Unraveling the Burden of Waldenström Macroglobulinemia: A Population-Based Study Using the NIS 2021 Database
Authors: Rajarajan Srinishant , Babu Kalaivani , Correa Amit , Roy Arya Mariam , Chattaraj Asmi , Ramesh Nithya , Ramanan Sruthi P , Ayanambakkam Attanathi Adanma Anji 
Published: December 2024

Background: Waldenstrom macroglobulinemia (WM) also known as lymphoplasmacytic lymphoma , is a low-grade B-cell lymphoproliferative neoplasm characterized by small lymphocytes and monoclonal IgM gammopathy. Understanding its clinical characteristics and outcomes can inform better management and treatment strategies. This study aims to analyse the clinical characteristics and outcomes of patients with WM.

Methods: We utilized the National Inpatient Sample 2021 data, using survey-weighted techniques to estimate WM prevalence and outcomes. Descriptive statistics were calculated for demographics, comorbidities, and hospital characteristics. Socioeconomic status (SES) was determined using income quartiles with Q1 denoting high income and Q4 denoting lower income. These values are derived from ZIP Code-demographic data obtained from Claritas. Primary outcome was mortality of patients with WM and logistic regression identified factors associated with mortality. Secondary outcomes included hospital length of stay (LOS) and total hospitalization charges (TOTCHG).

Results: The estimated total number of WM admissions was 9,860 during the study period. Among WM patients, 55.9% were male, and the mean age was 74.75 years. Majority of the patients were Whites (83.6%) followed by Black patients (6.7%), Hispanic (5.4%) and Asian/Pacific Islander (2.5%). Majority of the patients had increased comorbidities as evidenced by Charlson Comorbidity Index (CCI) score of 3 or higher (76.2%). Patients were distributed across income quartiles, with 18.6% in the lowest and 33.9% in the highest quartile. The majority of WM patients were treated in hospitals located in the South (54.6%), followed by the Midwest (24.4%) and the Northeast (21.5%).

The disease-specific mortality rate was 5.5% (95% CI: 4.5% - 6.5%). Higher CCI score (OR: 1.156, p= 0.001), and lower SES/low-income quartile (OR Q2: 0.457, p= 0.009; Q4: 0.563, p= 0.034) were significantly associated with mortality. Age, race, gender and hospital region were not significant predictors of mortality. The mean LOS was 6.45 days +/- add the range. Higher age (β: -0.038, p= 0.020) and higher CCI score (β: 0.253, p= 0.002) were significant predictors of LOS. The mean TOTCHG was $88,828 (range: $81,071 - $96,584). Factors associated with higher TOTCHG included higher age (β: -$1,416, p=0.001), treatment in teaching hospitals (β: $26,624, p&lt;0.001), and large hospital bed size (β: $31,249, p&lt;0.001).

Conclusion: Our study showed that WM patients with higher comorbidities and lower SES had higher mortality rates when admitted to hospitals. Additionally, higher age and comorbidities significantly impacted the length of stay. Higher age, treatment in teaching hospitals and large hospital bed size significantly affected hospitalisation costs. Greater care should be given to these specific patient groups to improve clinical outcomes for WM and reduce healthcare costs in the US.