Reproducibility and Accuracy of the Radiofrequency Echographic Multi-Spectrometry for Femoral Mineral Density Estimation and Discriminative Power of the Femoral Fragility Score in Patients with Primary and Disuse-Related Osteoporosis
, Francesca Bardesono 3, Marco Di Monaco 3, Lorenzo Lippi 4, Marco Invernizzi 4,5 and Marco Alessandro Minetto 1,*
Round 1
Reviewer 1 Report
Authors presents the research on the reproducibility and accuracy of radiofrequency echographic multi-spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. The main conclusions of the research are: REMS provide excellent test-retest reproducibility; the diagnostic adequacy between DXA and REMS is minimal/poor.
The article seems to be well presented, but the fourth finding in “Discussions” chapter “REMS–derived femoral fragility score discriminated between non-fractured and fractured patients in both populations of patients” seems to be excessively optimistic as (authors say about it in lines 326-330) “several non-fractured patients with primary osteoporosis had a fragility score above the median value of fragility score” and results in figure 4 do not shows clear discriminative power of the method (except statistical test). Could this discriminative power be enhanced including other parameters?
The word “probability” should be replaced by the “probably” in sentence at lines 329-330 “this subgroup of non-fractured patients could probability be considered at increased fracture risk”.
Author Response
REVIEWER
Authors presents the research on the reproducibility and accuracy of radiofrequency echographic multi-spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. The main conclusions of the research are: REMS provide excellent test-retest reproducibility; the diagnostic adequacy between DXA and REMS is minimal/poor.
The article seems to be well presented, but the fourth finding in “Discussions” chapter “REMS–derived femoral fragility score discriminated between non-fractured and fractured patients in both populations of patients” seems to be excessively optimistic as (authors say about it in lines 326-330) “several non-fractured patients with primary osteoporosis had a fragility score above the median value of fragility score” and results in figure 4 do not shows clear discriminative power of the method (except statistical test). Could this discriminative power be enhanced including other parameters?
ANSWER
We thank the Reviewer for the appreciation of the work and for the suggestion to introduce a note of caution in the statements relative to the discriminative power of the femoral fragility score.
In the revised manuscript, we highlighted that different subgroups (non-fractured vs fractured patents) showed differences in the fragility score and that “further studies are required to establish whether the fragility score has true discriminative power for different subgroup of patients and can therefore be considered a relevant predictor of the fracture risk”.
Moreover, the following sentence has been included:
“its discriminative power could be proved through a longitudinal study investigating the occurrence of fragility fractures in non-fractured patients presenting different baseline fragility scores”.
REVIEWER
The word “probability” should be replaced by the “probably” in sentence at lines 329-330 “this subgroup of non-fractured patients could probability be considered at increased fracture risk”.
ANSWER
The typo has been corrected.
Reviewer 2 Report
1. Please what is DXA in the abstract 2. Line 46-48: need reference 3. 61-63: need reference 4. 71-73: the originality as proposed by the authors is very clear but by searching on pubmed i saw a lot of papers on this subject, thus, the authors should explain the originality of this study Materials and methods: 5. the number of the patients? 6. Any sample size test? 7.how can we use the two groups, one of 35 patients and the other of 140? Can we compare it? 8. Please use a, b, c.... for all the multi panels figures 9. Table 2: please mark in bold or with asterisk the significant results
Author Response
We thank the Reviewer for the appreciation of the work and for constructive comments.
REVIEWER
Please what is DXA in the abstract
ANSWER
The meaning of the acronym has been specified.
REVIEWER
Line 46-48: need reference
ANSWER
Two references have been added.
REVIEWER
61-63: need reference
ANSWER
Two references have been added.
REVIEWER
71-73: the originality as proposed by the authors is very clear but by searching on pubmed i saw a lot of papers on this subject, thus, the authors should explain the originality of this study
ANSWER
We thank the Reviewer for this comment. Although REMS is a recently developed technique, it already received considerable research attention during the last years. However, the previous studies did not investigate the research gaps we aimed to fill.
The originality of our study has been highlighted, as requested, with the addition of the following sentence:
“no previous study adopted REMS to investigate spinal cord injured patients and no previous study investigated the reproducibility and discriminative power of the femoral fragility score in osteoporotic patients”
REVIEWER
Materials and methods: the number of the patients?
ANSWER
The requested info has been added.
REVIEWER
Any sample size test?
ANSWER
We thank the Reviewer for this comment. Yes, the sample size estimation for REMS reproducibility analysis has been performed according to the method previously proposed by Walter et al. This detail has been added, as follows:
“A sample size of at least 30 subjects (in each of the two groups) was considered necessary for the test-retest reproducibility analysis, using the approximate method developed by Walter et al. [22] based on α=0.05 and β=0.20, indicating an expected level of reproducibility (ρ1) of 0.98 [3] and a minimally acceptable level of reproducibility (ρ0) of 0.95”.
REVIEWER
how can we use the two groups, one of 35 patients and the other of 140? Can we compare it?
ANSWER
We agree with the Reviewer. The two groups differed in many variables (age, gender distribution, severity of osteoporosis): therefore, no between-group comparison was performed. For all the statistical tests (with the inclusion of the REMS reproducibility assessment) the two populations were considered separately.
REVIEWER
Please use a, b, c.... for all the multi panels figures
ANSWER
All figures have been modified, as suggested.
REVIEWER
Table 2: please mark in bold or with asterisk the significant results
ANSWER
All ICCs were statistically significant and are highlighted in bold in Table 2.
Reviewer 3 Report
The paper investigates the reproducibility and accuracy of radiofrequency Echo graphic Multi-Spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. REMS showed excellent test-retest reproducibility, but the diagnostic concordance between DXA and REMS was between minimal and poor. The authors may need to consider the following comments to improve the final paper:
1. introduction section can be improved with more relevant references.
2. Some Operation symbols must be corrected.
3. Table 1 must be improved.
Author Response
REVIEWER
The paper investigates the reproducibility and accuracy of radiofrequency Echo graphic Multi-Spectrometry (REMS) for femoral BMD estimation and the reproducibility and discriminative power of the REMS-derived femoral fragility score. REMS showed excellent test-retest reproducibility, but the diagnostic concordance between DXA and REMS was between minimal and poor.
ANSWER
We thank the Reviewer for the appreciation of the work and for constructive comments.
REVIEWER
Introduction section can be improved with more relevant references.
ANSWER
Several references have been added to the Introduction, as suggested by two Reviewers.
REVIEWER
Some Operation symbols must be corrected.
ANSWER
The typos have been corrected.
REVIEWER
Table 1 must be improved.
ANSWER
Table 1 has been modified, as suggested.
Round 2
Reviewer 2 Report
good answers and modifications
