Endocrine Abstracts

Aims: Hiponatremia is the most frequent electrolyte disturbance. Our aim is to retrospectively analyze the diagnosis of hyponatremia in the discharge sheets of a tertiary hospital during 5 years

Method: Data from the MBDS (Minimum Basic Data Set) of the discharged patients from the Hospital Clínico San Carlos (Madrid) between the years 2005 and 2009 was analysed. The 5th Edition of the ICD-9-CM was used for the codification of the diagnoses and procedures. The system of patient classification of diagnosis related groups – AP-DRG (version 21.0) – was used for the grouping of discharge processes. The Charlson index was use as a measure of comorbidity. Patients with a main or secondary diagnosis of hyponatremia were analyzed. Age, sex, length of stay, comorbidity, procedures and mortality were taken into account.

Resultados: Concerning destiny after discharge, 81.6% go home, 1.4% to another hospital and 2.8% to a nursing home. Mortality was 13.1 vs 4.3% among the general population. We found a statistically significant difference between hyponatremic patients and the rest concerning destiny to nursing homes (0.8 vs 1.6%) and in the univariate analysis for the mortality rate between hyponatremic patients and the rest: 13.1 vs 4.3%.

Discusion: The first important observation of our study is the extremely low prevalence of hyponatremia in our series (1.5%). In some series, mild hyponatremia has been reported to be 30 and 2.5% of patients show sodium levels below 125 mmol/l. We have observe an increased in mortality for hyponatremic patients; alter correcting for other confusing variables, patients with hyponatremia have 23% more possibilities of dying than dose with normal sodium levels. Our observations showed the importance of treating this frequently underdiagnosed disturbance and its negative prognostic implications on hospital admittances.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.