The Role of ADMA as an Indicator of Progression in Early Stage of CKD

1. Summary

We are grateful for the time and effort you invested in reviewing our work. Below you will find our comprehensive responses to your comments, with corresponding modifications tracked in the accompanying revised file.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

The study addresses the association between FGF23, ADMA, and albuminuria. The current cross-sectional design limits the ability to draw conclusions about CKD progression or causality, and the language should reflect this. The manuscript would also benefit from careful proofreading to address grammatical issues and to adopt a more formal tone. If no prior studies have reported similar data from this region, highlighting that novelty would strengthen the rationale, particularly given the modest sample size and findings.

Can be improved

Our study provides preliminary evidence supporting ADMA as a biomarker for disease progression in early-stage of CKD. To our knowledge, our study was the first to investigate the associations between ADMA, FGF-23, and 25(OH)D with albuminuria in an adequate sample size and relatively homogeneous study population in Indonesia that minimized major confounding factors for these biomarker measurements.

3. Point-by-point response to Comments and Suggestions for Authors

Abstract

Response to Reviewer 2 Comments

1. Summary

We are grateful for the time and effort you invested in reviewing our work. Below you will find our comprehensive responses to your comments, with corresponding modifications tracked in the accompanying revised file.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

As the authors stated, ADMA, diabetes, hypertension, male, and CKD stage >3 are risk factors for CKD progression. Especially, a strong association between ADMA and albuminuria was observed. While this is an interesting study investigating the clinical meaning of ADMA in CKD, the reviewer has raised some major concerns.

Must be improved

We appreciate the reviewer's thoughtful evaluation and acknowledge the major concerns raised. We have carefully considered each point and provide detailed responses below, along with substantial revisions to address these issues

3. Point-by-point response to Comments and Suggestions for Authors

Comments 1: From a statistical standpoint, correlation should be assessed using a multivariate model that includes all covariates, rather than relying solely on bivariate analysis. Furthermore, the rationale for dichotomizing variables such as ADMA is unclear, which may lead to misinterpretation of the statistical analysis. Therefore, it is advisable to examine the correlation using continuous variables.

Response 1:

We are examining the correlation using with Spearman correlation showed in Table 2. This could be seen in line 175-177.

We are using multivariate model (seen in Table 3.) that includes all covariates. We divide the cut off of ADMA levels based on the study beforehand that stated the cut off of ADMA level was ≥0.69-μmol/L that could be seen in line 117-118

Multivariate analysis was used to find the covariates that associated with albuminuria ≥ 300 mg/g and resulting in ADMA levels ≥ 0.69 µmol/L showing the strongest correlation with p-value of 0.000 (OR 9.49 (3.18 – 28.25)). This finding supports our study's conclusion that elevated ADMA levels, in the presence of additional risk factors, accelerate the progression of chronic kidney disease. We attached the revised manuscript.

Comments 2: In a cross-sectional study, merely examining correlations between two variables does not justify concluding that one is a risk factor, as implied in the title and conclusion. Such statements may be misleading, given the limitations of cross-sectional data in establishing causality.

Response 2: Agree. We discussed and reach to a conclusion that our study limitation was due to the study design used was a cross-sectional, hence the albuminuria progression could not be monitored longitudinally over an extended period. But our study also has strength of its own that we’ve already put in line 317-321. We attached the revised manuscript.

Comments 3: These additional analyses may substantially alter the study results. If the findings remain unchanged, it would support the robustness of the study. However, if the results do change, it would be necessary to address and discuss the new findings in the Discussion section

Response 3: Thank you for the valuable input. We already discussed this with our team and reach to a conclusion that additional analysis will not be required since our analysis already shown strongest correlation with p-value of 0.000 between increase in ADMA level and albuminuria incidence. We attached the revised manuscript.

Comments 4: Please revise the text in lines 201 to 207.

Response 4: Thank you for the valuable correction. We already revised line 179-184. We attached the revised manuscript.

Response to Reviewer 3 Comments

1. Summary

We are grateful for the time and effort you invested in reviewing our work. Below you will find our comprehensive responses to your comments, with corresponding modifications tracked in the accompanying revised file.

2. Questions for General Evaluation

Reviewer’s Evaluation

Response and Revisions

The authors report a cross-sectional study of 107 non-dialysis CKD patients assessing relationships between FGF-23, 25(OH)D, ADMA and albuminuria. They find ADMA strongly correlated with albuminuria and ADMA ≥0.69 µmol/L independently associated with macroalbuminuria after multivariate adjustment. They report weaker correlations for FGF-23 and 25(OH)D.

The topic is clinically relevant: linking ADMA and mineral metabolism markers to albuminuria in CKD.

There is a reasonable sample size for a single-center cross-sectional biomarker study.

I have some comments to improve tha paper.

• Introduction:

I would add  more background information to better justify the aim of the study

Yes

Can be improved

We sincerely appreciate the reviewer's thorough evaluation and positive assessment of our work.

We appreciate the reviewer's thoughtful evaluation and acknowledge the major concerns raised. We have carefully considered each point and provide detailed responses below, along with substantial revisions to address these issues

3. Point-by-point response to Comments and Suggestions for Authors

Introduction

Comments 1: FFrom a clinical perspective, markers linked to albuminuria have implications for treatment choices in CKD. Management of hyperkalemia is increasingly recognized as central to allowing continued use of nephroprotective RAAS inhibitors, which themselves affect proteinuria and mineral metabolism. For example, Costa et al. (2023). Hyperkalemia in CKD: an overview of available therapeutic strategies. Frontiers in medicine, 10, 1178140, reviewed the management of hyperkalemia in CKD and its importance for maintaining treatment with RAAS inhibitors — a class known to reduce albuminuria and slow CKD progression. The current manuscript finds that low 25(OH)D and disturbed FGF-23 are linked to albuminuria, and that ADMA remains independently associated after adjustment. These results have therapeutic implications, since endothelial dysfunction and mineral metabolism abnormalities may coexist with hyperkalemia risk, potentially influencing RAAS inhibitor use. Citing and discussion this study would help connect the study’s biomarker findings to integrated CKD management strategies — particularly the safe continuation of RAAS blockade to control albuminuria

Response 1:

Thank you for the valuable input. We already revised the introduction by adding the usage of RAAS blockade to control albuminuria that could be seen in line 73-82. We attached the revised manuscript.

Comments 2: Imaging-based markers of intrarenal vascular and tubulointerstitial damage — such as the renal resistive index (RI) — are higher in CKD patients with diabetes, cardiovascular disease and disturbed mineral metabolism (including elevated phosphate), supporting a hemodynamic/interstitial pathway linking vascular dysfunction and progressive renal damage. Incorporating such perspectives suggests that our biochemical finding (ADMA–albuminuria association) may capture the same pathophysiological axis that associates disturbed mineral metabolism, vascular stiffening and renal structural damage. In particular, Provenzano et al. (2020). Renal resistive index in chronic kidney disease patients: Possible determinants and risk profile. PloS one, 15(4), e0230020, examined the renal resistive index (RI) as a non-invasive ultrasound marker of intrarenal vascular damage in CKD patients, showing that RI correlates with vascular stiffness, cardiovascular comorbidities, and altered mineral metabolism (including phosphate and FGF-23 disturbances). In the current manuscript, the independent association of ADMA with macroalbuminuria supports a similar pathophysiological link — ADMA reflects endothelial dysfunction and microvascular impairment, which may underlie increased albumin leakage. Citing and discussing this study would strengthen the argument that the biochemical marker (ADMA) in this study and the imaging marker (RI) in their study both capture a shared vascular–glomerular injury axis relevant to CKD progression

Response 2: Thank you for the valuable input. We already revised the introduction by adding the usage of imaging marker (RI) in their study both capture a shared vascular–glomerular injury axis relevant to CKD progression to strengthen the independent association of ADMA with macroalbuminuria supports that could be seen in line 64-69. We attached the revised manuscript.

1. Summary

We are grateful for the time and effort you invested in reviewing our work. Below you will find our comprehensive responses to your comments, with corresponding modifications tracked in the accompanying revised file.

2. Point-by-point response to Comments and Suggestions for Authors

Abstract

Comments 1: We recruited 85 participants to detect correlations of r ≥ 0.3 with adequate power”. Please report the actual power calculation (type1, type2 error C etc..) if it was performed. Otherwise, you can omit it.

Response 1: Thank you for the input, we revised our sentence. Therefore, we decided to revised the sentence in our sample section that can be found in line 135 page 3.

Comments 2: The conclusion still says that the investigation finds that ADMA is an (independent?) risk factor for accelerated CKD progression. This is a cross-sectional study..