Urinary Retention in Older Adults with Hyponatraemia admitted to Internal Medical and acute Geriatric wards

Urinary Retention in Older Adults with Hyponatraemia admitted to Internal Medical and acute Geriatric wards | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Urinary Retention in Older Adults with Hyponatraemia admitted to Internal Medical and acute Geriatric wards Dvorah Sara Shapiro, Raphael Ellis, Husam Mouhtaseb, Moshe Sonnenblick, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4896469/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Hyponatraemia and urinary retention are common medical problems. Whilst associations between the two are documented, research has not clearly highlighted the prevalence of urinary retention in hyponatraemic patients. Objectives Determining the prevalence of urinary retention in hyponatraemic patients and assessing whether urinary catheter insertion itself affects the correction rate. Methods A prospective, single centre, observational study including patients hospitalised in internal medicine and geriatric wards. A total of 199 patients were investigated: 100 with hyponatraemia ≤129 mEq/L, of these, 70 had severe hyponatraemia ≤125 mEq/L and 99 normonatraemic controls. The incidence of urinary retention was checked in all groups. Hyponatraemic patients underwent complete assessment for the cause of hyponatraemia and sodium levels were followed up for 48 hours. Results: There was a marked increase in the incidence of urinary retention in hyponatremic patients as compared to those with normal sodium levels (41% vs 21% p=0.004). When comparing to those with severe hyponatraemia, a slightly greater difference was found (44% vs 21% p=0.001). When comparing the hyponatraemic patients with and without urinary retention, there was no difference in sodium correction rate between the two groups. Patients with polyuria secondary to post obstructive diuresis had a more rapid sodium correction (9.2±6.8mEq/L vs 5.8±4.8mEq/L (p=0.05)) Conclusions: There is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. Post obstructive diuresis following catheter insertion is a predictor of rapid sodium correction. We recommend a routine bladder scan for all patients with hyponatraemia. Hyponatraemia urinary retention older adults Key Points There is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. Post obstructive diuresis following catheter insertion is a predictor of rapid sodium correction. We recommend a routine bladder scan for all patients with hyponatraemia. Introduction Hyponatraemia and urinary retention are common in acute medical and geriatric wards. Several studies have shown an association between these [ 1 , 2 , 3 , 4 ] but none have evaluated the prevalence of urinary retention in patients with hyponatraemia. In a prospective controlled study [ 5 ] the reverse association was evaluated, analysing the incidence of hyponatremia in patients with acute urinary tract obstruction (aUTO). The incidence of hyponatraemia was similar in patients with aUTO compared with the control group, independent of age, baseline co-morbidities or cause of admission. However, the mean sodium level was lower, and the incidence of severe hyponatraemia was significantly higher, in patients with aUTO as compared with controls. Notably, relief of aUTO led to a significant and rapid improvement in serum sodium level. Similarly, a previous case series on a geriatric ward described six older patients with co-existing hyponatraemia and urinary retention. In all these patients, serum sodium levels normalised and remained stable following foley catheter insertion and water restriction. Most of the patients underwent extensive diagnostic workups during their hospitalisation and no specific cause of hyponatraemia other than urinary retention was found [ 4 ]. Other anecdotal reports which are summarised in two recent studies have highlighted hyponatraemia in patients with (aUTO), which subsides rapidly with relief of the obstruction [ 1 , 5 ]. The primary aim of this study was to determine the prevalence of urinary retention in patients with hyponatremia; we compared the prevalence of urinary retention in patients with severe (< 126 mEq/L) and moderate (126–129 mEq/L) hyponatremia to patients with normal sodium levels. The secondary aim was to assess whether urinary catheter insertion itself affected the correction rate. Methods A prospective, observational, single-centre, study conducted in Shaare Zedek Medical Center (SZMC), Jerusalem, Israel, a university-affiliated 1,000-bed general community hospital. During the study period, general medical patients aged 65 years and older who had a serum sodium level of 129 mEq/L or less were investigated. Patients with haemodialysis, nephrostomy, ileal conduit or permanent catheter were excluded. A bladder scan was performed on all patients. Those with urinary retention (defined as residual volume > 400 ml) had a urinary catheter inserted. Demographic and clinical characteristics including clinical presentation and drug history were collected. All patients underwent a complete physical examination and an assessment of their volaemic status. The laboratory work up included a complete blood count, biochemistry with serum osmolarity, urinary sodium and osmolarity. Thyroid-stimulating hormone (TSH) levels were obtained in most patients and cortisol levels taken where there was clinical suspicion of adrenal insufficiency. Most patients underwent a chest X-ray. Other radiological tests were performed as considered necessary by the attending physician. Syndrome of inappropriate ADH secretion (SIADH) was defined clinically [ 6 ]. Sodium level was repeated during the following 48 hours. We collected a control group of hospitalised 65 years and older patients in internal medical and geriatric wards with normal sodium levels to evaluate the incidence of urinary retention in normonatraemic hospitalised patients. The study was approved by the Ethics Committee of SZMC. Written consent was not obtained from individual patients, as the study was based on data collected for routine care. Results One hundred and ninety-nine patients were investigated. One hundred with hyponatraemia less than 129 mEq/L, of these, 70 patients had severe hyponatraemia ≤ 125 mEq/L. There were 99 normonatraemic controls. There was a marked increase in the incidence of urinary retention in hyponatremic patients as compared to those with normal sodium levels (41% vs 21% p = 0.004). In the 70 patients with severe hyponatraemia the incidence of urinary retention was even higher 44% (p = 0.004). There was no significant difference in sex or age of the patients between the study and control group as can be seen in Table 1 . We note the slightly lower prevalence of men in the hyponatraemia group (33% Vs 45%) and despite this, the higher prevalence of urinary retention. In the 41 patients with hyponatraemia and urinary retention, the retention volume was 715 ± 367ml which was similar to the volume in 21 patients with urinary retention in the normonatraemic group 670 ± 246ml (p = 0.61). There was no correlation between retention volume and sodium level (r=-0.063, p = 0.63). Table 2 compares hyponatraemic patients with and without urinary retention. These sub-groups were similar in age, gender, and co-morbidity burden. Similarly, there was no difference in use of drugs commonly causing hyponatraemia, volume status or blood test results. Mean basal sodium levels were similar in both groups 123 mEq/L vs 121 mEq/L (p = 0.178). Of the 41 patients with hyponatraemia and urinary retention, 19 (46.3%) had SIADH. Of note, there was a very small group of six patients who did not receive any specific treatment for hyponatraemia. Four of these had urinary retention which was relieved with a catheter. The mean sodium improvement in the four patients with urinary retention was 10.8 ± 6.1 mEq/L, much above the overall average of 6.4 ± 5.4 mEq/L (p = 0.17). Regarding factors associated with correction of sodium levels, other interesting data emerged from our study group regarding volume status and polyuria. The volume status of patients had a minor effect on the rate of correction: Hypervolaemic patients had a slightly slower correction rate than euvolaemic and hypovolemic patients (hypervolemic 4.3 ± 3.1 mEq/L, euvolemic 7.1 ± 6.0 mEq/L, hypovolemic 7.2 ± 5.5 mEq/L (p = 0.022)). Patients with polyuria secondary to post obstructive diuresis did have more rapid sodium correction; 11 patients with polyuria had a sodium correction rate of 9.2 ± 6.8 mEq/L compared to 24 patients without polyuria who had a correction rate of 5.8 ± 4.8 mEq/L (p = 0.05). Discussion Hyponatremia is a common medical problem and whilst previous research has shown an association with urinary retention, the prevalence of urinary retention in patients with hyponatremia has not been described. This prevalence is important clinical information when evaluating a patient with hyponatremia. Indeed, we found a significantly raised prevalence of urinary retention amongst patients with hyponatremia. Interestingly, our control group of similar hospitalised patients had a markedly high prevalence of urinary retention of 21%. This high prevalence amongst unwell, bed restricted inpatients is worthy of investigation in future research. Regarding our secondary aim of whether catheter insertion itself corrects hyponatraemia, our previous study [ 5 ] showed that in a small group of seven severely hyponatraemic patients, urinary catheter insertion led to a significantly increased sodium correction rate (9.6 ± 3mEq/L/48hours). Our current study did not demonstrate this difference. Notably, in patients with polyuria after catheter insertion, there was a significant sodium increase. Thus, polyuria could have been the cause of the improvement seen in the above study [ 5 ]. Consistent with this finding, a recent case series of three patients with severe hyponatraemia and urinary retention all had polyuria and a rapid sodium correction due to free water clearance and interventions were necessary to prevent the rapid increase of plasma sodium [ 1 ]. In our study, we could not isolate catheter insertion as an independent factor for correcting sodium level because everyone received standard hyponatremia treatment together with catheter insertion when needed. However, in a very small group of four patients for whom the only treatment was catheter insertion, the sodium correction was above average (10.8 mEq/L). This may be an important observation because these patients improved at an above average rate despite receiving no other treatment. Future research would investigate catheter insertion as the sole treatment for asymptomatic patients with hyponatraemia and urinary retention. Concerning the main finding of increased prevalence of urinary retention in patients with hyponatraemia, we summarise several theories to explain the pathophysiology: Hyponatremia in urinary retention could result from ADH secretion secondary to the pain of bladder distension in aUTO. Indeed, the prevalence of patients with SIADH in this group is 19 of the 41 (46%). There was no correlation between the volume of retention in patients with urinary retention to sodium level. An alternative explanation may be “functional aUTO” where the hyponatraemia causes an altered conscious state in which the patient refrains from passing urine and thus develops urinary retention. Similarly, hypervolaemic hyponatraemic patients receiving diuretic therapy may find that the large urine volume and frequency make it impossible to mobilise to the lavatory and thus withhold urine output. Additionally, patients experiencing decreased urinary output may drink more believing it will encourage urination and dilutional hyponatraemia. This itself may exacerbate hyponatraemia, as the therapeutic response would be to restrict water [ 3 ]. Further research to investigate the causes of urinary retention in hyponatraemia should be conducted. For example, the ADH theory could be tested by checking ADH levels in patients with different retention volumes. This study was impressive for its large number of patients in the study and control groups. There was detailed clinical and laboratory data available for most patients in the study group. However, this was a descriptive study which did not allow for assessing the effect of interventions (for example assessing catheter insertion as a sole treatment) in a significant way. In summary, there is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. We recommend a routine bladder scan for all patients presenting with hyponatraemia. A significant predictor of rapid sodium correction is polyuria following urinary catheter insertion. On behalf of all authors, the corresponding author states that there is no conflict of interest. Table 1 The characteristics of patients according to sodium level Na < 126 mEq/L (n = 70) Na126-129 mEq/L (n = 30) Na < 130 mEq/L (n = 100) Na ≥ 135 mEq/L (n = 99) P value* Age (year), M (SD) 84.4 (8.5) 84.9 (7.9) 84.6 (8.3) 84 (8.4) .618 Sex (male) (%) 25 (36) 8 (27) 33 (33) 45(45) .098 Na (mEq/L), M (SD) 119.8 (4.4) 127.1 (1.2) 122 (5.1) 139.1 (2.7) < 0.0005 Urinary retention (%),(mean volume ml) 31 (44) (705) 10 (33) (749) 41 (41) (715) 21 (21) (670) .004 * Between research group (Na < 130) and compare group (Na ≥ 135 mEq/L) Table 2 –Hyponatraemic patients with and without urinary retention Urinary retention Yes (n = 41) No (n = 59) P value Age(year), M (SD) 84.5 (8.5) 84.7 (8.2) .900 Sex, (male, N (%)) 14 (34) 19 (32) 1.000 Comorbidities, N (%) Diabetes mellitus 13 (32) 18 (31) 1.000 Hypertension 30 (73) 46 (78) .753 Congestive heart failure 11 (27) 19 (32) .723 Cerebrovascular accident 4 (10) 9 (15) .616 Chronic kidney disease 9 (22) 12 (20) 1.000 Malignancy 4 (10) 9 (15) .616 Hospitalization reason, N (%) .945 Hyponatremia 8 (20) 14 (24) Fall 5 (12) 7 (12) Cardiovascular disease 6 (15) 11 (19) Infection 11 (27) 14 (24) Other 11 (27) 13 (22) Medication, N (%) Thiazide 2 (5) 4 (7) 1.000 SSRI 5 (12) 5 (9) .786 Opioids 1 (2) 4 (7) .608 Volaemic status, N (%) .215 Euvolaemic 21 (51) 25 (42) Hypervolaemic 12 (29) 13 (22) Hypovolaemic 8 (20) 21 (36) Admission Na (mEq/L), Mean (SD) 121 (5.56) 123 (4.95) .178 Admission NA ≤ 125, N(%) 30 (73) 36 (61) .295 NA delta (mEq/L) (48 hours), M (SD) 6.8 (5.4) 6.1 (5.4) .518 Volume retention (ml), M (SD) 715(367) 151(116) < 0.005 Laboratory, M (SD) Bun (mg/dL) 30.7 (22.9) 30.7 (24) .994 Creatinine (mg/dL) 1.4 (1.4) 1.3 (1.2) .762 Albumin (gr/dL) 3.3 (0.5) 3.2 (0.7) .105 Potassium (mEq/L) 4.2 (0.8) 4.3 (0.7) .549 Hemoglobin (g/dL) 11.3 (1.8) 10.9 (2.1) .358 WBC (10ᶺ3/uL) 11.2 (4.6) 11.8 (14.8) .820 Platelets (10ᶺ3/uL) 288.5 (99.8) 232.5 (89.7) .004 TSH (mIU/L) 3.1 (4.5) 2.99 (3.5) .952 Exitus, N (%) 2 (5) 8 (14) .278 Treatment, N (%) Saline 3% 13 (32) 18 (31) 1.000 Water restriction 7 (17) 14 (24) .580 Furosemide 13 (32) 20 (34) .990 Drug withdrawal 9 (22) 14 (24) 1.000 NaCl 0.9% 30 (73) 41 (70) .861 References van der Bilt F, Alsma J (2023) Hyponatraemia caused by transient syndrome of inappropriate antidiuresis to urinary retention. Intern Med J 53:285–288 Moskowitz DW (1992) Functional obstructive uropathy: a significant factor in the hyponatremia of psychogenic polydipsia? J Urol 147:1611–1613 Pyle R, Scott M, Bartholomew J et al (2011) Accidental polydipsia and hyponatremia from diphenhydramine urinary retention. Am J Med 124:e5–6 Galperin I, Friedmann R, Feldman H et al (2007) Urinary retention: a cause of hyponatremia? Gerontology 53:121–124 Shapiro DS, Alexandrovich I, Sonnenblick M et al (2022) Prospective determination of the incidence and severity of hyponatraemia in older hospitalised patients with acute urinary tract obstruction. Age Ageing 51. 10.1093/ageing/afab234 Syndrome of inappropriate antidiuretic hormone - Symptoms, diagnosis and treatment | BMJ Best Practice US Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-4896469","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":339597923,"identity":"371624f7-d25e-43fd-83bd-e81f4262c52d","order_by":0,"name":"Dvorah Sara Shapiro","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIie3PvarCMBTA8XPI6sdqwYcQfJy7GApucXHpoCFQqEsfwHKlvoJdOrcE2qXgWtBBcL1D3To43Bhd23q3C+YP+RjygxwAk+k/ljyPGQAKAEddCRF/IcWD4NtEhZ7e28mgtLOqBr4YfrtedQvXX8ONIrUTNxKrnNuBD3I5OqduEMQ520oU6BenRjIpiin0IKGipC7pxxkTihD02gnegdO9JruM7TtJ7k9JDwg9aCJW7NBFrNyzyXgiaaRmwW2WsEiRtG2WgSQSfxxOw9PmCtWKs/Ao00vtNJPX99Qa6ZvUe9Lx/tWT8Pcem0wm00f1C4F9YLbciRztAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0001-5765-8645","institution":"Shaare Zedek Medical Center","correspondingAuthor":true,"prefix":"","firstName":"Dvorah","middleName":"Sara","lastName":"Shapiro","suffix":""},{"id":339597924,"identity":"105ae2ed-2392-4143-9d75-8ccda0414924","order_by":1,"name":"Raphael Ellis","email":"","orcid":"","institution":"Shaare Zedek Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Raphael","middleName":"","lastName":"Ellis","suffix":""},{"id":339597925,"identity":"4da85fed-a0c8-4274-b035-53cc41f92af7","order_by":2,"name":"Husam Mouhtaseb","email":"","orcid":"","institution":"Shaare Zedek Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Husam","middleName":"","lastName":"Mouhtaseb","suffix":""},{"id":339597926,"identity":"6fd2165c-a950-4a46-9e3d-88e58644d3d1","order_by":3,"name":"Moshe Sonnenblick","email":"","orcid":"","institution":"Shaare Zedek Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Moshe","middleName":"","lastName":"Sonnenblick","suffix":""},{"id":339597927,"identity":"85ed96d6-a393-4b0b-a218-57d301163940","order_by":4,"name":"Gabriel Munter","email":"","orcid":"","institution":"Shaare Zedek Medical Center","correspondingAuthor":false,"prefix":"","firstName":"Gabriel","middleName":"","lastName":"Munter","suffix":""}],"badges":[],"createdAt":"2024-08-11 19:17:50","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4896469/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4896469/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":68351240,"identity":"ddd3ddc1-3558-40d7-b182-c0a9dbc47edf","added_by":"auto","created_at":"2024-11-06 10:39:37","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":356023,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4896469/v1/fd983a66-c640-4994-bbbe-786948dbc6c6.pdf"}],"financialInterests":"","formattedTitle":"Urinary Retention in Older Adults with Hyponatraemia admitted to Internal Medical and acute Geriatric wards","fulltext":[{"header":"Key Points","content":"\u003cul\u003e\n \u003cli\u003eThere is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. \u0026nbsp;\u0026nbsp;\u003c/li\u003e\n \u003cli\u003ePost obstructive diuresis following catheter insertion is a predictor of rapid sodium correction. \u0026nbsp;\u003c/li\u003e\n \u003cli\u003eWe recommend a routine bladder scan for all patients with hyponatraemia.\u003c/li\u003e\n\u003c/ul\u003e"},{"header":"Introduction","content":"\u003cp\u003eHyponatraemia and urinary retention are common in acute medical and geriatric wards. Several studies have shown an association between these [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] but none have evaluated the prevalence of urinary retention in patients with hyponatraemia.\u003c/p\u003e \u003cp\u003eIn a prospective controlled study [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] the reverse association was evaluated, analysing the incidence of hyponatremia in patients with acute urinary tract obstruction (aUTO). The incidence of hyponatraemia was similar in patients with aUTO compared with the control group, independent of age, baseline co-morbidities or cause of admission. However, the mean sodium level was lower, and the incidence of severe hyponatraemia was significantly higher, in patients with aUTO as compared with controls. Notably, relief of aUTO led to a significant and rapid improvement in serum sodium level.\u003c/p\u003e \u003cp\u003eSimilarly, a previous case series on a geriatric ward described six older patients with co-existing hyponatraemia and urinary retention. In all these patients, serum sodium levels normalised and remained stable following foley catheter insertion and water restriction. Most of the patients underwent extensive diagnostic workups during their hospitalisation and no specific cause of hyponatraemia other than urinary retention was found [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Other anecdotal reports which are summarised in two recent studies have highlighted hyponatraemia in patients with (aUTO), which subsides rapidly with relief of the obstruction [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eThe primary aim of this study was to determine the prevalence of urinary retention in patients with hyponatremia; we compared the prevalence of urinary retention in patients with severe (\u0026lt;\u0026thinsp;126 mEq/L) and moderate (126\u0026ndash;129 mEq/L) hyponatremia to patients with normal sodium levels.\u003c/p\u003e \u003cp\u003eThe secondary aim was to assess whether urinary catheter insertion itself affected the correction rate.\u003c/p\u003e"},{"header":"Methods","content":"\u003cp\u003eA prospective, observational, single-centre, study conducted in Shaare Zedek Medical Center (SZMC), Jerusalem, Israel, a university-affiliated 1,000-bed general community hospital. During the study period, general medical patients aged 65 years and older who had a serum sodium level of 129 mEq/L or less were investigated. Patients with haemodialysis, nephrostomy, ileal conduit or permanent catheter were excluded.\u003c/p\u003e \u003cp\u003eA bladder scan was performed on all patients. Those with urinary retention (defined as residual volume\u0026thinsp;\u0026gt;\u0026thinsp;400 ml) had a urinary catheter inserted. Demographic and clinical characteristics including clinical presentation and drug history were collected. All patients underwent a complete physical examination and an assessment of their volaemic status. The laboratory work up included a complete blood count, biochemistry with serum osmolarity, urinary sodium and osmolarity. Thyroid-stimulating hormone (TSH) levels were obtained in most patients and cortisol levels taken where there was clinical suspicion of adrenal insufficiency. Most patients underwent a chest X-ray. Other radiological tests were performed as considered necessary by the attending physician. Syndrome of inappropriate ADH secretion (SIADH) was defined clinically [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Sodium level was repeated during the following 48 hours.\u003c/p\u003e \u003cp\u003eWe collected a control group of hospitalised 65 years and older patients in internal medical and geriatric wards with normal sodium levels to evaluate the incidence of urinary retention in normonatraemic hospitalised patients.\u003c/p\u003e \u003cp\u003e The study was approved by the Ethics Committee of SZMC. Written consent was not obtained from individual patients, as the study was based on data collected for routine care.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eOne hundred and ninety-nine patients were investigated. One hundred with hyponatraemia less than 129 mEq/L, of these, 70 patients had severe hyponatraemia\u0026thinsp;\u0026le;\u0026thinsp;125 mEq/L. There were 99 normonatraemic controls.\u003c/p\u003e \u003cp\u003eThere was a marked increase in the incidence of urinary retention in hyponatremic patients as compared to those with normal sodium levels (41% vs 21% p\u0026thinsp;=\u0026thinsp;0.004). In the 70 patients with severe hyponatraemia the incidence of urinary retention was even higher 44% (p\u0026thinsp;=\u0026thinsp;0.004). There was no significant difference in sex or age of the patients between the study and control group as can be seen in Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. We note the slightly lower prevalence of men in the hyponatraemia group (33% Vs 45%) and despite this, the higher prevalence of urinary retention.\u003c/p\u003e \u003cp\u003eIn the 41 patients with hyponatraemia and urinary retention, the retention volume was 715\u0026thinsp;\u0026plusmn;\u0026thinsp;367ml which was similar to the volume in 21 patients with urinary retention in the normonatraemic group 670\u0026thinsp;\u0026plusmn;\u0026thinsp;246ml (p\u0026thinsp;=\u0026thinsp;0.61). There was no correlation between retention volume and sodium level (r=-0.063, p\u0026thinsp;=\u0026thinsp;0.63).\u003c/p\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e compares hyponatraemic patients with and without urinary retention. These sub-groups were similar in age, gender, and co-morbidity burden. Similarly, there was no difference in use of drugs commonly causing hyponatraemia, volume status or blood test results. Mean basal sodium levels were similar in both groups 123 mEq/L vs 121 mEq/L (p\u0026thinsp;=\u0026thinsp;0.178). Of the 41 patients with hyponatraemia and urinary retention, 19 (46.3%) had SIADH.\u003c/p\u003e \u003cp\u003eOf note, there was a very small group of six patients who did not receive any specific treatment for hyponatraemia. Four of these had urinary retention which was relieved with a catheter. The mean sodium improvement in the four patients with urinary retention was 10.8\u0026thinsp;\u0026plusmn;\u0026thinsp;6.1 mEq/L, much above the overall average of 6.4\u0026thinsp;\u0026plusmn;\u0026thinsp;5.4 mEq/L (p\u0026thinsp;=\u0026thinsp;0.17).\u003c/p\u003e \u003cp\u003eRegarding factors associated with correction of sodium levels, other interesting data emerged from our study group regarding volume status and polyuria.\u003c/p\u003e \u003cp\u003eThe volume status of patients had a minor effect on the rate of correction: Hypervolaemic patients had a slightly slower correction rate than euvolaemic and hypovolemic patients (hypervolemic 4.3\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1 mEq/L, euvolemic 7.1\u0026thinsp;\u0026plusmn;\u0026thinsp;6.0 mEq/L, hypovolemic 7.2\u0026thinsp;\u0026plusmn;\u0026thinsp;5.5 mEq/L (p\u0026thinsp;=\u0026thinsp;0.022)).\u003c/p\u003e \u003cp\u003ePatients with polyuria secondary to post obstructive diuresis did have more rapid sodium correction; 11 patients with polyuria had a sodium correction rate of 9.2\u0026thinsp;\u0026plusmn;\u0026thinsp;6.8 mEq/L compared to 24 patients without polyuria who had a correction rate of 5.8\u0026thinsp;\u0026plusmn;\u0026thinsp;4.8 mEq/L (p\u0026thinsp;=\u0026thinsp;0.05).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eHyponatremia is a common medical problem and whilst previous research has shown an association with urinary retention, the prevalence of urinary retention in patients with hyponatremia has not been described. This prevalence is important clinical information when evaluating a patient with hyponatremia. Indeed, we found a significantly raised prevalence of urinary retention amongst patients with hyponatremia.\u003c/p\u003e \u003cp\u003eInterestingly, our control group of similar hospitalised patients had a markedly high prevalence of urinary retention of 21%. This high prevalence amongst unwell, bed restricted inpatients is worthy of investigation in future research.\u003c/p\u003e \u003cp\u003eRegarding our secondary aim of whether catheter insertion itself corrects hyponatraemia, our previous study [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] showed that in a small group of seven severely hyponatraemic patients, urinary catheter insertion led to a significantly increased sodium correction rate (9.6\u0026thinsp;\u0026plusmn;\u0026thinsp;3mEq/L/48hours). Our current study did not demonstrate this difference. Notably, in patients with polyuria after catheter insertion, there was a significant sodium increase. Thus, polyuria could have been the cause of the improvement seen in the above study [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Consistent with this finding, a recent case series of three patients with severe hyponatraemia and urinary retention all had polyuria and a rapid sodium correction due to free water clearance and interventions were necessary to prevent the rapid increase of plasma sodium [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn our study, we could not isolate catheter insertion as an independent factor for correcting sodium level because everyone received standard hyponatremia treatment together with catheter insertion when needed. However, in a very small group of four patients for whom the only treatment was catheter insertion, the sodium correction was above average (10.8 mEq/L). This may be an important observation because these patients improved at an above average rate despite receiving no other treatment. Future research would investigate catheter insertion as the sole treatment for asymptomatic patients with hyponatraemia and urinary retention.\u003c/p\u003e \u003cp\u003eConcerning the main finding of increased prevalence of urinary retention in patients with hyponatraemia, we summarise several theories to explain the pathophysiology:\u003c/p\u003e \u003cp\u003eHyponatremia in urinary retention could result from ADH secretion secondary to the pain of bladder distension in aUTO. Indeed, the prevalence of patients with SIADH in this group is 19 of the 41 (46%). There was no correlation between the volume of retention in patients with urinary retention to sodium level.\u003c/p\u003e \u003cp\u003eAn alternative explanation may be \u0026ldquo;functional aUTO\u0026rdquo; where the hyponatraemia causes an altered conscious state in which the patient refrains from passing urine and thus develops urinary retention. Similarly, hypervolaemic hyponatraemic patients receiving diuretic therapy may find that the large urine volume and frequency make it impossible to mobilise to the lavatory and thus withhold urine output.\u003c/p\u003e \u003cp\u003eAdditionally, patients experiencing decreased urinary output may drink more believing it will encourage urination and dilutional hyponatraemia. This itself may exacerbate hyponatraemia, as the therapeutic response would be to restrict water [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurther research to investigate the causes of urinary retention in hyponatraemia should be conducted. For example, the ADH theory could be tested by checking ADH levels in patients with different retention volumes.\u003c/p\u003e \u003cp\u003eThis study was impressive for its large number of patients in the study and control groups. There was detailed clinical and laboratory data available for most patients in the study group. However, this was a descriptive study which did not allow for assessing the effect of interventions (for example assessing catheter insertion as a sole treatment) in a significant way.\u003c/p\u003e \u003cp\u003eIn summary, there is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. We recommend a routine bladder scan for all patients presenting with hyponatraemia. A significant predictor of rapid sodium correction is polyuria following urinary catheter insertion.\u003c/p\u003e \u003cp\u003eOn behalf of all authors, the corresponding author states that there is no conflict of interest.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eThe characteristics of patients according to sodium level\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"6\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNa\u0026thinsp;\u0026lt;\u0026thinsp;126 mEq/L (n\u0026thinsp;=\u0026thinsp;70)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNa126-129 mEq/L (n\u0026thinsp;=\u0026thinsp;30)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eNa\u0026thinsp;\u0026lt;\u0026thinsp;130 mEq/L (n\u0026thinsp;=\u0026thinsp;100)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eNa\u0026thinsp;\u0026ge;\u0026thinsp;135 mEq/L (n\u0026thinsp;=\u0026thinsp;99)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eP value*\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (year), M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e84.4 (8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e84.9 (7.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84.6 (8.3)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e84 (8.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.618\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex (male) (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e25 (36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33 (33)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e45(45)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.098\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNa (mEq/L), M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e119.8 (4.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e127.1 (1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e122 (5.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e139.1 (2.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.0005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrinary retention (%),(mean volume ml)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e31 (44) (705)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10 (33) (749)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e41 (41) (715)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e21 (21) (670)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"6\"\u003e* Between research group (Na\u0026thinsp;\u0026lt;\u0026thinsp;130) and compare group (Na\u0026thinsp;\u0026ge;\u0026thinsp;135 mEq/L)\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003e\u0026ndash;Hyponatraemic patients with and without urinary retention\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eUrinary retention\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eYes (n\u0026thinsp;=\u0026thinsp;41)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eNo (n\u0026thinsp;=\u0026thinsp;59)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eP value\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge(year), M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e84.5 (8.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e84.7 (8.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.900\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex, (male, N (%))\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e14 (34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eComorbidities, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDiabetes mellitus\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypertension\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e46 (78)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.753\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCongestive heart failure\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e19 (32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.723\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCerebrovascular accident\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.616\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChronic kidney disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12 (20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMalignancy\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4 (10)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9 (15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.616\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHospitalization reason,\u003c/p\u003e \u003cp\u003eN (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.945\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHyponatremia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFall\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e7 (12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCardiovascular disease\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6 (15)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11 (19)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInfection\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOther\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11 (27)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMedication, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eThiazide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSSRI\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e5 (12)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e5 (9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.786\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eOpioids\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1 (2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4 (7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.608\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVolaemic status, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.215\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEuvolaemic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e21 (51)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e25 (42)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypervolaemic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12 (29)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e13 (22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHypovolaemic\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e8 (20)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21 (36)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdmission Na (mEq/L),\u003c/p\u003e \u003cp\u003eMean (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e121 (5.56)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e123 (4.95)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.178\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAdmission NA\u0026thinsp;\u0026le;\u0026thinsp;125, N(%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e36 (61)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.295\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNA delta (mEq/L) (48 hours), M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e6.8 (5.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e6.1 (5.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.518\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVolume retention (ml), M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e715(367)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e151(116)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.005\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLaboratory, M (SD)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eBun (mg/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30.7 (22.9)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e30.7 (24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.994\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCreatinine (mg/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.4 (1.4)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1.3 (1.2)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.762\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAlbumin (gr/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.3 (0.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.2 (0.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.105\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePotassium (mEq/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4.2 (0.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e4.3 (0.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.549\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHemoglobin (g/dL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.3 (1.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e10.9 (2.1)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.358\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWBC (10ᶺ3/uL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.2 (4.6)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.8 (14.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.820\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ePlatelets (10ᶺ3/uL)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e288.5 (99.8)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e232.5 (89.7)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.004\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTSH (mIU/L)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.1 (4.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.99 (3.5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.952\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eExitus, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2 (5)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e8 (14)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.278\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTreatment, N (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSaline 3%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e18 (31)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWater restriction\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e7 (17)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.580\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eFurosemide\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e13 (32)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e20 (34)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.990\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDrug withdrawal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e9 (22)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e14 (24)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.000\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNaCl 0.9%\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e30 (73)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e41 (70)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e.861\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003evan der Bilt F, Alsma J (2023) Hyponatraemia caused by transient syndrome of inappropriate antidiuresis to urinary retention. Intern Med J 53:285\u0026ndash;288\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoskowitz DW (1992) Functional obstructive uropathy: a significant factor in the hyponatremia of psychogenic polydipsia? J Urol 147:1611\u0026ndash;1613\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePyle R, Scott M, Bartholomew J et al (2011) Accidental polydipsia and hyponatremia from diphenhydramine urinary retention. Am J Med 124:e5\u0026ndash;6\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGalperin I, Friedmann R, Feldman H et al (2007) Urinary retention: a cause of hyponatremia? Gerontology 53:121\u0026ndash;124\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShapiro DS, Alexandrovich I, Sonnenblick M et al (2022) Prospective determination of the incidence and severity of hyponatraemia in older hospitalised patients with acute urinary tract obstruction. Age Ageing 51. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1093/ageing/afab234\u003c/span\u003e\u003cspan address=\"10.1093/ageing/afab234\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSyndrome of inappropriate antidiuretic hormone - Symptoms, diagnosis and treatment | BMJ Best Practice US\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hyponatraemia, urinary retention, older adults","lastPublishedDoi":"10.21203/rs.3.rs-4896469/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4896469/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eBackground\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHyponatraemia and urinary retention are common medical problems. Whilst associations between the two are documented, research has not clearly highlighted the prevalence of urinary retention in hyponatraemic patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObjectives\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eDetermining the prevalence of urinary retention in hyponatraemic patients and assessing whether urinary catheter insertion itself affects the correction rate.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA prospective, single centre, observational study including patients hospitalised in internal medicine and geriatric wards. A total of 199 patients were investigated: 100 with hyponatraemia ≤129 mEq/L, of these, 70 had severe hyponatraemia ≤125 mEq/L and 99 normonatraemic controls. The incidence of urinary retention was checked in all groups. Hyponatraemic patients underwent complete assessment for the cause of hyponatraemia and sodium levels were followed up for 48 hours.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere was a marked increase in the incidence of urinary retention in hyponatremic patients as compared to those with normal sodium levels (41% vs 21% p=0.004). When comparing to those with severe hyponatraemia, a slightly greater difference was found (44% vs 21% p=0.001). When comparing the hyponatraemic patients with and without urinary retention, there was no difference in sodium correction rate between the two groups. Patients with polyuria secondary to post obstructive diuresis had a more rapid sodium correction (9.2±6.8mEq/L vs 5.8±4.8mEq/L (p=0.05))\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions:\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThere is a significantly higher prevalence of urinary retention in patients with hyponatremia which is associated with the severity of hyponatraemia. Post obstructive diuresis following catheter insertion is a predictor of rapid sodium correction. We recommend a routine bladder scan for all patients with hyponatraemia.\u003c/p\u003e","manuscriptTitle":"Urinary Retention in Older Adults with Hyponatraemia admitted to Internal Medical and acute Geriatric wards","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-09-10 10:54:21","doi":"10.21203/rs.3.rs-4896469/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"cde75db9-f696-4509-9a2f-3f910e7281ad","owner":[],"postedDate":"September 10th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2024-11-06T10:39:30+00:00","versionOfRecord":[],"versionCreatedAt":"2024-09-10 10:54:21","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4896469","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4896469","identity":"rs-4896469","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}