The Journey to Diagnosis of Light Chain Amyloidosis: A Real-World Experience from a Single Center in Latin America

Light chain (AL) amyloidosis is a form of systemic amyloidosis, causing organ dysfunction; mainly affecting heart and kidneys. Due to the non-specific clinical manifestations, diagnosis is challenging and patients experience a long journey and treatment delay. Consequently, AL amyloidosis patients have extensive organ involvement at the time of diagnosis which implies a poor prognosis. Early diagnosis of AL amyloidosis is of paramount importance. There is limited real-world data from Latin America regarding the time from initial patient reported symptom onset to diagnosis.

This retrospective cohort study aimed to assess clinical and laboratory characteristics, diagnostic journey, and outcomes of patients with AL amyloidosis treated in a medical care program in Argentina.

AL amyloidosis patients were identified using a 12-year follow-up data (January 1, 2010 to December 31, 2022) from the institutional registry of amyloidosis (IRA).The IRA is registered in ClinicalTrials.gov (NCT01347047) and is approved by the IRB (CEPI 1635). Diagnosis of AL amyloidosis was confirmed by tissue biopsy staining positive with Congo red in addition to the demonstration of a monoclonal plasma cell proliferative disorder and the presence of amyloid-related systemic syndrome.The symptoms and signs related to amyloidosis were selected based on previously reported data in the literature. The number of medical consultations and health care resource utilization was collected from electronic medical records of patients in the medical care program. fThe statistical analyses were performed with Stata version 13.0. The continuous variables were presented as mean and standard deviation (SD) or median and interquartile range (IQR), and the categorical variables were presented as absolute frequencies and percentages. The survival rate was estimated by Kaplan-Meier.

From 181807 community patients included in the comprehensive health care program, 28 patients were diagnosed with AL amyloidosis and included in the study. The median age at diagnosis was 73 (IQR, 66.5-80.5) years old and 64% (n=18) were female (Table 1).Heart and kidney were the most frequently affected organs. The median time from the first sign and/or symptom related to AL amyloidosis to diagnosis was 15.9 months (IQR, 8.8-38.2). Only 4 patients (14%) were diagnosed within the first six months since the onset of symptoms. Prior to diagnosis, the median number of symptoms and/or signs presented by the patients was 4 (IQR, 3.5-7). The median number of medical consultations prior to diagnosis was 3 (IQR, 1-5). The most consulted medical specialties were internal medicine (n=24, 86%), cardiology (n=14, 50%) and nephrology (n=10, 36%). Twelve patients (43%) were hospitalized at least once before diagnosis and 4 (14%) were hospitalized at least 3 times. Ten (36%) patients were diagnosed during a hospitalization. Involvement of more than three organs was present in 25% (n=7) of the patients. Fifty-seven percent (n=16) had cardiac involvement, mostly in advanced stages. Out of 23 patients that underwent treatment, 22 patients were treated with bortezomib based regimens in first line; 3 in combination with anti CD38. The median overall survival was 21 months (IQR, 4.6-49.8). The one-year overall survival rate after diagnosis was 55% (95% CI 34-71). The one-year overall survival rate for patients diagnosed within the first 12 months from the onset of symptoms was 70% (95% CI 32-89), while for those diagnosed after 12 months from the onset of symptoms, it was 45% (95% CI 20-67).

This study provides real-world evidence about the diagnostic journey of AL amyloidosis patients in Latin America. AL amyloidosis is a complex disease with diverse manifestations, leading to diagnostic challenges even with growing awareness among the medical community. Patients often underwent a diagnostic odyssey involving multiple specialists and hospitalizations before the definitive diagnosis is reached.