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This 10-year retrospective analysis of 5 hospitals challenged the current dogma that rapid correction of hyponatremia is dangerous

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🎯 BRIEF SUMMARY:

• Study Overview
  • Multicenter cohort study on Osmotic Demyelination Syndrome (ODS) in hyponatremic patients across five academic hospitals in Toronto, Canada from 2010 to 2020
  • Objective: To determine the proportion of hospitalized hyponatremic patients who developed ODS
• Key Findings
  • Among 22,858 hyponatremia hospitalizations, 12 patients (0.05%) developed ODS
  • Rapid serum sodium correction occurred in 3,632 (17.7%) patients, yet only 5 (42%) of ODS cases experienced rapid correction
  • ODS patients had significantly lower initial serum sodium levels (mean 111 ± 10 mmol/L) compared to those without ODS (125 ± 4.6 mmol/L)
• Conclusions and Implications
  • Despite frequent rapid serum sodium correction, ODS was rare in this large cohort of hyponatremic patients
  • Further studies with more ODS cases are necessary to elucidate potential causal factors for the condition

DETAILED:

📚 BACKGROUND

• Osmotic Demyelination Syndrome (ODS) is a rare but potentially devastating neurologic complication of hyponatremia.

• Objective:

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  To identify the proportion of patients who developed ODS in a large, contemporary, multi-center cohort of patients admitted to hospital with hyponatremia.

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• Further Information (click to toggle)

🔎 METHODS

1. Study Setting
   • Multicenter cohort study of hyponatremic patients at five academic hospitals in Toronto, Ontario, Canada
   • Timeline: April 1, 2010 – December 31, 2020
2. Population
   1. All adult patients admitted with hyponatremia (serum sodium <130 mmol/L) were identified based on their initial serum sodium measurement upon presentation to the Emergency Department, admission, or transfer to general internal medicine
   2. Excluded: Patients who presented with serum sodium >130 mmol/L and subsequently developed hyponatremia in hospital
   3. Excluded: Patients with initial blood glucose of 25 mmol/L or higher (pseudohyponatremia)
   4. Excluded: Patients with a history of diabetes insipidus, as desmopressin acetate can affect serum sodium correction rate
3. Study Outcomes
   1. Primary Outcome
      1. Proportion of patients with hyponatremia who developed ODS during index admission (based on neuroimaging results from MRI or CT scanning)
   2. Secondary Outcome
      1. Rate of rapid serum sodium correction – defined as a change in serum sodium greater than 8 mmol/L in any 24-hour period from initial measurement until death, hospital discharge, or first measurement of ≥130 mmol/L
4. Statistical Analysis
   1. Descriptive statistics for patient-level characteristics and total length of hospitalization
   2. Stratification of ODS proportion according to initial serum sodium levels (<110, 110–119, ≥120 mmol/L)

📊 RESULTS

flowchart TD
    A[23,445 All admissions with initial serum sodium <130 mmol/L]
    A --> B[587 Excluded]
    B --> B1[27 Diagnosis of diabetes insipidus]
    B --> B2[560 Severe hyperglycemia]
    B1 & B2 --> C[22,858 Final cohort admissions: 
    - 5604 readmissions 
    - 17,254 unique patients]

• Cohort Size: 22,858 hospitalizations with hyponatremia
  • Sex: 50% women
  • Age: Mean 68 years
  • Initial Serum Sodium: 125 mmol/L (SD 4.6)
    • 86.9% with ≥120 mmol/L
    • 11.9% with 110–119 mmol/L
    • 1.2% with <110 mmol/L
• 3,632 (17.7%) patients experienced rapid correction of serum sodium