Comments on abstract, title, references

The study quantifies variability between the initial and second oscillometric blood pressure reading in children using the same method and analysis technique as in adults previously published by the authors.

Condensed abstract. Although it is likely that out-of-office blood pressure readings would provide utility in diagnosis, there is no evidence in the manuscript that the consecutive office blood pressure readings have greater or less variability than out-of-office blood pressure monitoring. The last sentence should be reworded.

Referencing appropriate.

Comments on introduction/background

The analysis addresses consecutive office measurement of blood pressure, as done previously by the authors in adults. The study of within-visit blood pressure variability has not been addressed in the context of multiple blood pressure readings, excluding readings where consecutive differences are large (such as removing the first reading where differences are >10 mmHg), or variations upon such methods. Therefore, the manuscript introduction, title, abstract, and condensed abstract should, like the authors' previous article on the same topic in adults, emphasise the study of consecutive measurement of blood pressure, not within-visit blood pressure variability.

Comments on methodology

Methodology appropriate. However, statistical analysis uses SBP1 as the predictor variable of systolic variability. Some justification is required for using SBP1 instead of SBP2 (or SBP3) as the input variabile. Alternatively, the mean SBP would be a more logical input variable.

Comments on data and results

The result showing that variability is different between males and females is not presented in the results section and is required to justify the remainder of analysis treating males and females as separate groups.

Comments on discussion and conclusions

Discussion is appropriate. Conclusion reflects the study well.