Elevated blood potassium levels predict readmission risk among elderly patients of HF

A new article published in Heart and Vessels Journal suggest that in older patients with heart failure (HF), elevated blood potassium levels are linked to the outcome event of readmission within a year.

Blood potassium levels in patients with congestive heart failure are linked to poor outcomes. Uncertainty surrounds whether older individuals with varying blood potassium levels at the time of emergency readmission within a year experience distinct outcome occurrences. Gechu Shan and his team therefore carried out the study to examine the serum potassium level and its impact on the elderly after a year of readmission.

This study combined electronic medical records from the PhysioNet restricted health data database with external outcome data to analyze data from individuals hospitalized with HF. Researchers used baseline data, laboratory tests, comorbidities, and medication use as covariates to examine the effect of serum potassium levels on outcome events, with readmission within a year being the primary outcome, in a retrospective study of HF patients aged 60 and older.

The key findings of the study were:

1. The sample size was determined a priori, and the total number of elderly HF patients included in this retrospective cohort study was 788. Of these, 20.3% had hypokalemia (K+ 3.5 mmol/L) and 14.7% had hyperkalemia (K+ > 4.7 mmol/L).

2. Patients with hyperkalemia had a shorter time between readmissions within a year, according to a multivariate Cox regression model, with a hazard ratio (HR) and its 95% confidence interval (CI) of 1.134. (1.006–1.279).

3. After correction, three models were used to analyze patients with various blood potassium levels.

4. There were significant differences in outcome events between the high potassium group and the low and normal groups, with HRs and their 95% CIs of 1.266 (1.03-1.557), 1.245 (1.01-1.534), and 1.439 (1.142-1.812), respectively.

5. Competing risk models with subgroup analysis that showed that blood potassium levels had a steady effect on outcome events and were unaffected by covariates further illustrated the model's robustness (age, diabetes, sex, chronic kidney disease, high-sensitivity troponin, NT-proBNP, and glomerular filtration rate).

Reference:

Shang, G., Gao, Y., Liu, K., & Wang, X. (2022). Serum potassium in elderly heart failure patients as a predictor of readmission within 1 year. In Heart and Vessels. Springer Science and Business Media LLC. https://doi.org/10.1007/s00380-022-02192-y