Diagnostic delay and characterization of the clinical prodrome in AL amyloidosis among 1523 US adults diagnosed between 2001 and 2019

Light-chain amyloidosis with dysphagia as the main symptom: a case report

BACKGROUND

Immunoglobulin light-chain amyloidosis is a relatively rare condition with a worldwide incidence of 5.1-12.8 cases per million person-years (Baker, 2022). It is characterized by a clonal population of immunoglobulin-secreting cells that produce a monoclonal light chain of κ or λ type as either an intact molecule or a fragment.

CASE PRESENTATION

A 69-year-old East Asian (Chinese) male patient who presented with progressive dysphagia visited multiple hospitals repeatedly for more than 2 years and was finally diagnosed with immunoglobulin light-chain amyloidosis.

CONCLUSIONS

Otolaryngologists should consider immunoglobulin light-chain amyloidosis when encountering suspicious clinical manifestations and intervene early to avoid misdiagnosis.

Breast calcifications on mammography from systemic amyloidosis: A case report

Calcifications on mammography from systemic disease at times meet diagnostic criteria for histologic sampling to exclude malignancy. We present a case of bilateral groups of new calcifications on mammography that yielded amyloidosis on core biopsy. Awareness of our patient's known diagnosis of systemic light chain amyloidosis (AL) prompted use of Congo red staining to confirm the histologic diagnosis. Knowledge of systemic diseases with possible manifestations on mammography can facilitate cogent and clinically relevant radiology-pathology correlation.

Healthcare resource utilisation and costs associated with AL amyloidosis: a retrospective matched cohort study

We conducted a retrospective population-based, matched cohort study using the National Health Insurance Research Database to estimate healthcare resource utilisation (HRU) and costs in patients with newly diagnosed AL amyloidosis in Taiwan. Cases were matched 10:1 by age, sex, and area of residence to patients without AL amyloidosis (comparators) randomly selected from the database during the same time period. Annual all-cause HRU and costs for 3 years were quantified. AL amyloidosis-attributable costs were obtained by subtracting all-cause HRU costs incurred by comparators from cases. The mean age of all patients was 60.78 years and 59.07% were male. Co-morbidities were more frequent in cases than comparators. By 6 months after diagnosis, 12.1% of cases had died versus 0.9% of comparators. In the first year, cases had 103% more outpatient visits, 177% more emergency room visits, were hospitalised 4-times more frequently, and spent 5.5-times more days in hospital than comparators, and total healthcare costs were > sixfold higher. Costs incurred during the first year after diagnosis accounted for 55% of the 3-year cumulative cost. High HRU costs associated with delayed diagnosis and end-organ damage indicate a need for earlier diagnosis and more effective treatments for AL amyloidosis.

Timing and co-occurrence of symptoms prior to a diagnosis of light chain (AL) amyloidosis

It is well-established that most patients with systemic light chain (AL) amyloidosis have multi-organ involvement and are often diagnosed after a lag period of increasing symptoms. We leverage electronic health record (EHR) data from the TriNetX research network to describe the incidence, timing, and co-occurrence of precursor conditions of interests in a cohort of AL amyloidosis patients identified between October 2015-December 2020. Nineteen precursor diagnoses of interest representing features of AL amyloidosis were identified using ICD codes up to 36 months prior to AL amyloidosis diagnosis. Among 1,401 patients with at least 36 months of EHR data prior to AL amyloidosis diagnosis, 46% were females, 16% were non-Hispanic Black, and 6% were Hispanic. The median age was 71 (range, 21-91) years. The median number of precursor diagnoses was 5 with dyspnea and fatigue being the most prevalent. The time from the first occurrence of a precursor to AL diagnosis ranged from 3.2 to 21.4 months. Analyses of pairwise co-occurrence of specific diagnoses indicated a high association (Cole's coefficient >0.6) among the examined precursor diagnoses. These findings provide novel information about the timing and co-occurrence of key precursor conditions and could be used to develop algorithms for early identification of AL amyloidosis.

Immunoglobulin light chain amyloidosis: 2024 update on diagnosis, prognosis, and treatment

DISEASE OVERVIEW

Immunoglobulin light chain amyloidosis is a clonal, nonproliferative plasma cell disorder in which fragments of immunoglobulin light or heavy chain are deposited in tissues. Clinical features depend on organs involved but can include heart failure with preserved ejection fraction, nephrotic syndrome, hepatic dysfunction, peripheral/autonomic neuropathy, and "atypical smoldering multiple myeloma or MGUS."

DIAGNOSIS

Tissue biopsy stained with Congo red demonstrating amyloid deposits with apple-green birefringence is required for the diagnosis of AL amyloidosis. Organ biopsy is not required in 85% of patients. Verification that amyloid is composed of immunoglobulin light chains is mandatory. The gold standard is laser capture mass spectroscopy.

PROGNOSIS

N-terminal pro-brain natriuretic peptide (NT-proBNP or BNP), serum troponin T(or I), and difference between involved and uninvolved immunoglobulin free light chain values are used to classify patients into four stages; 5-year survivals are 82%, 62%, 34%, and 20%, respectively.

THERAPY

All patients with a systemic amyloid syndrome require therapy to prevent deposition of amyloid in other organs and prevent progressive organ failure. Current first-line therapy with the best outcome is daratumumab, bortezomib, cyclophosphamide, and dexamethasone. The goal of therapy is a ≥VGPR. In patients failing to achieve this depth of response options for consolidation include pomalidomide, stem cell transplantation, venetoclax, and bendamustine.

FUTURE CHALLENGES

Delayed diagnosis remains a major obstacle to initiating effective therapy prior to the development of end-stage organ failure. Trials of antibodies to deplete deposited fibrils are underway.

Timing and co-occurrence of symptoms prior to a diagnosis of light chain (AL) amyloidosis

It is well-established that light chain (AL) amyloidosis patients have multi-organ involvement and are often diagnosed after a lag period of increasing symptoms. We leverage electronic health record (EHR) data from the TriNetX research network to describe the incidence, timing, and co-occurrence of precursor conditions of interests in a cohort of AL amyloidosis patients identified between October 2015-December 2020. Nineteen precursor diagnoses of interest representing features of AL amyloidosis were identified using ICD codes up to 36 months prior to AL amyloidosis diagnosis. Among 1,401 patients with at least 36 months of EHR data prior to AL amyloidosis diagnosis, 46% were females, 16% were non-Hispanic Black, and 6% were Hispanic. The median age was 71 (range, 21-91) years. The median number of precursor diagnoses was 5 with dyspnea and fatigue being the most prevalent. The time from the first occurrence of a precursor to AL diagnosis ranged from 3.2 to 21.4 months. Analyses of pairwise co-occurrence of specific diagnoses indicated a high association (Cole's coefficient > 0.6) among the examined precursor diagnoses. These findings provide novel information about the timing and co-occurrence of key precursor conditions and could be used to develop algorithms for early identification of AL amyloidosis.

Amyloid consults do not have to be vexing

Diagnosing amyloidosis can be challenging due to its clinical heterogeneity, need for multiple specialists to make a diagnosis, and lack of a single diagnostic test for the disease. Patients are often diagnosed late, in advanced stage, and after exhibiting multiple symptoms and signs for a long period. It is important to develop a clinical suspicion of amyloidosis, particularly in those with multisystemic symptoms and high-risk patient populations such as those with precursor hematologic conditions. A systematic approach to the workup of suspected amyloidosis is key, including a comprehensive clinical assessment, laboratory tests to assess organ involvement, advanced imaging studies, screening for plasma cell disorder, and tissue biopsy when necessary. After making a diagnosis of amyloidosis, accurate typing of amyloid deposits, differentiating between localized and systemic amyloidosis, and appropriately staging the disease is important. Early diagnosis is crucial for improving patient outcomes and quality of life in light chain amyloidosis.

Patient Journey Toward a Diagnosis of Light Chain Amyloidosis in a National Sample: Cross-Sectional Web-Based Study

BACKGROUND

Systemic light chain (AL) amyloidosis is a rare and multisystem disease associated with increased morbidity and a poor prognosis. Delayed diagnoses are common due to the heterogeneity of the symptoms. However, real-world insights from Chinese patients with AL amyloidosis have not been investigated.

OBJECTIVE

This study aimed to describe the journey to an AL amyloidosis diagnosis and to build an in-depth understanding of the diagnostic process from the perspective of both clinicians and patients to obtain a correct and timely diagnosis.

METHODS

Publicly available disease-related content from social media platforms between January 2008 and April 2021 was searched. After performing data collection steps with a machine model, a series of disease-related posts were extracted. Natural language processing was used to identify the relevance of variables, followed by further manual evaluation and analysis.

RESULTS

A total of 2204 valid posts related to AL amyloidosis were included in this study, of which 1968 were posted on haodf.com. Of these posts, 1284 were posted by men (median age 57, IQR 46-67 years); 1459 posts mentioned renal-related symptoms, followed by heart (n=833), liver (n=491), and stomach (n=368) symptoms. Furthermore, 1502 posts mentioned symptoms related to 2 or more organs. Symptoms for AL amyloidosis most frequently mentioned by suspected patients were nonspecific weakness (n=252), edema (n=196), hypertrophy (n=168), and swelling (n=140). Multiple physician visits were common, and nephrologists (n=265) and hematologists (n=214) were the most frequently visited specialists by suspected patients for initial consultation. Additionally, interhospital referrals were also commonly seen, centralizing in tertiary hospitals.

CONCLUSIONS

Chinese patients with AL amyloidosis experienced referrals during their journey toward accurate diagnosis. Increasing awareness of the disease and early referral to a specialized center with expertise may reduce delayed diagnosis and improve patient management.

Epidemiology and clinical outcomes of light-chain amyloidosis in Sweden: A nationwide population-based study

OBJECTIVES

This study evaluated data from six Swedish national registries to fill current evidence gaps on the epidemiology, clinical burden, and overall survival (OS) associated with light-chain (AL) amyloidosis.

METHODS

Patients newly diagnosed with AL amyloidosis were identified using six linked Swedish nationwide population-based registers. For each case, individuals from the general population were selected and matched with a maximum ratio of 1:5 based on age, sex, calendar year, and county.

RESULTS

846 patients newly diagnosed with AL amyloidosis and 4227 demographically matched individuals were identified. From 2011 to 2019, annual AL amyloidosis incidence increased from 10.5 to 15.1 cases per million. At baseline, patients with AL amyloidosis had a significantly higher disease burden including higher rates of cardiac and renal failure relative to the comparison group. Among patients with AL amyloidosis, 21.5% had incident heart failure and 17.1% had incident renal failure after initial diagnosis. Median OS for patients with AL amyloidosis was 56 months versus not reached in the matched general population comparison group.

CONCLUSION

The incidence of newly diagnosed AL amyloidosis in Sweden increased over time with AL amyloidosis being associated with a higher risk of cardiac/renal failure and all-cause mortality compared with the general population.

Clinical characteristics and prognosis of a Chinese cohort with systemic light chain amyloidosis: a single-center study

Light chain amyloidosis is a plasma cell dyscrasia characterized by deposition of misfolded amyloid fibrils in tissues, leading to multi-organ dysfunction. We retrospectively analyzed 335 patients (median age, 60 years) with systemic light chain amyloidosis in the First Hospital of Peking University from 2011 to 2021. Involved organs were the kidney (92.8%), heart (57.9%), liver (12.8%) and peripheral nervous system (6.3%). Chemotherapy was administered to 55.8% (187/335) of patients, among whom 94.7% received novel agent-based regimens. Hematologic response (≥ very good partial response) was achieved in 63.4% of patients who received chemotherapy. Only 18.2% of patients received autologous hematopoietic stem cell transplant (ASCT). Among transplant-eligible patients, the overall survival of ASCT recipients was better than those who received chemotherapy only. The median overall survival of the patients with light chain amyloidosis was 77.5 months. Estimated glomerular filtration rate and Mayo 2012 stage were independent prognostic factors for overall survival in multivariate analysis. Although the younger age and high ratio of renal involvement might contribute to the favorable prognosis of this cohort, the role of novel agents and ASCT is also discernible. This study will provide a comprehensive perspective on progress in treatment of light chain amyloidosis in China.

A clinically-guided unsupervised clustering approach to recommend symptoms of disease associated with diagnostic opportunities

OBJECTIVES

A first step in studying diagnostic delays is to select the signs, symptoms and alternative diseases that represent missed diagnostic opportunities. Because this step is labor intensive requiring exhaustive literature reviews, we developed machine learning approaches to mine administrative data sources and recommend conditions for consideration. We propose a methodological approach to find diagnostic codes that exhibit known patterns of diagnostic delays and apply this to the diseases of tuberculosis and appendicitis.

METHODS

We used the IBM MarketScan Research Databases, and consider the initial symptoms of cough before tuberculosis and abdominal pain before appendicitis. We analyze diagnosis codes during healthcare visits before the index diagnosis, and use k-means clustering to recommend conditions that exhibit similar trends to the initial symptoms provided. We evaluate the clinical plausibility of the recommended conditions and the corresponding number of possible diagnostic delays based on these diseases.

RESULTS

For both diseases of interest, the clustering approach suggested a large number of clinically-plausible conditions to consider (e.g., fever, hemoptysis, and pneumonia before tuberculosis). The recommended conditions had a high degree of precision in terms of clinical plausibility: >70% for tuberculosis and >90% for appendicitis. Including these additional clinically-plausible conditions resulted in more than twice the number of possible diagnostic delays identified.

CONCLUSIONS

Our approach can mine administrative datasets to detect patterns of diagnostic delay and help investigators avoid under-identifying potential missed diagnostic opportunities. In addition, the methods we describe can be used to discover less-common presentations of diseases that are frequently misdiagnosed.

In-hospital mortality in amyloid light chain amyloidosis: analysis of the Premier Healthcare Database

Aim: Describe the clinical and economic burden of hospitalizations for amyloid light chain (AL) amyloidosis. Materials & methods: This retrospective analysis used nationally representative hospital discharge data (2017-2020) to report discharge status, resource use and costs for hospitalizations among patients with AL amyloidosis. Results: Of 1341 patients identified, 92% were discharged alive and 8% experienced in-hospital death. Compared with the average US hospital stay during 2017-2019 (4.7 days, mean costs of $13,046 and mean charges of $54,496), hospital stays for AL amyloidosis were longer and costlier (9.7 days, $27,098.61, $111,233.91), especially in patients with in-hospital death (12.2 days, $44,966, $182,338.18). Conclusion: AL amyloidosis is associated with significant clinical and economic burden.

Immunoglobulin Light Chain Amyloidosis: Diagnosis and Risk Assessment

Immunoglobulin light chain (AL) amyloidosis is a clonal plasma cell disorder with multiple clinical presentations. The diagnosis of AL amyloidosis requires a high index of suspicion, making a delay in diagnosis common, which contributes to the high early mortality seen in this disease. Establishing the diagnosis of AL amyloidosis requires the demonstration of tissue deposition of amyloid fibrils. A bone marrow biopsy and fat pad aspirate performed concurrently have a high sensitivity for the diagnosis of AL amyloidosis and negate the need for organ biopsies in most patients. An accurate diagnosis requires amyloid typing via additional testing, including tissue mass spectrometry. Prognostication for AL amyloidosis is largely driven by the organs impacted. Cardiac involvement represents the single most important prognostic marker, and the existing staging systems are driven by cardiac biomarkers. Apart from organ involvement, plasma cell percentage on the bone marrow biopsy, specific fluorescence in situ hybridization findings, age at diagnosis, and performance status are important prognostic markers. This review elaborates on the diagnostic testing and prognostication for patients with newly diagnosed AL amyloidosis.

Restrictive Atrial Dysfunction in Cardiac Amyloidosis: Differences between Immunoglobulin Light Chain and Transthyretin Cardiac Amyloidosis Patients

Background: In cardiac amyloidosis, the prevalence of thromboembolic events and atrial fibrillation is higher in transthyretin amyloidosis compared to immunoglobulin light chain amyloidosis. Therefore, we hypothesize that transthyretin cardiac amyloidosis patients have worse atrial function. Purpose: To explore the left atrial function by conventional ultrasound and strain analysis in immunoglobulin light chain- and transthyretin cardiac amyloidosis patients. Methods: In cardiac amyloidosis patients in our Amyloidosis Expert Center, echocardiographic strain analysis was performed using speckle tracking. Results: The data of 53 cardiac amyloidosis patients (83% male, mean age 70 years) were analyzed. Transthyretin cardiac amyloidosis patients (n = 24, 45%) were older (75 ± 5.6 vs. 65 ± 7.2 years, p < 0.001) and had more left ventricular (LV) hypertrophy than immunoglobulin light chain cardiac amyloidosis patients (n = 29, 55%). However, LV systolic and diastolic function did not differ, nor did left atrial dimensions (LAVI 56(24) vs. 50(31) mL/m2). Left atrial reservoir strain was markedly lower in transthyretin cardiac amyloidosis (7.4(6.2) vs. 13.6(14.7), p = 0.017). This association was independent of other measurements of the left atrial and ventricular function. Conclusions: Transthyretin cardiac amyloidosis patients had lower left atrial reservoir function compared to immunoglobulin light chain cardiac amyloidosis patients although the left atrial geometry was similar. Interestingly, this association was independent of left atrial- and LV ejection fraction and global longitudinal strain. Further research is warranted to assess the impact of impaired left atrial dysfunction in transthyretin cardiac amyloidosis on atrial fibrillation burden and prognosis.

Evaluation of the cardiac amyloidosis clinical pathway implementation: a real-world experience

Aims

The aim of this study is to evaluate the implementation of the cardiac amyloidosis (CA) clinical pathway on awareness among referring cardiologists, diagnostic delay, and severity of CA at diagnosis.

Methods and results

Patients with CA were retrospectively included in this study and divided into two periods: pre-implementation of the CA clinical pathway (2007-18; T1) and post-implementation (2019-20; T2). Patients' and disease characteristics were extracted from electronic health records and compared. In total, 113 patients (mean age 67.8 ± 8.5 years, 26% female) were diagnosed with CA [T1 (2007-18): 56; T2 (2019-20): 57]. The number of CA diagnoses per year has increased over time. Reasons for referral changed over time, with increased awareness of right ventricular hypertrophy (9% in T1 vs. 36% in T2) and unexplained heart failure with preserved ejection fraction (22% in T1 vs. 38% in T2). Comparing T1 with T2, the diagnostic delay also improved (14 vs. 8 months, P < 0.01), New York Heart Association Class III (45% vs. 23%, P = 0.03), and advanced CA stage (MAYO/Gillmore Stage III/IV; 61% vs. 33%, P ≤ 0.01) at time of diagnosis decreased.

Conclusion

After implementation of the CA clinical pathway, the awareness among referring cardiologists improved, diagnostic delay was decreased, and patients had less severe CA at diagnosis. Further studies are warranted to assess the prognostic impact of CA clinical pathway implementation.