On the development and validation of the SXS model for ADHF.

To the Editor

We read with great interest the article by Soni, et al., titled “Do we need a simplified model to predict outcomes in patients hospitalized with Acute Decompensated Heart Failure? Results from the Role of Sodium in Heart Failure Outcomes Prediction ('SHOUT-PREDICTION') study.” While this study appropriately highlighted the importance of SBP and serum sodium as prognostic indicators in ADHF, there were some limitations that we would like to discuss:

The study did not divide the sample into model derivation and model validation groups. Traditionally, predictive models are built on a training data set, and then evaluated on a separate validation data set. We recommend that the authors re-evaluate their model on a data set that was not used to derive the model to truly ascertain its predictive power.

The study concluded that serum urea and creatinine were non-significant predictors of patient outcomes, despite the fact that the ADHERE risk tree incorporates both factors in its risk stratification process. Considering that the ADHERE algorithm was developed on a sample of 33,046 patients, whereas the present study is based on 130 patients, it is likely that the present study is underpowered.

The exclusion of COPD and ACS patients limits the SXS model's utility and generalizability, as some of the most common precipitants of ADHF are acute exacerbation of COPD and ischemia. Due to these exclusion criteria, the SXS model may lack a strong predictive value for mortality risk in these patients.

Despite the limitations described, this study highlights the significance of using serum sodium to predict mortality risk for ADHF patients, a component absent in currently-used models. Further investigation into this area with higher powered studies is necessary, as it could improve clinical decision-making for the treatment of ADHF.

Ethics approval

This study was exempt from Institutional Review Board approval.

Funding information

No funding was provided for this study.

Declaration of competing interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.