Thank you for showing interest in our recent article on Paget disease of bone (PDB). We have addressed your queries below.
This disease appears to be more common in south India based on the number of cases and case series reported in the Indian literature so far (Ref: 8,9,11,17-64 in the article). Prevalence of any disease is generally considered to be overrated when published from an institute due to the possible referral bias. The cases reported in this paper were seen in private outpatient clinics of mainly two authors and moreover two major case series from India are also from Vellore (near Chennai, South India). In addition, as mentioned in our article, the series from North had pooled patients from all over India and not exclusively from that region. Thus we strongly feel that this disease probably has some predominance in south India. However, this needs more exploration with prospective collaborative studies from all zones. Bisphosphonates especially zoledronate has been shown to be very efficacious in PDB remission. This study reiterates the same observation. The patients included in this study had atleast 1 year follow up following zoledronate. The last patient was followed up in January 2020 and hence the time period was mentioned as until 2020. All the series from the west (17 cases), north (21 cases - out of which only 4 were from Chandigarh) and south (51 cases) were published in 2006, but the number of cases from south was strikingly more than the other zones. In 2018, another large series from Vellore (south) was published that excluded the cases from their previous series but there were no major case series from any other zone since 2006 other than isolated case reports. In our paper, we had mentioned as the largest cohort that has ever been studied in India since we had included 66 patients. FDG PET scan was not done in all patients as it is not required for diagnosis. But out of 66 patients in our series, 6% of patients underwent FDG PET scan for their symptoms during work up elsewhere and were incidentally diagnosed to have PDB and referred for management. Remission was defined as clinical improvement and normalisation of alkaline phosphatase which occurred in 61 out of 66 patients in 1 year and hence the remission percentage was calculated as 92.4%.
We hope that your questions have been satisfactorily answered in our reply. We thank you again for giving us the opportunity.
Dr. Shriraam Mahadevan
Professor & Head, Department of Endocrinology, Sri Ramachandra Medical College and Research Institute, Porur, Chennai – 600116, Tamil Nadu, India
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Conflicts of interest
There are no conflicts of interest.