Fluid and electrolyte homeostasis in the elderly: physiological changes of ageing and clinical consequences

Impact of sleep on chronobiology of micturition among healthy older adults

Nocturia (waking to void) is prevalent among older adults. Disruption of the well-described circadian rhythm in urine production with higher nighttime urine output is its most common cause. In young adults, their circadian rhythm is modulated by the 24-h secretory pattern of hormones that regulate salt and water excretion, including antidiuretic hormone (ADH), renin, angiotensin, aldosterone, and atrial natriuretic peptide (ANP). The pattern of hormone secretion is less clear in older adults. We investigated the effect of sleep on the 24-h secretion of these hormones in healthy older adults. Thirteen participants aged ≥65 yr old underwent two 24-h protocols at a clinical research center 6 wk apart. The first used a habitual wake-sleep protocol, and the second used a constant routine protocol that removed the influence of sleep, posture, and diet. To assess hormonal rhythms, plasma was collected at 8:00 am, 12:00 pm, 4:00 pm, and every 30 min from 7:00 pm to 7:00 am. A mixed-effects regression model was used to compare subject-specific and mean trajectories of hormone secretion under the two conditions. ADH, aldosterone, and ANP showed a diurnal rhythm that peaked during sleep in the wake-sleep protocol. These nighttime elevations were significantly attenuated within subjects during the constant routine. We conclude that sleep has a masking effect on circadian rhythm amplitude of ADH, aldosterone, and ANP: the amplitude of each is increased in the presence of sleep and reduced in the absence of sleep. Disrupted sleep could potentially alter nighttime urine output in healthy older adults via this mechanism.NEW & NOTEWORTHY Nocturia (waking to void) is the most common cause of sleep interruption among older adults, and increased nighttime urine production is its primary etiology. We showed that in healthy older adults sleep affects the 24-h secretory rhythm of hormones that regulate salt-water balance, which potentially alters nighttime urine output. Further studies are needed to elucidate the impact of chronic insomnia on the secretory rhythms of these hormones.

Nocturnal polyuria and nocturia

BACKGROUND

Nocturia is a common complaint that can have a significant impact on quality of life. The pathophysiology is usually multifactorial and can be due to poor sleep, nocturnal polyuria, or low bladder capacity alone or in combination.

OBJECTIVE

Nocturnal polyuria (NP) is the most common cause of nocturia in older adults. We hereby review the role of nocturnal polyuria in nocturia.

PATIENTS AND METHODS

To manage nocturia, a multipronged approach personalized to the patient's multifactorial etiology is warranted, with a focus on lifestyle modifications and behavioral approaches as first-line therapies. Pharmacologic treatment should be considered based on underlying disease processes, and healthcare providers should be mindful of potential drug interactions and polypharmacy in older adults.

RESULT

Referral to specialists in sleep or bladder-related disorders may be necessary for some patients. With comprehensive and individualized management, patients with nocturia can achieve improved quality of life and overall health outcomes.

An Up-to-Date Article Regarding Particularities of Drug Treatment in Patients with Chronic Heart Failure

Since the prevalence of heart failure (HF) increases with age, HF is now one of the most common reasons for the hospitalization of elderly people. Although the treatment strategies and overall outcomes of HF patients have improved over time, hospitalization and mortality rates remain elevated, especially in developed countries where populations are aging. Therefore, this paper is intended to be a valuable multidisciplinary source of information for both doctors (cardiologists and general physicians) and pharmacists in order to decrease the morbidity and mortality of heart failure patients. We address several aspects regarding pharmacological treatment (including new approaches in HF treatment strategies [sacubitril/valsartan combination and sodium glucose co-transporter-2 inhibitors]), as well as the particularities of patients (age-induced changes and sex differences) and treatment (pharmacokinetic and pharmacodynamic changes in drugs; cardiorenal syndrome). The article also highlights several drugs and food supplements that may worsen the prognosis of HF patients and discusses some potential drug-drug interactions, their consequences and recommendations for health care providers, as well as the risks of adverse drug reactions and treatment discontinuation, as an interdisciplinary approach to treatment is essential for HF patients.

Benefits of water intake on kidney function in older adults: protocol for a randomized controlled trial

Objective: The goal of this study is to evaluate the benefits of an increase in water intake guided by a mathematical formula (per kg of body weight) on kidney function in older adults. Methods: Older adults (≥ 65 years old) cared for at the Internal Medicine Unit of a tertiary hospital will be randomized to receive or not guidance on water intake (30 mL/kg per day) after initial assessment of kidney function. After 14 days, participants will be reevaluated through clinical and laboratory examinations. Patients with uncompensated disease will be excluded. The main outcomes will be glomerular filtration rate and laboratory measures such as serum and urinary osmolality, sodium, urea, 24-h urine volume and serum creatinine, uric acid, and copeptin. The Mini Nutritional Assessment (MNA) questionnaire will be applied to participants at each visit. Categorical variables will be described as numbers of cases (%) and compared using the χ2 test whereas continuous variables will be analyzed with Student’s t-test in relation to baseline measures. The Generalized Estimating Equations (GEE) method will be performed to assess differences over time and between groups. This study was approved by the Institution’s Research Ethics Committee (grant number 16-0153) and is in accordance with the Declaration of Helsinki. Expected Results:By increasing water intake (ml/Kg) we expect to provide an improvement in kidney function in older population assessed by serum creatinine and cystatin-c applied to eGFR formulas. Relevance:Many conditions, both organic and behavioral, can contribute to chronic dehydration states in older adults. To mention, decreased ability to concentrate urine, reduced kidney mass, blood flow, and glomerular filtration rate (GFR) along with changes in sensitivity to hormones such as renin, vasopressin and natriuretic peptide can generate water imbalance, leading to dehydration. For being simple and inexpensive, this strategy may be broadly used and bring several health benefits to older adults.

Gender-Specific Differences of Renal Heat Tolerance in Older Adults during Heat Waves

BACKGROUND

Heat waves are known to cause increased morbidity and mortality in susceptible populations like old and functionally impaired people. The objective of the study was to assess renal tubular stress, a predictor for development of acute kidney injury, during heat waves in Central Europe. As a marker of renal tubular stress tissue inhibitor of metalloproteinases-2 [TIMP-2]·insulin-like growth factor binding protein-7 [IGFBP7], a new FDA-cleared renal tubular stress biomarker, was used.

MATERIALS AND METHODS

68 residents from facilities of sheltered housing with urine samples collected at heat waves in 2015 and at control visits were included. Urinary [TIMP-2]·[IGFBP7] was compared between the heat waves and the control visits. Multivariate linear models were adjusted for age, frailty index, and functional comorbidity index.

RESULTS

The median age was 82.0 years, 82.3% were women. The percentage of elevated levels of urinary [TIMP-2]·[IGFBP7] (>0.3 [ng/mL]2/1,000) in the total study population was higher at the heat waves than at the control visits (25.0% vs. 17.7%). The effect of the heat waves on urinary [TIMP-2]·[IGFBP7] was stronger in men than in women: The percentage of elevated levels was 75.0% in men and 14.3% in women. In the multivariate analysis, the mean urinary [TIMP-2]·[IGFBP7] was 0.48 (95% CI 0.25; 0.70) (ng/mL)2/1,000 higher in men than in women. Except gender, a number of additional variables did not show an association with urinary [TIMP-2]·[IGFBP7] at the heat waves or the control visits.

CONCLUSIONS

At heat waves, urinary [TIMP-2]·[IGFBP7] was elevated and higher in men than in women. This suggests gender-specific differences in renal heat tolerance in older people.

Effect of maternal age on cardiac adaptation in pregnancy

OBJECTIVE

To compare longitudinal maternal hemodynamic changes throughout gestation between different age groups.

METHODS

This was a prospective longitudinal study assessing maternal hemodynamics using a bioreactance technique at 11 + 0 to 13 + 6, 19 + 0 to 24 + 0, 30 + 0 to 34 + 0 and 35 + 0 to 37 + 0 weeks' gestation. Women were divided into four groups according to maternal age at the first visit at 11 + 0 to 13 + 6 weeks: Group 1, < 25.0 years; Group 2, 25.0-30.0 years; Group 3, 30.1-34.9 years; and Group 4, ≥ 35.0 years. A multilevel linear mixed-effects model was performed to compare the repeat measurements of hemodynamic variables, correcting for demographics, medical and obstetric history, pregnancy complications, maternal age and gestational-age window.

RESULTS

The study population included 254 women in Group 1, 442 in Group 2, 618 in Group 3 and 475 in Group 4. Younger women (Group 1) had the highest cardiac output (CO) and lowest peripheral vascular resistance (PVR), and older women (Group 4) had the lowest CO and highest PVR throughout pregnancy. The higher CO seen in younger women was achieved through an increase in heart rate alone and not with a concomitant rise in stroke volume. Although the youngest age group demonstrated an apparently more favorable hemodynamic profile, it had the highest incidence of a small-for-gestational-age neonate. There was no significant difference between the groups in the incidence of pre-eclampsia.

CONCLUSION

Age-specific differences in maternal hemodynamic adaptation do not explain the differences in the incidence of a small-for-gestational-age neonate between age groups. © 2021 International Society of Ultrasound in Obstetrics and Gynecology.

Acute Hyponatremia Resulting from Duloxetine-induced Syndrome of Inappropriate Antidiuretic Hormone Secretion

A 77-year-old woman who had taken a single oral dose of duloxetine subsequently developed a headache and nausea. On the first day, her serum sodium level was 135 mEq/L. She became confused on the third day. Her serum sodium level was 119 mEq/L and her antidiuretic hormone level was 1.9 IU. We diagnosed her with acute hyponatremia from duloxetine-induced syndrome of inappropriate antidiuretic hormone secretion (SIADH). This case suggests that we must not rule out SIADH on the basis of normal serum sodium levels when a patient who has started serotonin-norepinephrine reuptake inhibitor (SNRI) treatment presents with symptoms similar to hyponatremia.

Pharmacokinetic and pharmacodynamic considerations in the treatment of the elderly patient with hypertension

INTRODUCTION

Hypertension is an important risk factor for developing cardiovascular diseases. It is more prevalent in the elderly population. Recently updated American and European guidelines recommend treating every elderly patient with hypertension independent of age, starting with a low dose of antihypertensive drugs. However, little information is available on the optimal dosages of antihypertensive drugs to treat the elderly safely. Areas covered: Comorbidities, co-medication and frailty status can alter the clinical outcome of drug treatment and can cause adverse events in the elderly. Also, due to pharmacokinetic and pharmacodynamic changes the interpatient variability when using antihypertensive drugs is considerable. In this review, an overview is given on the extent to which the previously mentioned parameters are changed in elderly patients and what this means for the exposure to antihypertensive medication. Also, recommendations on the starting dose of the most frequently used antihypertensive drugs are given based on literature data. Expert opinion: We believe that recommendations on starting dosages followed by a stepwise increase of dosages will lead to improved blood pressure control and less adverse drug reactions in the elderly patient. This may improve adherence to antihypertensive therapy.

Clinical aspects of changes in water and sodium homeostasis in the elderly

The population of elderly individuals is increasing worldwide. With aging, various hormonal and kidney changes occur, both affecting water homeostasis. Aging is a risk factor for chronic kidney disease (CKD) and many features of CKD are reproduced in the aging kidney. Dehydration and hyperosmolarity can be triggered by diminished thirst perception in this population. Elderly with dementia are especially susceptible to abnormalities of their electrolyte and body water homeostasis and should be (re-)assessed for polypharmacy. Hypo- and hypernatremia can be life threatening and should be diagnosed and treated promptly, following current practice guidelines. In severe cases of acute symptomatic hyponatremia, a rapid bolus of 100 to 150 ml of intravenous 3% hypertonic saline is appropriate to avert catastrophic outcomes; for asymptomatic hyponatremia, a very gradual correction is preferred. In summary, the body sodium (Na+) balance is regulated by a complex interplay of environmental and individual factors. In this review, we attempt to provide an overview on this topic, including dehydration, hyponatremia, hypernatremia, age-related kidney changes, water and sodium balance, and age-related changes in the vasopressin and renin-angiotensin-aldosterone system.

The Combined Effect of High Ambient Temperature and Antihypertensive Treatment on Renal Function in Hospitalized Elderly Patients

Background

The aging kidney manifests structural, functional as well as pharmacological changes, rendering elderly patients more susceptible to adverse environmental influences on their health, dehydration in particular.

Hypothesis

Higher temperature is associated with renal function impairment in patients 65 years and older who routinely take thiazide and/or ACE-inhibitors/ARBs.

Methods

We obtained health data of patients older than 65 who were admitted to a large tertiary center during the years 2006–2011, with a previous diagnosis of hypertension, and treated with thiazide, ACE-inhibitors/ARBs or both. We collected environmental data of daily temperature, available from collaborative public and governmental institutions. In order to estimate the effect of daily temperature on renal function we performed linear mixed models, separately for each treatment group and creatinine change during hospital admission.

Results

We identified 26,286 admissions for 14, 268 patients with a mean age of 75.6 (±6.9) years, of whom 53.6% were men. Increment in daily temperature on admission of 5°C had significant effect on creatinine increase in the no treatment (baseline creatinine adjusted 0.824 mg/dL, % change 1.212, % change 95% C.I 0.082–2.354) and dual treatment groups (baseline creatinine adjusted 1.032mg/dL, % change 3.440, % change 95% C.I 1.227–5.700). Sub-analysis stratified by advanced age, chronic kidney disease and primary diagnosis on hospital admission, revealed a significant association within patients admitted due to acute infection and treated with dual therapy.

Conclusion

Whereas previous studies analyzed sporadic climate effects during heat waves and/or excluded older population taking anti-hypertensive medications, the present study is novel by showing a durable association of temperature and decreased renal function specifically in elderly patients taking anti-hypertensive medications.

Review on Mechanisms, Importance of Homeostasis and Fluid Imbalances in the Elderly

Water is considered an essential nutrient, but very often is overlooked in favour of nutrition. Due to age related changes, older people are more vulnerable to both, dehydration and overhydration. This article describes the principles of water homeostasis and provides a description of common age-related physiological changes related to water balance. Fluid homeostasis largely depends on osmo- and baro-receptors that respectively react to changes in osmolality and blood pressure, water-regulating hormone release, the subsequent response of kidneys to the hormonal stimulation and activation of thirst. These mechanisms diminish with age and put elderly at risk of dehydration. All involved in a care for the elderly should be informed and become vigilant to prevent dehydration from occurring.

Aging-related impairment of urine-concentrating mechanisms correlates with dysregulation of adrenocortical angiotensin type 1 receptors in male Fischer rats

To investigate age-associated impairments in fluid homeostasis, 4-mo (young) and 32-mo (old) Fischer 344/BN male rats were studied before and after a dietary sodium load. Transferring young rats from a low-sodium (LS) to a high-sodium (HS) diet increased water intake and urine volume by 1.9- and 3.0-fold, respectively, while urine osmolality and plasma aldosterone decreased by 33 and 98%. Concomitantly, adrenocortical angiotensin type 1 receptor (AT1R) density decreased by 35%, and AT1bR mRNA decreased by 39%; no changes were observed in AT1aR mRNA. In contrast, the increase in water intake (1.4-fold) was lower in the old rats, and there was no effect of the HS diet on urine volume or urine osmolality. AT1R densities were 29% less in the old rats before transferring to the HS diet, and AT1R densities were not reduced as rapidly in response to a HS diet compared with the young animals. After 6 days on the HS diet, plasma potassium was lowered by 26% in the old rats, whereas no change was detected in the young rats. Furthermore, while plasma aldosterone was substantially decreased after 2 days on the HS diet in both young and old rats, plasma aldosterone was significantly lower in the old compared with the young animals after 2 wk on the LS diet. These findings suggest that aging attenuates the responsiveness of the adrenocortical AT1R to a sodium load through impaired regulation of AT1bR mRNA, and that this dysregulation contributes to the defects in water and electrolyte homeostasis observed in aging.

Angiotensin inhibition and longevity: a question of hydration

With the advancement of medical and investigative science, it is somewhat surprising that although it is possible to stabilise medical patients with hypertension and the associated kidney dysfunction, obesity, diabetes and even cancer, there is still no clear method of significantly reducing these chronic disease pathologies, and thus, extending life expectancy. There is one hormone common to these pathologies, the antagonism of which goes some way to clinical improvements, and this is angiotensin, which is released during hypovolaemia. Angiotensin antagonists are used to treat many of these pathologies, and it has been shown in the obesity literature that angiotensin antagonists decrease weight, but also increase the drinking of water. Increased cellular hydration, and hence, improved mitochondrial metabolism could be one of the mechanisms for the reduction in weight seen in these studies, as well as for reducing the other pathologies, all showing metabolic dysfunction. It appears that the application of straightforward physiological regulation might be an appropriate medical approach to the prevention of hypertension, kidney disease, obesity, diabetes and cancer, and thus, to an increased life expectancy.

Aspectos gerais da avaliação pré-operatória do paciente idoso cirúrgico

As intervenções cirúrgicas em pacientes idosos têm se tornado cada vez mais frequentes, uma vez que esta população vem apresentando crescimento em número significativo nas últimas décadas e consequentemente expondo-se por mais tempo às morbidades de resolução cirúrgica. Apesar de um número importante de idosos apresentarem envelhecimento saudável e tolerarem o ato cirúrgico sem muitas intercorrências, sabe-se também que a morbi-motalidade que envolve a operação é mais frequente no indivíduo idoso e requer muito mais cuidado naquele com comorbidades. O presente trabalho se propõe a rever alguns aspectos que merecem ser mais cuidadosamente observados, porque envolvem modificações morfológicas e funcionais do organismo senescente, que guardam relação com o aumento da morbidade e da mortalidade em todo o período peri-operatório. A avaliação pré-operatória, portanto, deve pautar-se em exame criterioso de toda história clínica do paciente com vistas a estabelecer medidas de prevenção de eventos mórbidos, evitar iatrogenias, estabelecer critérios que alertem para um maior risco e desenvolver enfoque multidisciplinar.

Electrolytes in the aging

The elderly population in the United States continues to grow and is expected to double by 2050. With aging, there are degenerative changes in many organs and the kidney is no exception. After 40 years of age, there is an increase in cortical glomerulosclerosis and a decline in both glomerular filtration rate and renal plasma flow. These changes may be associated with an inability to excrete a concentrated or a dilute urine, ammonium, sodium, or potassium. Hypernatremia and hyponatremia are the most common electrolyte abnormalities found in the elderly and both are associated with a high mortality. Under normal conditions, the elderly are able to maintain water and electrolyte balance, but this may be jeopardized by an illness, a decline in cognitive ability, and with certain medications. Therefore, it is important to be aware of the potential electrolyte abnormalities in the elderly that can arise under these various conditions to prevent adverse outcomes.

Is there still a role for desmopressin in children with primary monosymptomatic nocturnal enuresis?: a focus on safety issues

It has recently became apparent that severe primary monosymptomatic nocturnal enuresis (MNE) has a worse prognosis than generally believed, and may have major consequences on the well-being of the child, thus making treatment mandatory. Desmopressin is one of the most widely prescribed medications for MNE, and in this current opinion article we discuss the safety of desmopressin in children with this condition. Following a US FDA request in December 2007 that the prescribing information for desmopressin nasal spray be updated, desmopressin spray is no longer indicated for the treatment of MNE or for use in patients at risk for hyponatraemia. Multiple reports of hyponatraemia in patients with nocturia (mainly the elderly) led to an increased awareness of the risks associated with desmopressin. While the pathogenesis of hyponatraemia in those over 65 years of age relates more to changing renal water and solute handling, we believe that in the young, overdosing and insufficient fluid restriction are usually the major causes. Hyponatraemia is most frequently reported when desmopressin is administered by nasal spray compared with the tablet formulation. This may simply reflect the fact that for more than 10 years the spray was the only available mode of administration in many countries. However, it may also reflect the higher biodisponibility and/or intraindividual variability of pharmacokinetics of the spray compared with the tablet. There are few serious adverse events reported for the melt formulation (oral lyophilisate), but as it has only recently become available on the market, it would be premature to conclude that it has a better safety profile. We believe that desmopressin in all formulations has a good safety profile in children with MNE, provided that treatment is properly prescribed and monitored; improving the training of doctors and patients in the dose-response kinetics of the drug, teaching appropriate restriction of fluid intake and by encouraging the use of desmopressin within a narrow dose range (10-20 microg spray, 120-240 microg melt and 200-400 microg tablet) when used in primary-care settings. Titrating higher doses in therapy-resistant patients should probably be carried out in a specialized enuresis centre, and only after documenting adequate morning urinary diluting capacity. In summary, the risk of hyponatraemia is exacerbated by misuse of the drug rather than an inherent danger associated with the drug, which in our opinion should be addressed with better education rather than withdrawal of a medication that has the potential to benefit children with nocturnal enuresis.

Electrolyte and salt disturbances in older people: causes, management and implications

Salt and electrolyte disturbances are commonly encountered in older patients. A sound understanding of the underlying physiological and pathological mechanisms underpinning the predisposition of older people to the common electrolyte imbalances can help clinicians minimize their considerable associated morbidity and mortality. This review focuses on the more common and clinically relevant salt and electrolyte disorders of older people. The epidemiology, causes, symptoms, diagnosis and treatment of hyponatraemia, hypernatraemia, hyperkalaemia, hypokalaemia and calcium and phosphate imbalance in old age are covered from a clinician's perspective.

Clinical assessment of dehydration in older people admitted to hospital: what are the strongest indicators?

Due to an absence of published primary data, this study explores dehydration prevalence and the change in physiological parameters frequently used to assess dehydration (fluid deficit) in older hospitalized people, as no standard measurement method exists. This observational longitudinal cohort study recruited 43 people aged 60 years or over, voluntarily admitted to a tertiary teaching hospital's Geriatric and Rehabilitation Unit (GARU). Over 40 clinical, hematological and urinary biochemical parameters employed by medical officers during dehydration assessment, identified through literature, interviews and focus group were investigated. Short-term weight changes, intra- and inter-rater repeatability of dehydration assessments were completed to assess validation and precision of the clinician's clinical dehydration assessment. Systolic blood pressure drop on standing, sternal skin turgor, tongue dryness and body mass index (BMI) were associated with hydration status; demonstrated clinically meaningful differences between groups. BMI negatively confounded the association between dehydration and systolic blood pressure drop on standing. Physical, rather than biochemical, parameters more often identified mild dehydration. The findings challenge common expectations of hematological and physiological measurement changes occurring in older people clinically assessed as dehydrated and emphasize the need to adjust for potential confounders during exploration of the associations of clinical parameters with dehydration status.

Desmopressin treatment in nocturia; an analysis of risk factors for hyponatremia

AIMS

To explore the incidence, severity, time course, and risk factors of clinically significant hyponatremia in desmopressin treatment for nocturia.

METHODS

Data from three multi-center phase III trials were pooled. Hyponatremia was categorised as borderline (134-130 mmol/L) or significant (<130 mmol/L). Risk factors were explored with logistic regression and subgroup analysis performed to explore threshold values for contra-indication.

RESULTS

In total 632 patients (344 men, 288 women) were analyzed. During dose-titration, serum sodium concentration below normal range was recorded in 95 patients (15%) and 31 patients (4.9%) experienced significant hyponatremia. The risk increased with age, lower serum sodium concentration at baseline, higher basal 24-hr urine volume per bodyweight and weight gain at time of minimum serum sodium concentration. Age was the best single predictor. Elderly patients (>or=65 years of age) with a baseline serum sodium concentration below normal range were at high risk (75%). Limiting treatment in elderly with normal basal serum sodium concentration to those below 79 years and with a 24-hr urine output below 28 ml/kg would reduce the risk from 8.1% to 3.0% at the cost of 34% fulfilling the contra-indication.

CONCLUSIONS

The majority of nocturia patients tolerate desmopressin treatment without clinically significant hyponatremia. However, the risk increases with increasing age and decreasing baseline serum sodium concentration. Treatment of nocturia in elderly patients with desmopressin should only be undertaken together with careful monitoring of the serum sodium concentration. Patients with a baseline serum sodium concentration below normal range should not be treated.

Development of Novel Anticancer Agents in Older Patients

The development of novel anticancer agents in older patients presents both challenges and unique opportunities. Intrapatient variability due to comorbid conditions and the use of multiple concomitant medications may overshadow other age-related differences in pharmacokinetics. The increasing interest in oral agents may be especially problematic in older patients who have difficulty with adherence, particularly if the oral agents are given in combination or according to complex schedules. Polypharmacy, chronic comorbid conditions, and impaired organ reserve in the elderly can lead to pharmacodynamic differences such as increased toxicity and, possibly, reduced efficacy. Hampered immune responsiveness is an important area warranting further research. The development of novel agents to treat older patients with cancer cannot be successfully accomplished without increasing the proportion of elderly patients entered into clinical trials. Furthermore, data obtained from studies in older patients may provide valuable information applicable to the development of novel agents in younger patients and to a better understanding of cancer biology and treatment in general.

Nocturia, nocturnal polyuria, and sleep quality in the elderly

Nocturia is a common symptom in the elderly, which profoundly influences general health and quality of life. One consequence of nocturia is sleep deterioration, with increased daytime sleepiness and loss of energy and activity. Accidents, e.g., fall injuries, are increased both at night and in the daytime in elderly persons with nocturia. Nocturia is caused by nocturnal polyuria, a reduced bladder capacity, or a combination of the two. Nocturnal polyuria can be caused by numerous diseases, such as diabetes insipidus, diabetes mellitus, congestive heart failure, and sleep apnoea. In the nocturnal polyuria syndrome (NPS), the 24-h diuresis is normal or only slightly increased, while there is a shift in diuresis from daytime to night. NPS is caused by a disturbance of the vasopressin system, with a lack of nocturnal increase in plasma vasopressin or, in some cases, no detectable levels of the hormone at any time of the 24-h period. The calculated prevalence of NPS is about 3% in an elderly population, with no gender difference. In NPS, there are serious sleep disturbances, partly due to the need to get up for micturition, but there is also increased difficulty in falling asleep after nocturnal awakenings and increased sleepiness in the morning. The treatment of NPS may include avoidance of excessive fluid intake, use of diuretics medication in the afternoon rather than the morning, and desmopressin orally at bedtime.

Nocturia in older people: a review of causes, consequences, assessment and management

Nocturia is common in older people and it may be bothersome for both patients and carers. It is most commonly related to bladder storage difficulties and nocturnal polyuria. The former results most frequently from an uninhibited overactive bladder. The latter occurs as a consequence of age-associated changes in the circadian rhythm of urine excretion. The management of an overactive bladder includes both behavioural and drug treatment. The management options for nocturnal polyuria include an afternoon diuretic and desmopressin, but caution is required, particularly with the latter, as it can cause significant hyponatraemia.

Nocturia and associated morbidity in a community-dwelling elderly population

OBJECTIVE

To investigate the association between nocturia and selected concomitant diseases and medications in a community-dwelling elderly population.

SUBJECTS AND METHODS

Data were obtained with a validated questionnaire mailed to all inhabitants aged >or= 65 years in Tierp, Sweden. Descriptive statistics on age, gender, concomitant diseases and medications were calculated for non-nocturics (subjects reporting a mean of < 1 void/night), intermediate (reporting a mean of 1-2 voids/night) and nocturics (reporting a mean of >or= 2 voids/night). Correlations between the number of nocturnal voids/week and concomitant diseases/medications were investigated with logistic regression, controlling for age and gender.

RESULTS

Of the 4264 questionnaires sent, 67% (2866) were returned, of which 73% (2081) were fully evaluable on nocturia and incorporated in the analysis. Of these, 62% reported >or= 1 void/night and 29%>or= 2 voids/night. The median (range) age of the respondents was 74 (65-99) years. The prevalence of nocturia increased with age and men reported more nocturia than women. The nocturic group had the highest percentage of reported disease and medication on each question. In the logistic regression, controlling for age and gender, there was no significant correlation between the number of nocturnal voids and hypertension, angina pectoris or diabetes mellitus, nor with treatment of these diseases. Neither was there any correlation for congestive heart failure, snoring, use of diuretics or hypnotics. There were highly statistically significant correlations (P < 0.001) between the increase in number of nocturnal voids and incontinence, daytime urge and nocturnal thirst. The increase in number of nocturnal voids was negatively correlated with good sleep and with feeling in good health (P < 0.001).

CONCLUSION

There was no correlation between the number of nocturnal voids and a known and treated hypertension, angina pectoris, congestive heart failure or diabetes mellitus. The number of nocturnal voids was highly correlated with urge and incontinence.

Maintaining oral hydration in older adults: a systematic review

Dehydration is the most common fluid and electrolyte imbalance in older adults. The objectives were to identify the factors that increase the risk of dehydration in older adults, how best to assess the risk and manage oral fluid intake. Data sources included Medline, CINAHL, Cochrane Library, Embase and Current Contents, which were searched until February 2002. Randomized controlled trials for management of adequate fluid intake were undertaken. Cohort and case control studies were used for the identification of risk factors for dehydration. Studies of assessment tools for the identification of dehydration were also considered. Results show that there is no clear determination of the risk factors for dehydration and decreased fluid intake. The recommended daily intake of fluids should be not less than 1600 mL/24 h in order to ensure adequate hydration. A fluid intake sheet and urine specific gravity might be the best methods of monitoring daily fluid intake. Regular presentation of fluids to bedridden older adults can maintain adequate hydration status. In conclusion, more research is required to determine the optimum method of maintaining adequate oral hydration in older adults.

Desmopressin in elderly patients with nocturia: short-term safety and effects on urine output, sleep and voiding patterns

OBJECTIVE

To investigate the short-term safety of desmopressin in elderly patients with nocturia, with special focus on the risk of hyponatraemia, and to assess the short-term effects on urine output, sleep and voiding patterns.

PATIENTS AND METHODS

Patients (72) were recruited from a study using frequency-volume charts, which in turn was preceded by a questionnaire study. Each patient took one 0.2 mg desmopressin tablet at bedtime for three consecutive nights and kept a frequency-volume chart. Serum sodium was assessed in the morning after the first and the third dose. Patients with a mean serum sodium level during treatment deviating more than five units from baseline were considered sensitive to change in serum sodium. Potential predictors for sodium sensitivity and response were investigated with logistic and multiple regression.

RESULTS

All 72 enrolled patients completed the trial; no serious adverse events occurred and no adverse events of severe intensity were recorded. Six patients were sensitive to change in serum sodium. The risk (odds ratio, 95% confidence interval) increased with increasing age (1.3, 1.1-1.6), concomitant cardiac disease (10.0, 0.9-105.8) and increasing baseline 24-h urine output (1.2, 1.0-1.5). Patients sensitive to change in serum sodium were pharmacological responders and desmopressin had a greater effect on their 24-h diuresis, indicating that the drug effect was not limited to the night only.

CONCLUSION

Desmopressin was well tolerated in elderly patients with nocturia, but the results suggest that serum sodium should be measured before and after a few days of treatment.

Gender influence on vasoactive hormones at rest and during a 70 degrees head-up tilt in healthy humans

To evaluate the influence of age and gender on the neuroendocrine control of blood pressure in normal subjects, a 13-min 70 degrees head-up tilt (HUT) was applied after 3 h of recumbency to 109 healthy men and women aged 23-50 yr (age group I) and 51-77 yr (age group II). We found that age and gender had a significant influence on plasma norepinephrine (PNE) concentration at baseline and in the upright position. PNE was significantly higher in older men compared with the younger men and women of both age groups, suggesting a divergent age-related activation of the sympathetic nervous system between genders at baseline as well as during a sustained orthostatic challenge. There was no significant influence of age or gender on plasma epinephrine at baseline or during HUT. Plasma renin activity was significantly higher at baseline as well as in the upright position during HUT in elderly men than in women. Age or gender had no influence on plasma vasopressin (PAVP), and, regardless of age, nonhypotensive HUT induced an extremely modest increase in PAVP. The syncopal subjects displayed a hormonal pattern associating increased PNE and a surge in plasma epinephrine and PAVP minutes before syncope during HUT. The orthostatic intolerance appears not to be a feature of healthy aging per se. In healthy subjects, both age and gender modulate markedly the cardiovascular and neuroendocrine responses to an orthostatic challenge and must be taken into consideration, particularly when catecholamine responses are studied.

Effect of age on renal functional and orthostatic vascular response in healthy men

1. Few studies have been reported concerning the effect of ageing on renal functional and vascular responses to various stresses during ordinary life. In the present study, we examined the effect of age on changes in renal sodium handling and renal vascular resistance (RVR) in response to standing from a supine position in subjects with normal renal function. 2. We selected 43 healthy males in the second through to the seventh decade of life and gave them a constant dietary sodium intake before the study period. Renal function was estimated by standard clearance methods with the subject in a state of euvolaemia. 3. The mean daily urinary excretion of sodium was 236 +/- 22 mEq. Standing from a supine position was associated with significant decreases (P < 0.0001) in creatinine clearance (from 125 +/- 18 to 117 +/- 19 mL/min per 1.73 m2), sodium excretion (from 178 +/- 29 to 97 +/- 23 microEq/min) and fractional excretion of sodium (from 1.02 +/- 0.19 to 0.60 +/- 0.13%). A significant increase (P < 0.0001) in the RVR index (from 0.11 +/- 0.03 to 0.14 +/- 0.04 units) was noted. Univariate analysis indicated that while the change in RVR associated with standing was significantly diminished (P < 0.05) in older subjects, orthostatic changes in other parameters associated with standing were minimally influenced by age. 4. In conclusion, although the renal vascular response is impaired in advanced age, the renal functional response to orthostasis is otherwise maintained in healthy elderly subjects under conditions of normal sodium intake and clinical euvolaemia.

Nocturnal polyuria in older people: pathophysiology and clinical implications

OBJECTIVES

To review the physiological changes of aging which affect the systems involved in urine formation and to consider how these changes interact with changes in bladder function, thereby leading to the onset of nocturnal polyuria with associated urinary frequency, nocturia, and incontinence. Based on this information, data are presented on the effectiveness of pharmacological interventions which reduce the rate of urine formation and, thus, can be of benefit in reducing symptoms, especially during the nighttime.

METHODS

Peer-reviewed journal articles were identified by MEDLINE Search and by review of the literature.

CONCLUSIONS

As a consequence of age-associated diminished renal concentrating capacity, diminished sodium conserving ability, loss of the circadian rhythm of antidiuretic hormone secretion, decreased secretion of renin-angiotensin-aldosterone, and increased secretion of atrial natriuretic hormone, there is an age-related alteration in the circadian rhythm of water excretion leading to increased nighttime urine production in older people. The interaction of nocturnal polyuria with age-related diminution in functional bladder volume and detrusor instability results in the symptoms of urinary frequency, nocturia and, in some persons, incontinence. The additional impact of Alzheimer's disease on these physiological and aging changes, as well as on a diminished perception of bladder fullness, leads to an even greater risk of urinary incontinence in these patients. Treatment of nocturnal polyuria with the antidiuretic hormone analog, DDAVP (desmopressin), can result in decreased nocturnal urine production with improvement in symptoms of frequency, nocturia, and incontinence.