Author`s Reply.

To the Editor,

We thank the author(s) for their special comments on our study entitled “Admission serum potassium level is associated with in-hospital and long-term mortality in ST-elevation myocardial infarction” published in the Anatolian Journal of Cardiology 2015; 16: 10-15. In the study, we determined the association between cardiovascular outcomes and admission serum potassium (sK) levels (1). In our study, we found that there was a significant relation between admission sK levels >4.5 mmol/L and mortality (1). Another notable finding of the study was the significant relation between ventricular arrhythmias and sK levels <3 mmol/L and ≥5 mmol/L (1). These findings of our study support the findings of the previous studies (2, 3).

In the study, we determined the effect of admission sK levels on outcomes rather than the sK levels during the in-hospital period. Therefore, we did not evaluate the impact of insulin therapy on sK levels and outcomes. We mentioned about this condition in the limitations section. The effect of insulin therapy on sK levels and clinical outcomes could be studied in another research.

In addition, being a retrospective study, it has some potential limitations. The coronary artery disease extensiveness and severity was not recorded and studied. Moreover, the aim of the study was the relation between admission sK levels and clinical outcomes. The coronary artery disease extensiveness and severity was not our priority.

Because the time of the ventricular arrhythmias was not recorded, as mentioned in limitations section, we also did not classify ventricular arrhythmias, but rather we evaluated all ventricular arrhythmias together.

Although sK levels are extensively affected by medication, we studied the admission sK levels, and we did not evaluate the effect of medication on sK levels. The effect of medication and diuretics on sK levels could be a part of another study. With regard to previous medication, we did not categorize the diuretics because of the small number of patients using diuretics; however, there was no significant difference between the groups (p=0.27).

The authors stated that the relation between the follow-up sK levels and cardiovascular events should be studied in further randomized clinical trials. In the study we conducted, we investigated the relationship between admission sK levels and cardiovascular outcomes rather than the in-hospital sK levels and difference.