Hereditary transthyretin amyloidosis in Sweden: Comparisons between a non-endemic and an endemic region

Introduction Hereditary transthyretin amyloidosis (ATTRv) is endemic in northern Sweden (Vasterbotten). The awareness of ATTRv amyloidosis is lower in Stockholm, a non-endemic region in Sweden. The aim of this study was to compare the possible differences in diagnostic delay, disease phenotypes, treatment and survival between a non-endemic and an endemic region in Sweden. Methods The in- and outpatient diagnosis registry at the Department of Neurology at Karolinska University Hospital and the Amyloidosis Centre at University Hospital of Umea were used to identify patients between January 2006 and November 2017. Results In total, 21 patients in Stockholm and 134 patients in Vasterbotten were included. The time between symptom onset to time-point of diagnosis was significantly longer in Stockholm vs Vasterbotten. This corresponded to a longer median time between first visit at amyloidosis centre to time-point of diagnosis in Stockholm vs in Vasterbotten. The most common reason for a diagnostic delay was negative tissue biopsies. Conclusion There was a diagnostic-, but no patient-delay in non-endemic Stockholm vs endemic Vasterbotten. Despite a more severe neuropathic phenotype in Stockholm at the onset, the systemic affection over the course of disease and of survival seems not to be influenced by the diagnosis delay in Stockholm.