia >0 to <1, 65% of those with nocturia 1 to <2%, and 77% with nocturia 2+. Higher degrees of nocturia were associated with male sex, greater sleep disturbance, and a higher likelihood of exhibiting multiple nocturia subtypes.

CONCLUSIONS

Nocturia ≥1 occurred in 49% of LUTS patients and caused significant bother in the majority of them. The most common subtype was NP, but a substantial proportion of patients exhibited additional characteristics.

Current guidelines and treatment paradigms for nocturnal polyuria: A "NEW" disease state for US physicians, patients and payers

Nocturia is one of the most bothersome symptoms encountered in urology, and its prevalence rises with age. Causes include both urological and non-urological aetiologies, often in combination. The effects of nocturia on a patient's quality of life can be detrimental. The initial approach to managing this condition includes appropriately classifying nocturia based on the results of a 24-hour bladder diary. Broadly, the categories under which nocturia can be classified include: low nocturnal or global bladder capacity, nocturnal polyuria, global polyuria and mixed.Based on the type of nocturia and possible underlying causes, clinicians can appropriately discuss with patients the treatment plans that may include a combination of behavioural, pharmacologic, and invasive therapy. The available literature on the management of nocturia was reviewed. Findings were incorporated into a practice-based approach for its workup and treatment.

Nocturnal polyuria: Literature review of definition, pathophysiology, investigations and treatment

Nocturnal polyuria (NP) is characterised by increased urine production overnight in comparison to daytime. It has significant adverse events in adults including reduced quality of life, increased risk of falls and increased mortality.

Although NP can be a manifestation of other significant conditions like heart failure and sleep apnoea, there are lots of unanswered questions about NP. What is the underlying pathophysiology? Is NP a physiological manifestation of ageing? Is the circadian change of vasopressin release the primary pathology? Or is it a secondary phenomenon to a low diurnal production of urine? Is the primary pathology at the kidney level or is there another humoral, cardiac, or endovascular element? In this article, we summarise the available English-language literature on the subject of NP, including its epidemiology, pathogenesis, diagnosis and treatment.

Level of evidence: Not applicable for this multicentre audit.

Systematic review of proposed definitions of nocturnal polyuria and population-based evidence of their diagnostic accuracy

Background Evidence of diagnostic accuracy for proposed definitions of nocturnal polyuria is currently unclear. Purpose Systematic review to determine population-based evidence of the diagnostic accuracy of proposed definitions of nocturnal polyuria based on data from frequency-volume charts. Methods Seventeen pre-specified search terms identified 351 unique investigations published from 1990 to 2016 in BIOSIS, Embase, Embase Alerts, International Pharmaceutical Abstract, Medline, and Cochrane. Thirteen original communications were included in this review based on pre-specified exclusion criteria. Data were extracted from each paper regarding subject age, sex, ethnicity, health status, sample size, data collection methods, and diagnostic discrimination of proposed definitions including sensitivity, specificity, positive and negative predictive value. Results The sample size of study cohorts, participant age, sex, ethnicity, and health status varied considerably in 13 studies reporting on the diagnostic performance of seven different definitions of nocturnal polyuria using frequency-volume chart data from 4968 participants. Most study cohorts were small, mono-ethnic, including only Caucasian males aged 50 or higher with primary or secondary polyuria that were compared to a control group of healthy men without nocturia in prospective or retrospective settings. Proposed definitions had poor discriminatory accuracy in evaluations based on data from subjects independent from the original study cohorts with findings being similar regarding the most widely evaluated definition endorsed by ICS. Conclusions Diagnostic performance characteristics for proposed definitions of nocturnal polyuria show poor to modest discrimination and are not based on sufficient level of evidence from representative, multi-ethnic population-based data from both females and males of all adult ages.

Nocturia: consequences, classification, and management

Nocturia is a widespread condition that can negatively impact quality of sleep and overall health. This condition is multifactorial in nature and is best approached through the analysis of frequency volume charts. Through these charts, clinicians may classify each individual case of nocturia into one of four distinct categories: global polyuria, nocturnal polyuria, reduced bladder capacity, and mixed. Treatments should then be tailored to each individual based upon the category of their nocturia. In some cases, appropriate therapy will consist of behavioral modification techniques or addressing underlying systemic diseases. In other cases, medical therapy may be necessary, but, to date, medications have shown limited efficacy at treating nocturia.

The Prevalence of Nocturia and Nocturnal Polyuria: Can New Cutoff Values Be Suggested According to Age and Sex?

PURPOSE

The aims of this study were to assess the prevalence of nocturia and nocturnal polyuria (NP) and to define new cutoff values according to age and sex for both conditions.

METHODS

Data from a population-based prevalence survey conducted among a random sample of 2,128 adults were analyzed in this study. Participants were requested to fill out a questionnaire including the International Continence Society (ICS) definitions of lower urinary tract symptoms and the International Consultation on Incontinence Questionnaire - Short Form. Additionally, a 1-day bladder diary was given to each individual. The participants were divided into 5 age groups. The prevalence of nocturia was calculated based on definitions of nocturia as ≥1 voiding episodes, ≥2 episodes, and ≥3 episodes. NP was evaluated according to the ICS definition. The mean±standard errors and 95th percentile values were calculated in each group as new cutoff values for NP.

RESULTS

The prevalence of nocturia was estimated as 28.4%, 17.6%, and 8.9% for ≥1, ≥2, and ≥3 voiding episodes each night, respectively. When nocturia was defined as 2 or more voiding episodes at night, the prevalence decreased significantly. The mean NP index was 29.4%±15.0% in men and 23.1%±11.8% in women. For the age groups of <50 years, 50-59 years, and ≥60 years, the new cutoff values for the diagnosis of NP were calculated as 48%, 69%, and 59% for men and 41%, 50%, and 42% for women, respectively.

CONCLUSIONS

We found that the definition of nocturia was still controversial and that waking up once for voiding might be within the normal spectrum of behavior. The definition of NP should be modified, and new cutoff values should be defined using the data presented in our study and in other forthcoming studies.

Nocturia: aetiology and treatment in adults

Nocturia is an extremely common condition that has major sequelae for affected patients. Through disruption of sleep, nocturia impairs quality of life and worsens health outcomes, and is associated with a variety of morbidities including diabetes, coronary artery disease, obstructive sleep apnoea, obesity, metabolic syndrome, and depression. Unsurprisingly, several studies have also linked nocturia with reduced survival. Nocturia is not simply a consequence of lower urinary tract disease; rather, it is a multifactorial disorder that is often a manifestation of an underlying renal or systemic disease. Through the use of the frequency volume chart, clinicians can accurately quantify nocturia and determine its aetiology. Evaluation of quality of life and sleep using simple measures is essential in order to assess the impact of nocturia on a patient. Numerous treatment options for nocturia exist, but most are associated with minor benefit or lack sufficient evidence supporting their use. By systematically analysing an individual's causes of nocturia, clinicians can design appropriate treatment strategies to most effectively treat this condition.

Would a new definition and classification of nocturia and nocturnal polyuria improve our management of patients? ICI-RS 2014

The following is a report of the proceedings of the Nocturia Think Tank sessions of the annual International Consultation on Incontinence-Research Society, which took place September 22-24, 2014 in Bristol, UK. The report is organized into sections pertaining to the main topic of discussion focussing on the question as to whether a new definition and classification of nocturia and nocturnal polyuria would improve the outcome of management in our patients. First, discussions identified theoretical and practical shortcomings of current definitions. Secondly, the utility of several nocturnal polyuria definitions was tested in a real life population in relation to the symptom nocturia, in order to display weaknesses of these definitions. Thirdly, we explored in a clinical population the utility of bladder diary based parameters by asking the question: when nocturia improves, which of these parameters improve most? Based on the above explorations the Think Tank summarized elements of the current definitions that need reconsideration and suggests proposals for further research to reach more practical and more clinically meaningful definitions.

Impact of the International Continence Society (ICS) report on the standardisation of terminology in nocturia on the quality of reports on nocturia and nocturnal polyuria: a systematic review

OBJECTIVE

To systematically review and evaluate the impact of the International Continence Society (ICS)-2002 report on standardisation of terminology in nocturia, on publications reporting on nocturia and nocturnal polyuria (NP). In 2002, the ICS defined NP as a Nocturnal Polyuria Index (nocturnal urine volume/total 24-h urine volume) of >0.2-0.33, depending on age.

MATERIALS AND METHODS

In April 2013 the PubMed and Embase databases were searched for studies (in English, German, French or Dutch) based on original data and adult participants, investigating the relationship between nocturia and NP. A methodological quality assessment was performed, including scores on external validity, internal validity and informativeness. Quality scores of items were compared between studies published before and after the ICS-2002 report.

RESULTS

The search yielded 78 publications based on 66 studies. Quality scores of studies were generally high for internal validity (median 5, interquartile range [IQR] 4-6) but low for external validity. After publication of the ICS-2002 report, external validity showed a significant change from 1 (IQR 1-2) to 2 (IQR 1-2.5; P = 0.019). Nocturia remained undefined in 12 studies. In all, 19 different definitions were used for NP, most often being the ICS (or similar) definition: this covered 52% (n = 11) of studies before and 66% (n = 27) after the ICS-2002 report. Clear definitions of both nocturia and NP were identified in 67% and 76% before, and in 88% and 88% of the studies after the ICS-2002 report, respectively.

CONCLUSION

The ICS-2002 report on standardisation of terminology in nocturia appears to have had a beneficial impact on reporting definitions of nocturia and NP, enabling better interpretation of results and comparisons between research projects. Because the external validity of most of the 66 studies is considered a problem, the results of these studies may not be validly extrapolated to other populations. The ICS definition of NP is used most often. However, its discriminative value seems limited due to the estimated difference of 0.6 nocturnal voids between individuals with and without NP. Refinement of current definitions based on robust research is required. Based on pathophysiological reasoning, we argue that it may be more appropriate to define NP based on nocturnal urine production or nocturnal voided volumes, rather than on a diurnal urine production pattern.