Population aging increases functional decline, underscoring the role of geriatric rehabilitation in restoring functional capacity after hospitalization or community referral. Yet, patient trajectories in geriatric rehabilitation remain poorly characterized. This cohort study analyzed Swiss national administrative claims (2015–2022) of adults aged ≥65 years comparing temporal trends in geriatric rehabilitation and acute-care hospitalizations. Main outcomes included causes of hospitalizations, length of stay, DRG-based cost weight, in-hospital mortality, and 30-day rehospitalization. Among 4,030,691 hospitalizations, 125,990 (3.1%) involved geriatric rehabilitation, mostly in acute-care hospitals (76.3%), followed by geriatric (20.5%) and other facilities (3.2%). Geriatric rehabilitation admissions increased by 8.3% annually (95% confidence interval [CI]: 5.2–11.5) versus 1.2% (95% CI: 0.3–2.2) in acute-care. Circulatory diseases were the leading cause of acute-care admissions (19.3%), while injuries predominated in geriatric rehabilitation (25.1%) and showed the steepest increase (+9.7% annually; 95% CI: 6.3–13.1), followed by circulatory, musculoskeletal, and mental disorders. Length of stay declined more in geriatric rehabilitation (−4.3% per year; 95% CI: −4.9-−3.7) than in acute care (−2.0%; 95% CI: −2.2-−1.9). DRG-based cost weight decreased annually by -3.09% (95% CI: −4.60%-−1.57%) but remained stable in acute care. Discharge home after geriatric rehabilitation declined by − 1.2% per year (95% CI: −1.6-−0.7), with increasing transfers to other rehabilitation and nursing homes. 30-day rehospitalization and in-hospital mortality were stable in both groups. In conclusion, the proportion of hospitalizations involving geriatric rehabilitation is rising, reflecting growing demand in an aging population. Its effectiveness for patient outcomes and health system performance warrants further evaluation.

The final year of life accounts for a disproportionate share of health-care utilization. Characterizing hospitalization patterns, causes, and interventions during this period, and examining how these trajectories differ by frailty, is crucial for anticipating needs and improving end-of-life care. In this retrospective cohort study using Swiss national administrative claims of adults aged ≥65 years (2013-2022), we assessed temporal trends in hospitalizations within 1 year of death. The main outcome included causes of hospitalizations and number of invasive care interventions, stratified by frailty. Among 186,349 older adults, causes of hospitalization and interventions remained largely stable over time, with cardiac disease, cancer and injury-related conditions predominating. In frailer individuals, psychiatric and neurological conditions were more frequent in addition to injuries and cardiac diseases. Overall, 51.1% of individuals were hospitalized within the final three months of life. Among less frail individuals, cancer-related hospitalizations increased substantially (8.7% at 12 months before death to 26.6% in the last month of life, standardized mean difference [SMD] −0.482, p < 0.001), whereas in frailer individuals, the absolute increase was smaller (1.4% to 6.1%, SMD -0.252, p < 0.001), alongside increases observed for cardiac (10.1% to 18.3%, SMD -0.238 p < 0.001) and infectious diseases (9.5% to 15.7%, SMD -0.189 p < 0.001). Intervention rates increased modestly near death (39.4% to 42.0%, SMD −0.053, p = 0.005). In conclusion, hospitalization trajectories in the last year of life differ by frailty, with cancer dominating in the less frail and non-cancer causes in the frail. Tailored approaches are needed to improve alignment of end-of-life care.

BACKGROUND: When Cox regression models are used to analyse time-to-event data, the proportional hazard assumption (PHA) must be reassured to obtain valid results. Transparent reporting of the statistics used is therefore essential to interpret research. This study aimed to assess the quality of statistical reporting and testing of the PHA in subgroup analysis of surgical randomised controlled trials (RCTs). METHODS: All published articles (see appendix 1) in the top quartile (25%) of surgical journals from 2019 to 2021 were screened in a literature review according to the ClarivateTM journal citation report impact factor. Subgroup analyses of surgical RCT data that used Cox models were identified. Statistical reporting was rated using a previously established 12-item PHA Reporting Score as our primary endpoint. For original surgical publications, the PHA was formally tested on reconstructed time-to-event data from Kaplan-Meier estimators. Methodological reporting quality was rated according to the CONSORT statement. Digitalisation was only possible in studies where a Kaplan-Meier estimator including numbers at risk per time interval was published. All results from the subgroup analyses were compared to primary surgical RCT reports and benchmark RCTs using Cox models published in the New England Journal of Medicine and The Lancet. RESULTS: Thirty-two studies reporting secondary subgroup analyses on surgical RCT data using Cox models were identified. Statistical reporting of surgical subgroup publications was significantly inferior compared to original benchmark publications: median PHA Reporting Score 50% (interquartile range [IQR]: 39 to 58) vs 58% (IQR: 42 to 67), p <0.001. The subgroups did not differ in comparison to primary surgical RCTs: median PHA Reporting Score 50% (IQR: 39 to 58) vs 42% (IQR: 33 to 58), p = 0.286. Adherence to the CONSORT reporting standards did significantly differ between subgroup studies and benchmark publications (p <0.001) as well as between subgroup studies and primary surgical RCT reports: 13 (12.5 to 14) vs 13 (IQR: 11 to 13), p = 0.042. CONCLUSION: Statistical methodological reporting of secondary subgroup analyses from surgical RCTs was inferior to benchmark publications but not worse than primary surgical RCT reports. A comprehensive statistical review process and statistical reporting guidelines might help improve the reporting quality.

OBJECTIVE:There is increasing evidence that multisystem morbidity in patients with Cushing's disease (CD) is only partially reversible following treatment. We investigated complications from multiple organs in hospitalized patients with CD compared to patients with nonfunctioning pituitary adenoma (NFPA) after pituitary surgery. DESIGN:Population-based retrospective cohort study using data from the Swiss Federal Statistical Office between January 2012 and December 2021. METHODS:Through 1:5 propensity score matching, we compared hospitalized patients undergoing pituitary surgery for CD or NFPA, addressing demographic differences. The primary composite endpoint included all-cause mortality, major adverse cardiac events (ie, myocardial infarction, unstable angina, heart failure, cardiac arrest, and ischemic stroke), hospitalization for psychiatric disorders, sepsis, severe thromboembolic events, and fractures in need of hospitalization. Secondary endpoints comprised individual components of the primary endpoint and surgical reintervention due to disease persistence or recurrence. RESULTS:After matching, 116 patients with CD (mean age 45.4 years [SD, 14.4], 75.0% female) and 396 with NFPA (47.3 years [14.3], 69.7% female) were included and followed for a median time of 50.0 months (IQR 23.5, 82.0) after pituitary surgery. Cushing's disease presence was associated with a higher incidence rate of the primary endpoint (40.6 vs 15.7 events per 1000 person-years, hazard ratio [HR] 2.75; 95% CI, 1.54-4.90). Cushing's disease patients also showed increased hospitalization rates for psychiatric disorders (HR 3.27; 95% CI, 1.59-6.71) and a trend for sepsis (HR 3.15; 95% CI, .95-10.40). CONCLUSIONS:Even after pituitary surgery, CD patients faced a higher hazard of complications, especially psychiatric hospitalizations and sepsis.

BACKGROUND:ChatGPT-4 is the latest release of a novel artificial intelligence (AI) chatbot able to answer freely formulated and complex questions. In the near future, ChatGPT could become the new standard for health care professionals and patients to access medical information. However, little is known about the quality of medical information provided by the AI.OBJECTIVE:We aimed to assess the reliability of medical information provided by ChatGPT.METHODS:Medical information provided by ChatGPT-4 on the 5 hepato-pancreatico-biliary (HPB) conditions with the highest global disease burden was measured with the Ensuring Quality Information for Patients (EQIP) tool. The EQIP tool is used to measure the quality of internet-available information and consists of 36 items that are divided into 3 subsections. In addition, 5 guideline recommendations per analyzed condition were rephrased as questions and input to ChatGPT, and agreement between the guidelines and the AI answer was measured by 2 authors independently. All queries were repeated 3 times to measure the internal consistency of ChatGPT.RESULTS:Five conditions were identified (gallstone disease, pancreatitis, liver cirrhosis, pancreatic cancer, and hepatocellular carcinoma). The median EQIP score across all conditions was 16 (IQR 14.5-18) for the total of 36 items. Divided by subsection, median scores for content, identification, and structure data were 10 (IQR 9.5-12.5), 1 (IQR 1-1), and 4 (IQR 4-5), respectively. Agreement between guideline recommendations and answers provided by ChatGPT was 60% (15/25). Interrater agreement as measured by the Fleiss κ was 0.78 (P<.001), indicating substantial agreement. Internal consistency of the answers provided by ChatGPT was 100%.CONCLUSIONS:ChatGPT provides medical information of comparable quality to available static internet information. Although currently of limited quality, large language models could become the future standard for patients and health care professionals to gather medical information.

Background: Physical restraints are frequently used in acute care hospitals. Their application is associated with negative outcomes, while their intended preventive effect is debated. Objectives: To determine the prevalence of physical restraints and associated outcomes on medical wards in a tertiary care hospital. Methods: Retrospective cohort study (January 2018 to December 2021). We included all adult medical in-patients and excluded patients with admission to the intensive care unit, short stays (length of stay (LOS) < 48 h), and patients declining informed consent. Results: Of 11,979 admissions, the prevalence of patients with at least one restraint was 6.4% (n = 772). Sensor mats were used most frequently (73.0%, n = 666), followed by blanket restrictions (14.5%, n = 132), bedrails (8.8%, n = 80) and belts (3.7%, n = 34). On average, restraints were applied 19 h (standard deviation (SD) ± 161) before a fall. Average restraint duration was 42 h (SD ± 57). Patients with a restraint had longer LOS 8 days (IQR 5–14) vs. 5 days (IQR 3–9). Median nurses’ time expenditure was 309 h (IQR 242–402) vs. 182 h (IQR 136–243) for non-restrained patients. Patients with restraints fell more often (22.5% vs. 2.7%) and were more likely to die (13.3% vs. 5.1%). These differences persisted after adjusting a regression model for important clinical confounders. We saw a decline in the duration of restraints over the years, but no variation between wards. Conclusion: Approximately 6% of medical patients, mostly older and severely ill, were affected by restraint use. For the first time, we report data over 4 years up to ward-level granularity.

BACKGROUND: We recently compared the effects of bedside and outside the room ward rounds on patients’ knowledge about their medical care. Here, we report preferences of medical and nursing staff members regarding outside versus bedside ward rounds. METHODS: Within this ancillary project of a large multicentre randomised controlled trial, we prospectively conducted a survey of medical and nursing staff members participating in the weekly consultant ward rounds in the internal medicine division of three Swiss teaching hospitals between July 2017 and October 2019. Participants were asked about their preferences on outside versus bedside ward rounds. The primary endpoint was satisfaction of healthcare workers with the ward round measured with a visual analogue scale from 0 to 100. RESULTS: Between July 2017 and October 2019, 919 patients were included in the trial, and we received 891 survey responses (nurses 15.6%, residents 26.8%, attending physicians 29.6%, consultants 7.8% and chief physicians 20.2%. In the overall analysis, mean (± standard deviation) satisfaction of healthcare workers was higher with outside the room than bedside ward rounds (78.03 ± 16.96 versus 68.25 ± 21.10 respectively; age-, gender- and centre-adjusted difference of –10.46, 95% confidence interval [CI] –12.73 to –8.19; p <0.001). Healthcare workers reported better time management, more discussion of sensitive topics and less discomfort when case presentations were conducted outside the room. A stratified subgroup analysis considering the profession, however, showed strong differences, with nurses being more satisfied with bedside rounds (69.20 ± 20.32 versus 65.32 ± 20.92, respectively; adjusted difference 4.35, 95% CI –1.79 to 10.51; p <0.001), whereas attending physicians showed higher satisfaction with outside the room rounds (82.63 ± 13.87 versus 66.59 ± 21.82; adjusted difference –16.51, 95% CI –20.29 to –12.72; p = 0.002). CONCLUSIONS: While bedside ward rounds are considered more patient centred and are preferred by the nursing staff, physicians prefer outside the room presentation of patients during ward rounds because of the perceived better discussion of sensitive topics, better time management and less staff discomfort. Continuous training including medical communication techniques may help to increase satisfaction of physicians with bedside ward rounds. Trial registration: https://clinicaltrials.gov/ct2/show/NCT03210987

Background Glucocorticoid (GC)-induced hyperglycemia is a frequent adverse effect in hospitalized patients. Guidelines recommend insulin treatment to a target range of 6–10 mmol/L (108–180 mg/dl), but efficacies of particular regimes have not been well-studied. Methods In this retrospective cohort study, hospitalized patients receiving GCs at the medical ward were analyzed by treatment (basal-bolus vs. bolus-only vs. pre-mixed insulin) and compared to a non-insulin-therapy reference group. Coefficients of glucose variation (CV), percentage of glucose readings in range (4–10 mmol/L (72–180 mg/dl)) and hypoglycemia (< 4 mmol/L (< 72 mg/dl)) were evaluated. Results Of 2424 hospitalized patients receiving systemic GCs, 875 (36%) developed GC-induced hyperglycemia. 427 patients (17%) had a previous diagnosis of diabetes. Adjusted relative risk ratios (RRR) for the top tertile of CV (> 29%) were 1.47 (95% Cl 1.01–2.15) for bolus-only insulin, 4.77 (95% CI 2.67–8.51) for basal-bolus insulin, and 4.98 (95% CI 2.02–12.31) for premixed insulin, respectively. Adjusted RRR for percentages of glucose readings in range were 0.98 (95% Cl 0.97–0.99) for basal-bolus insulin, 0.99 (95% Cl 0.98–1.00) for premixed insulin, and 1.01 (95% Cl 1.00–1.01) for bolus-only insulin, respectively. Adjusted RRR for hypoglycemia was 13.17 (95% Cl 4.35–39.90) for basal-bolus insulin, 8.92 (95% Cl 2.60–30.63) for premixed insulin, and 2.99 (95% Cl 1.01–8.87) for bolus-only insulin, respectively. Conclusions Current guidelines recommend a basal-bolus regimen for treatment of GC-induced hyperglycemia, but we found similar outcomes with pre-mixed and bolus-only insulin regimens. As GC-induced hyperglycemia is a frequent issue in hospitalized patients, it might be reasonable to prospectively study the ideal regimen.

Abstract Inherited metabolic disorders (IMDs) comprise a heterogeneous class of genetic disorders characterized by impaired biochemical functions in metabolism. However, incidences and outcomes of patients hospitalized with IMDs are largely unknown. We conducted a population‐based cohort study using nationwide in‐hospital claims data in Switzerland from 2012 to 2020. We assessed incidence rates of hospitalizations and hospital‐associated outcomes, stratified in five age groups (0–9, 10–19, 20–39, 40–59, and 60–90 years) and three types of IMDs (peptide, amine and amino acid metabolism disorders [AD], carbohydrate metabolism disorders [CD], fatty acid, and ketone body metabolism disorders [FD]). A total of 7293 hospitalizations with IMD were identified, of which 3638 had AD, 3153 CD, and 502 FD. Incidence rates for hospitalizations per 100 000 person‐years were highest under the age of 10 years across all types of IMDs (8.69 for AD, 5.73 for CD, 3.71 for FD) and decreased thereafter. In patients with AD and CD, hospitalization rates increased again in adults aged 60–90 years (7.28 for AD, 7.25 for CD), while they remained low in patients with FD (0.31). Compared to inpatients without IMD, adult IMD patients had a higher burden of hospital‐associated adverse outcomes including an increased risk of in‐hospital mortality, intensive care unit admission, mechanical ventilation, and longer length of hospital or intensive care unit stay. Incremental risk of 30‐day, 1‐year, and 2‐year hospital readmission was highest among children and adolescents with IMD.

Searchable abstracts of presentations at key conferences in endocrinology ISSN 1470-3947 (print) | ISSN 1479-6848 (online)

BACKGROUND:Although bedside case presentation contributes to patient-centered care through active patient participation in medical discussions, the complexity of medical information and jargon-induced confusion may cause misunderstandings and patient discomfort.OBJECTIVE:To compare bedside versus outside the room patient case presentation regarding patients' knowledge about their medical care.DESIGN:Randomized, controlled, parallel-group trial. (ClinicalTrials.gov: NCT03210987).SETTING:3 Swiss teaching hospitals.PATIENTS:Adult medical patients who were hospitalized.INTERVENTION:Patients were randomly assigned to bedside or outside the room case presentation.MEASUREMENTS:The primary endpoint was patients' average knowledge of 3 dimensions of their medical care (each rated on a visual analogue scale from 0 to 100): understanding their disease, the therapeutic approach being used, and further plans for care.RESULTS:Compared with patients in the outside the room group (n = 443), those in the bedside presentation group (n = 476) reported similar knowledge about their medical care (mean, 79.5 points [SD, 21.6] vs. 79.4 points [SD, 19.8]; adjusted difference, 0.09 points [95% CI, -2.58 to 2.76 points]; P = 0.95). Also, an objective rating of patient knowledge by the study team was similar for the 2 groups, but the bedside presentation group had higher ratings of confusion about medical jargon and uncertainty caused by team discussions. Bedside ward rounds were more efficient (mean, 11.89 minutes per patient [SD, 4.92] vs. 14.14 minutes per patient [SD, 5.65]; adjusted difference, -2.31 minutes [CI, -2.98 to -1.63 minutes]; P < 0.001).LIMITATION:Only Swiss hospitals and medical patients were included.CONCLUSION:Compared with outside the room case presentation, bedside case presentation was shorter and resulted in similar patient knowledge, but sensitive topics were more often avoided and patient confusion was higher. Physicians presenting at the bedside need to be skilled in the use of medical language to avoid confusion and misunderstandings.PRIMARY FUNDING SOURCE:Swiss National Foundation (10531C_ 182422).

BACKGROUND:Delays in patient discharge can not only lead to deterioration, especially among geriatric patients, but also incorporate unnecessary resources at the hospital level. Many of these delays and their negative impact may be preventable by early focused screening to identify patients at risk for transfer to a post-acute care facility. Early interprofessional discharge planning is crucial in order to fit the appropriate individual discharge destination. While prediction of discharge to a post-acute care facility using post-acute care discharge score, the self-care index, and a combination of both has been shown in a single-center pilot study, an external validation is still missing.OBJECTIVE:This paper outlines the study protocol and methodology currently being used to replicate the previous pilot findings and determine whether the post-acute care discharge score, the self-care index, or the combination of both can reliably identify patients requiring transfer to post-acute care facilities.METHODS:This study will use prospective data involving all phases of the quasi-experimental study "In-HospiTOOL" conducted at 7 Swiss hospitals in urban and rural areas. During an 18-month period, consecutive adult medical patients admitted to the hospitals through the emergency department will be included. We aim to include 6000 patients based on sample size calculation. These data will enable a prospective external validation of the prediction instruments.RESULTS:We expect to gain more insight into the predictive capability of the above-mentioned prediction instruments. This approach will allow us to get important information about the generalizability of the three different models. The study was approved by the institutional review board on November 21, 2016, and funded in May 2020. Expected results are planned to be published in spring 2021.CONCLUSIONS:This study will provide evidence on prognostic properties, comparative performance, reliability of scoring, and suitability of the instruments for the screening purpose in order to be able to recommend application in clinical practice.INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID):DERR1-10.2196/21447.

Glucocorticoids are frequently prescribed in inflammatory diseases and have recently experienced a boom in the treatment of COVID‐19. Small studies have shown an effect of glucocorticoids on inflammatory marker levels, but definitive proof is lacking. We investigated the influence of prednisone on inflammatory biomarkers in a previous multicenter, randomized, placebo‐controlled trial that compared a 7‐day treatment course of 50‐mg prednisone to placebo in patients hospitalized with community‐acquired pneumonia. We compared levels of C‐reactive protein (CRP), procalcitonin (PCT), leukocyte and neutrophil count between patients with and without glucocorticoid treatment at baseline and on days 3, 5, and 7 and at discharge by Wilcoxon tests and analysis of variance. A total of 356 patient data sets in the prednisone group and 355 in the placebo group were available for analysis. Compared to placebo, use of prednisone was associated with reductions in levels of CRP on days 3, 5, and 7 (mean difference of 46%, P < .001 for each time point). For PCT, no such difference was observed. Leukocyte and neutrophil count were higher in the prednisone group at all time points (mean difference of 27% for leukocytes and 33% for neutrophils, P <.001 for all time points). We conclude that after administration of glucocorticoids in community‐acquired pneumonia, patients had lower CRP levels and increased leukocyte and neutrophil count as compared to the placebo group. PCT levels were not different between treatment groups. PCT levels thus may more appropriately mirror the resolution of infection compared to more traditional inflammatory markers.

BACKGROUND AND AIMS:The nutritional risk screening (NRS 2002) is a validated screening tool for malnutrition. This study aims to investigate the prognostic value of the NRS 2002 and its individual components regarding long-term mortality and adverse outcomes in a well-characterized cohort of medical inpatients.METHODS:We performed a 5-year follow-up investigation of patients included in the investigator-initiated, prospective, randomized controlled multicenter EFFORT trial that evaluated the effects of individualized nutritional intervention vs. standard hospital food. We used multivariable cox regression analyses adjusted for randomisation arm, study centre, comorbidities and main admission diagnosis to investigate associations between NRS 2002 total scores at time of hospital admission and several long-term outcomes.RESULTS:We had confirmed mortality data over the mean follow-up time of 3.2 years in 1874 from the initial cohort of 2028 EFFORT patients. Mortality showed a step-wise increase in patients with NRS 3 (289/565 [51.2%]) and NRS 4 (355/717 [49.6%]) to 59.5% (353/593) in patient with NRS≥5 corresponding to an adjusted Hazard Ratio (HR) of 1.28 (95%CI 1.15 to 1.42, p ≤ 0.001) for mortality after one year and 1.13 (95%CI 1.05 to 1.23, p = 0.002) for the overall time period. All individual components of NRS including disease severity, food intake, weight loss and BMI provided prognostic information regarding long-term mortality risk.CONCLUSION:Nutritional risk mirrored by a NRS 2002 total score is a strong and independent predictor of long-term mortality and morbidity in polymorbid medical inpatients particularly in patients with high nutritional risk with an NRS ≥5 points.

Context: Hyponatremia has been associated with excess long-term morbidity and mortality. However, effects during hospitalization are poorly studied. Objective: The objective of this work is to examine the association of hyponatremia with the risk of in-hospital mortality, 30-day readmission, and other short-term adverse events among medical inpatients. Design and Setting: A population-based cohort study was conducted using a Swiss claims database of medical inpatients from January 2012 to December 2017 Patients: Hyponatremic patients were 1:1 propensity-score matched with normonatremic medical inpatients. Main Outcome Measure: The primary outcome was a composite of all-cause in-hospital mortality and 30-day hospital readmission. Secondary outcomes were intensive care unit (ICU) admission, intubation rate, length-of-hospital stay (LOS), and patient disposition after discharge. Results: After matching, 94 352 patients were included in the cohort. Among 47 176 patients with hyponatremia, 8383 (17.8%) reached the primary outcome compared with 7994 (17.0%) in the matched control group (odds ratio [OR] 1.06 [95% CI, 1.02-1.10], P= .001). Hyponatremic patients were more likely to be admitted to the ICU (OR 1.43 [95% CI, 1.37-1.50], P< .001), faced a 56% increase in prolonged LOS (95% CI, 1.52-1.60, P< .001), and were admitted more often to a postacute care facility (OR 1.38 [95% CI 1.34-1.42, P< .001). Of note, patients with the syndrome of inappropriate antidiuresis (SIAD) had lower in-hospital mortality (OR 0.67 [95% CI, 0.56-0.80], P< .001) as compared with matched normonatremic controls. Conclusion: In this study, hyponatremia was associated with increased risk of short-term adverse events, primarily driven by higher readmission rates, which was consistent among all outcomes except for decreased in-hospital mortality in SIAD patients.

CONTEXT:Hyponatremia is the most prevalent electrolyte disturbance in hospitalized patients. Previous studies have shown a seasonal variation of profound hyponatremia with higher prevalence during warmer months. OBJECTIVE:This study aimed at analyzing the seasonal prevalence and sex- and age-specific differences of hyponatremia in medical inpatients. DESIGN:Nationwide cohort study from January 2009 and December 2015 using prospective administrative data. SETTING:Medical inpatients. PATIENTS:Diagnosis of hypoosmolar hyponatremia. MAIN OUTCOME MEASURES:The primary outcome was the monthly alteration in hyponatremia prevalence. Secondary outcomes were the association of outdoor temperature with hyponatremia prevalence and differences among sex and age groups. RESULTS:Of 2 426 722 medical inpatients, 84 210 were diagnosed with hypoosmolar hyponatremia, of whom 61% (n = 51 262) were female. The highest overall prevalence of hyponatremia was observed in July (4.5%, n = 8976); the lowest in December (2.7%, n = 6530). The overall prevalence of hyponatremia in women compared with men was higher by 58% (odds ratio [OR], 1.58; 95% confidence interval [CI], 1.56-1.60). The sex-specific difference was most pronounced in the warmest month of July (mean temperature 20.1°C (OR, 1.76; 95% CI, 1.68-1.84). We observed the strongest association between seasonality and hyponatremia in elderly (>80 years) female inpatients admitted during the month of July (OR, 2.40; 95% CI, 2.20-2.62]). CONCLUSION:The prevalence of diagnosed hypoosmolar hyponatremia in medical inpatients increases during summer months with higher outdoor temperature. Elderly female inpatients were most susceptible to the seasonal rise in hyponatremia prevalence.