Rate of Correction and All-Cause Mortality in Patients With Severe Hypernatremia

Importance Hypernatremia is common among hospitalized patients and is associated with high mortality rates. Current guidelines suggest avoiding fast correction rates but are not supported by robust data. Objective To investigate whether there is an association between hypernatremia correction rate and patient survival. Design, Setting, and Participants This retrospective cohort study examined data from all patients admitted to the Tel Aviv Medical Center between 2007 and 2021 who were diagnosed with severe hypernatremia (serum sodium ≥155 mmol/L) at admission or during hospitalization. Statistical analysis was performed from April 2022 to August 2023. Exposure Patients were grouped as having fast correction rates (>0.5 mmol/L/h) and slow correction rates (≤0.5 mmol/L/h) in accordance with current guidelines. Main Outcomes and Measures All-cause 30-day mortality. Results A total of 4265 patients were included in this cohort, of which 2621 (61.5%) were men and 343 (8.0%) had fast correction rates; the median (IQR) age at diagnosis was 78 (64-87) years. Slow correction was associated with higher 30-day mortality compared with fast correction (50.7% [1990 of 3922] vs 31.8% [109 of 343]; P < .001). These results remained significant after adjusting for demographics (age, gender), Charlson comorbidity index, initial sodium, potassium, and creatinine levels, hospitalization in an ICU, and severe hyperglycemia (adjusted odds ratio [aOR], 2.02 [95% CI, 1.55-2.62]), regardless of whether hypernatremia was hospital acquired (aOR, 2.19 [95% CI, 1.57-3.05]) or documented on admission (aOR, 1.64 [95% CI, 1.06-2.55]). There was a strong negative correlation between absolute sodium correction during the first 24 hours following the initial documentation of severe hypernatremia and 30-day mortality (Pearson correlation coefficient, −0.80 [95% CI, −0.93 to −0.50]; P < .001). Median (IQR) hospitalization length was shorter for fast correction vs slow correction rates (5.0 [2.1-14.9] days vs 7.2 [3.5-16.1] days; P < .001). Prevalence of neurological complications was comparable for both groups, and none were attributed to fast correction rates of hypernatremia. Conclusions and Relevance This cohort study of patients with severe hypernatremia found that rapid correction of hypernatremia was associated with shorter hospitalizations and significantly lower patient mortality without any signs of neurologic complications. These results suggest that physicians should consider the totality of evidence when considering the optimal rates of correction for patients with severe hypernatremia.