Influence of corticosteroids on QUS parameters of the calcaneus in the 1st year after renal transplantation: authors’ reply to Dr. Adamczyk

Abstract

The intention-to-treat analysis of our study on renal transplant recipients randomized to 3 days or 4 months of corticosteroids revealed no difference in quantitative ultrasound (QUS) parameters in the 1st year after renal transplantation. In our opinion, intention-to-treat analysis is the only methodologically robust way to study such differences. Results of post hoc analysis of subgroups of patients are less reliable due to inevitable bias and should be handled with caution. Anyhow, as stated in the manuscript, exclusion of the patients in the steroid-free group who were treated with steroids did not change the results. Also, as described in our study, and in contrast to Dr. Adamczyk’s statement, no statistically significant difference in changes in QUS parameters was found between the two groups. The difference at 12 months after transplantation in broadband ultrasound attenuation (BUA) between the two groups was −1.4% in favour of the steroidtreated group (95% confidence interval: −5.6 to +2.7%). Correlation analysis of the changes in QUS parameters at all time points and cumulative steroid dose performed was not significant (P>0.05). We agree that factors other than the moderate corticosteroid dose administered explain the changes in QUS parameters found. Parathyroid hormone (PTH) at baseline was weakly correlated with changes in BUA in the study between zero and 12 months after transplantation (r=0.33, P<0.05), so hyperparathyroidism is one of the factors involved. No correlation however was found between the changes in QUS parameters and graft function at 12 months after transplantation. Our study group was not large enough to allow further division into smaller subgroups. In conclusion, our study reveals that QUS parameters are not importantly influenced by a moderate dose of corticosteroids in the 1st year after renal transplantation. Of course, an influence of larger doses of corticosteroids is not excluded by our study.