The prevalence and predictive factors of nocturnal polyuria in Japanese patients with nocturia: a multicentral retrospective cohort study.

The aims of this study were to determine the prevalence and predictors of nocturnal polyuria (NP) in Japanese patients. This multicentral, observational study enrolled patients with the chief complaint of nocturia at 17 Japanese institutions between January 2018 and December 2022. The frequency of daily voiding and volume of urination were evaluated using bladder diaries. NP was diagnosed in patients with an NP index of > 33%. The primary endpoint was NP prevalence in patients with nocturia. The secondary endpoints were the prevalence of NP according to sex and age and the identification of factors predicting NP. This study analyzed 875 eligible patients. NP was present in 590 (67.4%) patients, with prevalence rates of 66.6% and 70.0% in men and women, respectively. Age ≥ 78 years, body mass index (BMI) < 23.0 kg/m2, and patients with ischemic heart or cerebrovascular disease were significant predictors of NP (P < 0.001, P < 0.001, P = 0.014, P = 0.016, respectively). This is the first large multicenter study to investigate the prevalence of NP in Japanese patients with nocturia. NP has a prevalence of 67.4%. Significant predictors of NP include age, BMI, and cardiovascular disease.

Nocturnal polyuria in women: results from the EpiNP study.

INTRODUCTION AND HYPOTHESIS: Data from a large US population-based, cross-sectional, epidemiological study (the EpiNP Study) were used to assess the symptoms and bother experienced by women with nocturnal polyuria (NP). METHODS: Consenting participants recruited from an online panel completed the baseline EpiNP survey online (Lower Urinary Tract Symptoms Tool and urological comorbidities). All reporting ≥2 voids/night and a random sample of 100 respondents, each reporting 0 or 1 void/night were asked to complete a 3-day web-based bladder diary recording time, volume, and urgency rating of each void. NP was calculated by the proportion of urine production that occurred during nocturnal hours using a Nocturnal Polyuria Index (NPI33) threshold of >0.33 or nocturnal urine production of >90 ml/h (NUP90). The frequency of participants reporting LUTS and bother was determined by age and NP: idiopathic NP, NP associated with overactive bladder (NPOAB), NP associated with comorbidities (NPCom), and no NP (did not meet NP criteria). RESULTS: A total of 5,290 women completed the baseline survey. Mean age (range) was 54.9 (30-95) years; 1,841 (34.8%) reported ≥2 nocturnal voids. The prevalence of LUTS increased across the lifespan; however, bother associated with each LUTS decreased with increasing age. The percentage of women rating bother by nocturia episodes ≥2 "> somewhat" ranged from 40.3% to 68.3%, with bother ratings highest in the NPOAB and No NP groups. CONCLUSIONS: NP is prevalent in women with considerable bother and is often associated with other urinary symptoms. Multifactorial causes and potential treatments of NP should be considered, particularly at a later age.

Polyuria in patients with lower urinary tract symptoms: Prevalence and etiology.

INTRODUCTION: Patients with lower urinary tract symptoms (LUTS) can be subcategorized into polyuria, normal or oliguria groups. Polyuria may be caused by pathologies including diabetes mellitus (DM), chronic kidney disease (CKD), diabetes insipidus (DI), or primary polydipsia (PPD). While fluid restriction is appropriate for some, doing so in all may result in serious complications. This study investigates the prevalence of these pathologies in LUTS patients with polyuria. MATERIALS AND METHODS: Two databases were retrospectively queried for men and women who filled out a lower urinary tract symptom score (LUTSS) questionnaire, 24-h bladder diary (24HBD) and were polyuric (>2.5 L/day). Patients were divided into four groups: poorly controlled DM, DI, an CKD grade 3 and PPD. One-way analysis of variance compared 24HBD and LUTSS questionnaires. Pearson correlation examined LUTSS and bother with 24-h voided volume (24 HVV), maximum voided volume (MVV) and total voids. RESULTS: Among 814 patients who completed a 24HBD, 176 had polyuria (22%). Of the patients with complete data, 7.8% had poorly-controlled DM, 3.1% had DI, 4.7% had CKD grade 3% and 84.4% had PPD. Amongst the four different sub-groups, significant differences were seen in 24 HVV (p < 0.001), nocturnal urine volume (NUV) (p < 0.001), MVV (p = 0.003), daytime voids (p = 0.05), nocturnal polyuria index (NPi) (p < 0.001) and nocturia index (Ni) (p = 0.002). Significance was also seen between LUTSS and bother subscore (r = 0.68, p < 0.001), LUTSS and total voids (r = 0.29, p = 0.001) and bother sub-score and total voids (r = 0.21, p = 0.019). CONCLUSIONS: 22% of patients with LUTS were found to have polyuria based on a 24HBD. Within this cohort, four sub-populations were identified as being demonstrating statistically significant differences in 24 HVV, NUV, MVV, daytime voids, NPi and Ni. Identifying the underlying etiology of polyuria should be carried out to safely treat patients with LUTS.

Analysis of changes in the pathophysiology of nocturia according to the number of nocturia episode, age, and gender using frequency volume charts: A retrospective observational study.

PURPOSE: To evaluate the pathophysiology of nocturia based on the frequency volume chart, and determine the risk factors for nocturia occurring ≥2 times per night. MATERIALS AND METHODS: In this retrospective study, we reviewed 311 patients with complaints of nocturia from January 2017 to February 2019 at our institution. Nocturnal polyuria (NP) and global polyuria (GP) were defined as NP index >0.35 regardless of age and 24 h urine volume >2.5 L/day, respectively. Decreased bladder capacity (dBC) was when the maximal voided volume was <325 mL. Decreased nocturnal bladder capacity (dNBC) was defined as nocturnal bladder capacity index >0. RESULTS: In total, 273 patients were included in the primary analyses. Of 802 days from 273 frequency volume charts, the median number of nocturia was 1 episode per day. Further, NP (odds ratios [OR] 7.01), GP (OR 4.25), dBC (OR 3.00), dNBC (OR 10.12), and age (OR 1.04) had the association with nocturia ≥2 times per night. There was a significant stepwise increase in NP, dNBC, dBC, and GP with the number of nocturia episodes. As patient age increased, the likelihood of NP (P < 0.001) and dBC (P < 0.001) being the cause for nocturia tended to increase, but that of dNBC (P = 0.022) and nocturia without cause (P = 0.007) tended to decrease. Moreover, dBC was more likely to cause nocturia in female patients than in male patients (P < 0.001). CONCLUSION: NP, dBC, dNBC, and GP are important factors involved in the pathophysiology of nocturia occurring ≥2 times per night.

Prevalence and predictors of nocturnal polyuria in females with overactive bladder syndrome.

PURPOSE: To describe the prevalence and predictors of nocturnal polyuria (NP) in women with overactive bladder syndrome (OAB). METHODS: Between July 2009 and January 2018, women with OAB were enrolled. NP was defined when the nocturnal polyuria index (NPI) (nighttime voided volume over 24-h voided volume) was > 33% (NPI33) in women ≥ 65 years-old and > 20% (NPI20) in women < 65 years old. Repeated analysis was also performed for NP defined by the NPI33 definition at all ages. RESULTS: A total of 1071 women with OAB were analyzed. The overall prevalence of NP was 30% (319/1071), with the highest prevalence in women in the perimenopausal period (46-50 years old), while NP was diagnosed by age-dependent NPI. The overall prevalence of NP was 12% (128/1071), with an increasing trend with increasing age, while NP was diagnosed by the NPI33 definition only. Daytime frequency and nocturia episodes were both predictors for NP in both definitions. Receiver operating characteristic curve analysis revealed that more than 5 nocturia episodes noted in the 3-day bladder diary were an optimal cutoff value to predict nocturnal polyuria [(sensitivity = 85.6%, specificity = 61.0%; area = 0.80, 95% CI 0.77-0.82) and (sensitivity = 88.3%, specificity = 65.9%; area = 0.83, 95% CI 0.80-0.85), respectively, in the two definitions]. CONCLUSIONS: NP is common in women with OAB, especially in women with more than 5 nocturia episodes in their 3-day bladder diaries, and adjuvant therapy for better treatment efficacy is needed.

Nocturnal polyuria in men performing uroflowmetry for lower urinary tract symptoms.

PURPOSE: To assess the prevalence of nocturnal polyuria (NP) in males performing uroflowmetry (UF) for lower urinary tract symptoms (LUTS), the impact of NP on UF outcomes, and bladder emptying, the association between NP and LUTS. MATERIALS AND METHODS: Men scheduled for UF were recruited in two Centres. Data collected were medical history, IPSS, UF, post-void residual urine volume (PVR), 3-day frequency-volume charts (FVC). The NP index was used to assess NP with a threshold of ≥ 33%. The relationship between NP and patient's aging was assessed. RESULTS: 162 patients were included in the analysis. Mean age was 70.95 ± 8.04 years. The prevalence of NP was 54.9% (89/162). 110 (68%) patients reported nocturia, and among these, NP was documented in 76 (69%). Nocturia was found in 85% (76/89) of the population with NP. Total IPSS score, IPSS items #1, #2 and #7 showed a significant difference in men with NP compared with those without. Maximum flow rate and PVR did not significantly change comparing men with or without NP. Mean voiding volume (VV) of the night-time micturitions was significantly higher in men with NP compared to those without NP (532.1 ± 275.6 ml vs 175 ± 168.7 ml respectively, p < 0001), while mean VV day-time micturitions and mean VV at UF did not change between groups. CONCLUSIONS: NP had a high prevalence in men with LUTS performing UF. Aged males were more commonly affected by NP. Data demonstrated a strong relationship between NP and nocturia and increased urinary frequency while voiding symptoms were poorly related to NP.

Acquired forms of central diabetes insipidus: Mechanisms of disease.

Most cases of acquired central diabetes insipidus are caused by destruction of the neurohypophysis by: 1) anatomic lesions that destroy the vasopressin neurons by pressure or infiltration, 2) damage to the vasopressin neurons by surgery or head trauma, and 3) autoimmune destruction of the vasopressin neurons. Because the vasopressin neurons are located in the hypothalamus, lesions confined to the sella turcica generally do not cause diabetes insipidus because the posterior pituitary is simply the site of the axon terminals that secrete vasopressin into the bloodstream. In addition, the capacity of the neurohypophysis to synthesize vasopressin is greatly in excess of the body's needs, and destruction of 80-90% of the hypothalamic vasopressin neurons is required to produce diabetes insipidus. As a result, even large lesions in the sellar and suprasellar area generally are not associated with impaired water homeostasis until they are surgically resected. Regardless of the etiology of central diabetes insipidus, deficient or absent vasopressin secretion causes impaired urine concentration with resultant polyuria. In most cases, secondary polydipsia is able to maintain water homeostasis at the expense of frequent thirst and drinking. However, destruction of the osmoreceptors in the anterior hypothalamus that regulate vasopressin neuronal activity causes a loss of thirst as well as vasopressin section, leading to severe chronic dehydration and hyperosmolality. Vasopressin deficiency also leads to down-regulation of the synthesis of aquaporin-2 water channels in the kidney collecting duct principal cells, causing a secondary nephrogenic diabetes insipidus. As a result, several days of vasopressin administration are required to achieve maximal urine concentration in patients with CDI. Consequently, the presentation of patients with central diabetes insipidus can vary greatly, depending on the size and location of the lesion, the magnitude of trauma to the neurohypophysis, the degree of destruction of the vasopressin neurons, and the presence of other hormonal deficits from damage to the anterior pituitary.

Central diabetes insipidus in children: Diagnosis and management.

Central diabetes insipidus (CDI) is a complex disorder in which large volumes of dilute urine are excreted due to arginine-vasopressin deficiency, and it is caused by a variety of conditions (genetic, congenital, inflammatory, neoplastic, traumatic) that arise mainly from the hypothalamus. The differential diagnosis between diseases presenting with polyuria and polydipsia is challenging and requires a detailed medical history, physical examination, biochemical approach, imaging studies and, in some cases, histological confirmation. Magnetic resonance imaging is the gold standard method for evaluating the sellar-suprasellar region in CDI. Pituitary stalk size at presentation is variable and can change over time, depending on the underlying condition, and other brain areas or other organs - in specific diseases - may become involved during follow up. An early diagnosis and treatment are preferable in order to avoid central nervous system damage and the risk of dissemination of germ cell tumor, or progression of Langerhans Cell Histiocytosis, and in order to start treatment of additional pituitary defects without further delay. This review focuses on current diagnostic work-up and on the role of neuroimaging in the differential diagnosis of CDI in children and adolescents. It provides an update on the best approach for diagnosis - including novel biochemical markers such as copeptin - treatment and follow up of children and adolescents with CDI; it also describes the best approach to challenging situations such as post-surgical patients, adipsic patients, patients undergoing chemotherapy and/or in critical care.

Prevalence of the nocturnal polyuria syndrome in men.

AIMS: Nocturnal polyuria (NP) is caused by a wide array of factors, including genitourinary and systemic comorbidities, modifiable behavior, and pharmaceuticals. When an identifying factor is absent, NP may be purely a symptom of the nocturnal polyuria syndrome (NPS) and secondary to blunting of normal arginine vasopressin action within the circadian rhythm. The purpose of this study is to determine the prevalence of NPS in male patients attending a Veterans Affairs outpatient urology clinic. METHODS: Retrospective database analysis was performed of voiding diaries from men who had established care for lower urinary tract symptoms from 2007 to 2018. Patients were excluded if they reported fewer than two nocturnal voids on voiding diary analysis or had comorbidity associated with NP. Distinct cutoffs were separately employed to identify NP: nocturnal polyuria index (NPi; calculated as nocturnal urine volume divided by 24-hour urine volume) greater than 0.33; and nocturnal urine production (NUP) greater than 90 mL/h. RESULTS: A total of 283 completed voiding diaries were evaluated and 202 patients had ≥2 nocturnal voids. After exclusions, at NPi greater than 33, the floor and ceiling NPS prevalence values were 21% and 41%, respectively. At NUP greater than 90 mL/h, the floor and ceiling NPS prevalence values were 17% and 32%, respectively. CONCLUSIONS: The prevalence of NPS in patients with nocturia in the present study lies between 17% and 41%. NPS constitutes a clinically relevant subgroup of nocturia among male patients in the Veterans Affairs outpatient urology setting.

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.

Nocturia and Nocturnal Polyuria in Neurological Patients: From Epidemiology to Treatment. A Systematic Review of the Literature.

CONTEXT: Nocturia is among the most common and bothersome lower urinary tract symptoms (LUTS), but there is no clear consensus on how to identify and manage this symptom in the neurological population. OBJECTIVE: To systematically review the literature about nocturia in neurological patients. EVIDENCE ACQUISITION: Studies were identified by electronic search of Cochrane and Medline databases. The studies were included if their participants had acquired neurological pathology among multiple sclerosis (MS), Parkinson's disease (PD), stroke, spinal cord injury (SCI), and reported data on the epidemiology, aetiology, diagnosis, or treatment of nocturia. An independent extraction of the articles was performed by two authors using predetermined datasets, including quality-of-study indicators. EVIDENCE SYNTHESIS: A total of 132 studies were included; 46 evaluated the epidemiology of nocturia, 28 the possible aetiologies, 10 the diagnostic tools, and 60 the treatments. Nocturia prevalence ranged from 15% to 96% depending on the pathology and definition used. It was one of the most frequently reported LUTS in PD and stroke patients. Several validated questionnaires were found to screen for nocturia in this population. Causalities were numerous: LUT, renal, sleep, cardiovascular dysfunctions, etc. Treatments targeted these mechanisms, with an overall risk of bias assessed as high or serious. The highest level of evidence was seen in MS patients: pelvic floor muscle training, cannabinoids, and desmopressin were effective, but not melatonin. In stroke patients, transcutaneous sacral and transcutaneous tibial nerve stimulation (TTNS) improved nocturia; in PD patients, TTNS, solifenacin, and rotigotine did not. CONCLUSIONS: Nocturia is highly prevalent in patients with neurological disorders. Causalities and treatments are not different from the general population, but are poorly studied in neurological patients. PATIENT SUMMARY: In this report, we looked at the published studies about nocturia-the fact of waking to void during the hours of sleep-in patients with neurological diseases. We found that nocturia is very frequent in this population, that the causes are the same as in the general population but may be combined, and that treatments are also the same but have an overall weak level of evidence. We conclude that more research is needed on this topic.

Future Considerations in Nocturia and Nocturnal Polyuria.

Nocturnal polyuria (NP), the most common etiology of nocturia, can be caused by various medical conditions, including cardiovascular disease, obstructive sleep apnea, renal tubular dysfunction, as well as medications (eg, diuretics) and/or behavioral patterns. NP in the absence of underlying medical conditions has been described as NP syndrome and is thought be the result of impaired circadian release of endogenous arginine vasopressin. Desmopressin, a synthetic arginine vasopressin analog, has been shown to be an effective replacement therapy in adults with nocturia due to NP. Further studies on the subset of patients with NP syndrome are warranted to maximize benefit from antidiuretic treatment. In addition, a connection between the pathophysiological mechanisms underlying NP and essential hypertension has been suggested, and hypertension has been shown to be a significant risk factor for nocturia, while an association between NP and brain natriuretic peptide levels has also been reported in patients with nocturia. Hypertension is now viewed as a disorder of blood vessels and treatment is directed at the vasculature rather than the blood pressure, with the latter currently serving as a biomarker for arterial injury. Nocturia is thought to be associated with the beginning of this cardiovascular continuum as studies have reported a link between coronary heart disease and nocturia. Therefore, there is an increasing need to elucidate the complex mechanisms implicated in the association between nocturia and hypertension to promote the development of more individualized therapies for the treatment of nocturia.

Managing nocturia: The multidisciplinary approach.

Nocturia, defined as waking at night to pass urine, is a common condition which increases with age. Whilst nocturia is known to have an important effect on quality of life, more recent evidence has linked the symptom with significant morbidity and mortality due to the effects of sleep deprivation on glucose metabolism and the immune system. The causes of nocturia are multifactorial and may be related to urine overproduction, storage disorders and primary sleep disorders. The commonest underlying pathology, however, is nocturnal polyuria, which may be associated with a number of medical conditions. This review explores the underlying causes of nocturia and nocturnal polyuria and, by doing so, describes a multidisciplinary approach to managing patients effectively.

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.

Inhibidores del cotransportador sodio-glucosa tipo 2 y síntomas del tracto urinario inferior en varones, un aspecto a considerar / Sodium glucose cotransporter 2 inhibitors and males lower urinary tract symptoms, an aspect to consider

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Nephrocalcinosis among children at king hussein medical center: Causes and outcome.

Nephrocalcinosis (NC) is defined as deposition of calcium crystals in the renal parenchyma and tubules. This is a retrospective review of all the data of 63 children presented to Pediatric Nephrology Clinic at King Hussein Medical Center (KHMC) over a 15-year period with bilateral NC. We determine their causes, clinical presentation and evaluate their growth and renal function during their follow-up. Thirty-five (55.5%) cases were males and 28 (44.5%) were females. The median (range) age at presentation was four (2-192) months. The most common leading cause to NC was hereditary tubulopathy in 48% followed by hyperoxaluria in 35%. The cause of NC remained unknown in 3% and Vitamin D excess accounts for 5% of the cases. The most presenting symptom was a failure to thrive (68%) and the second most common symptom was abdominal pain and recurrent urinary tract infection was found in 40%, polyuria and polydipsia were found in 32% of cases, and 16% of cases were diagnosed incidentally. At a median follow-up of 38 (14-200) months, estimated glomerular filtration rate had decreased from 84.0 (42-110) mL/min per 1.73 m2 body surface area to 68.2 (10-110) mL/min/1.73 m2 body surface (P = 0.001). This study illustrated the need for a national registry of rare renal diseases to help understand the causes of these conditions in our populations and provide support to affected patients and their families.

Does the Age of Donor Kidneys Affect Nocturnal Polyuria in Patients With Successful Real Transplantation?

BACKGROUND: We investigated whether the age of donor kidneys influences the incidence of nocturnal polyuria in patients with successful renal transplantation (RTX). METHODS: Eighty-five patients (45 men and 40 women) undergoing RTX (median age, 47 years) were included in this study. Twenty-four-hour bladder diaries were kept for 3 days, and nocturnal polyuria was defined as a nocturnal polyuria index (nocturnal urine volume/24-hour urine volume) of >0.33. Risk factors for nocturnal polyuria were analyzed in patients with RTX by means of the Mann-Whitney U test, χ2 test, and a logistic regression analysis. RESULTS: End-stage renal disease (ESRD) developed from diabetes mellitus in 16 patients (19%). Sixty-five patients (76%) received pre-transplant dialysis, with a median duration of 5 years. The median serum creatinine level and body mass index at the most recent visit were 1.2 mg/dL and 21.2 kg/m2, respectively. On the basis of the 24-hour bladder diaries, nocturnal polyuria was identified in 48 patients (56%). A logistic regression analysis revealed that diabetes mellitus as the original disease for ESRD was the only risk factor for nocturnal polyuria (odds ratio, 8.95; 95% confidence interval, 2.01-65.3; P = .0028). The age of donor kidneys at examination did not affect the incidence of nocturnal polyuria (P = .9402). CONCLUSIONS: Nocturnal polyuria was not uncommon in patients with successful RTX. Diabetes mellitus as the original disease for ESRD was the only risk factor for nocturnal polyuria, whereas the age of donor kidneys at examination did not affect the incidence of nocturnal polyuria. Thus, nocturnal polyuria is caused by recipient factors but not donor factors.

Diurnal blood pressure and urine production in acute spinal cord injury compared with controls.

STUDY DESIGN: This is a prospective observational study. OBJECTIVES: The objective of this study was to determine time-dependent changes in diurnal blood pressure (BP) and urine production in acute spinal cord injury (SCI). SETTING: This study was conducted in a specialist, state-based spinal cord service in Victoria, Australia. METHODS: Consenting patients admitted consecutively with acute SCI were compared with patients confined to bed rest while awaiting surgery and with mobilising able-bodied controls. Participants underwent ambulatory BP monitoring (ABPM), measurement of diurnal urine production and rated orthostatic symptoms over 1 year. Participants with night:day systolic BP (SBP) <90% were classified as dippers, 90-100% as non-dippers and >100% as reverse dippers. RESULTS: Participants comprised tetraplegics (n=47, 40.0±17.3 years), paraplegics (n=35, 34.4±13.9 years), immobilised (n=18, 30.9±11.3 years) and mobilising (n=44, 33.1±13.5 years) controls. At baseline, 24-h BP was significantly lower in tetraplegics (111.8±1.9/62.1±1.1 mm Hg) but not in paraplegics (116.7± 1.4/66.0±1.1 mm Hg), compared with controls (117.1 ±1.3/69.1±1.1 mm Hg), adjusting for gender. This difference was not observed at 1 year. The average night:day SBP in mobilising controls was 86.1±0.7%, differing from paraplegics (94.0±1.5%, P<0.001) and tetraplegics (101.5±1.5%, P<0.001). Urine production in tetraplegics and paraplegics did not fall at night compared with the day. Abnormal diurnal BP and orthostatic symptoms in tetraplegics persisted throughout the study. Nocturnal hypertension was observed in 27% (n=9) of tetraplegics, of whom only 2 had day hypertension. All mobilising controls with nocturnal hypertension (n=6, 14%) had day hypertension. CONCLUSION: People with SCI have a high prevalence of isolated nocturnal hypertension, reverse dipping, orthostatic intolerance and nocturnal polyuria. Cardiovascular risk management and assessment of orthostatic symptoms should include ABPM.