Systemic and iatrogenic factors contribute to the development of severe hypernatraemia in vulnerable inpatients.

Objectives: To determine all‐cause in‐hospital mortality associated with severe hypernatraemia and the causes, comorbidities, time to treatment, discharge destination and postdischarge mortality. Design: Retrospective observational cohort study. Patients: Severe hypernatraemia, (sodium concentration ≥ 155 mmol/L), at any time during a tertiary hospital admission in Melbourne, Australia, 1 January 2019 to 31 December 2019 (pre‐COVID19). Measurements: Deaths, Charlson Comorbidity Index (CCI), hypernatraemia causes, time to treatment, discharge destination. Results: One hundred and one inpatients: 64 community‐acquired, 37 hospital‐acquired. In‐hospital mortality was 38%, but cumulative mortality was 65% by 1 month after discharge, with only a minor further increase at 6 and 12 months. After adjusting for peak sodium concentration, the community acquired group had significantly reduced odds of in‐hospital mortality (odds ratio 0.15, 95% confidence interval [0.04−0.54], p =.003). Iatrogenic factors were present in 57% (21/37) of the hospital‐acquired group. Only 55% of all cases received active sodium directed treatment. Time to start treatment did not affect outcomes. High levels of comorbidity were present, median CCI (IQR) was 6 (5−8) in the community and 5 (4−7) in the hospital group. Dementia prevalence was higher in the community group, 66% (42/64) versus 19% (7/37) (p =.001). Infection was the most common precipitant with 52% (33/64) in the community and 32% (12/37) in the hospital group. Of the survivors, 32% who had been living independently required residential care after discharge. Conclusions: Mortality was high and loss of independence in survivors common. To potentially improve outcomes, hypernatraemia‐specific guidelines should be formulated and efforts made to reduce system and iatrogenic factors. [ABSTRACT FROM AUTHOR]