Light-chain amyloidosis with renal involvement: renal outcomes and validation of two renal staging systems in the Chinese population

The Clinical Characteristics of Immunoglobulin Light Chain Amyloidosis in the Chinese Population: A Systematic Scoping Review

Immunoglobulin light chain (AL) amyloidosis is the most common type of systemic amyloidosis in China and is associated with increased morbidity and a poor prognosis. However, the clinical characteristics of Chinese patients with AL amyloidosis have not been systematically investigated. This scoping review aimed to summarize the available literature regarding the clinical characteristics of patients with AL amyloidosis and identify potential knowledge gaps. We searched three electronic databases from inception to 7 February 2021. PICOS (Patient, Intervention, Comparison, Outcome and Study) design structure was used to formulate the data extraction. All statistical calculations and analyses were performed with R (version 3.6.0). Sixty-seven articles with 5022 patients were included. Results suggest Chinese patients were younger (57 years) at the time of diagnosis when compared with other patient populations and were predominantly male (61.2%). The time interval from the onset of symptoms to diagnosis was between 6 and 12 months. It was found that 41.1% of Chinese patients with AL amyloidosis were diagnosed with an advanced stage III disease when diagnosed, and 20.2% had a concurrent disease. The most involved organs were the kidneys (84.3%) and the heart (62.5%). In conclusion, our study shows some similarities and differences with other studies on the clinical characteristics of Chinese patients with AL amyloidosis, including the age at diagnosis, Mayo stage, and organ involvement. However, a nationwide epidemiological investigation is still needed to provide a comprehensive overview of this patient population in China.

A prognostic staging system for light-chain amyloidosis using hepatic and renal indicator data from 1,064 Chinese patients

Background

Light-chain (AL) amyloidosis frequently involves severe multiple end-organ damage, thus affecting prognosis. As the current disease staging system is based only on cardiac indicators, we propose a new staging system based on multiple organ indicators to supplement the existing system.

Methods

Patients with AL amyloidosis (n=1,064) from 18 Chinese hospitals were enrolled and divided into test and validation cohorts (4:1). Multivariate analyses were performed to identify the clinical and laboratory factors for inclusion in the new staging system.

Results

A score of 1 was assigned for each of the following-the difference between the involved and uninvolved free light chains ≥100 mg/L, estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m², total bilirubin (Tbil) ≥18 µmol/L, cardiac troponin I ≥0.06 µg/L, and N-terminal pro-brain natriuretic peptide (NT-proBNP) ≥3,600 pg/mL-to divide the patients into five disease stages (0 to IV). There were 220 (20.7%), 291 (27.3%), 251 (23.6%), 178 (16.7%), and 124 (11.7%) patients with stage 0, I, II, III, and IV disease, respectively. Patients with stage II, III, and IV disease had a median overall survival (OS) of 56.9 months [95% confidence interval (CI), 33.9-not reached (NR)], 18.6 months (95% CI, 33.9-NR), and 6.5 months (95% CI, 8.0-24.6) (P<0.001), respectively. The 3-year survival estimates for patients with stages 0, I, II, III, and IV were 90.7%, 71.4%, 59.4%, 39.0%, and 22.1%, respectively.

Conclusions

The new staging system has been developed that incorporates plasma cell-related characteristics in addition to cardiac, renal, and hepatic function parameters. It enhances the risk stratification of patients with AL amyloidosis and is useful when multiple organs are involved.

Renal Involvement in Systemic Amyloidosis Caused by Monoclonal Immunoglobulins

Kidney involvement in immunoglobulin-related amyloidosis (AIg) is common. Although patients with renal-limited AIg tend not to have the high mortality that patients with cardiac amyloidosis have, they do experience significant morbidity and impact on quality of life. The complexity of the pathogenesis remains incompletely understood. Models have been established to prognosticate and assess for the response to therapy. Patients with advanced renal impairment from immunoglobulin light chain amyloidosis still have poor renal prognosis, and better therapy is needed in order to preserve kidney function. Patients who develop end-stage renal disease can undergo renal replacement therapy with kidney transplantation.