Background

HCL is a rare chronic B-cell lymphoproliferative neoplasm with an indolent clinical course and favorable outcomes with modern therapy. However, population-level disparities in survival remain incompletely defined. We evaluated the association of sex, race/ethnicity, household income, and residential area with 5-year OS among patients with HCL in the United States.

Methods

We identified patients with HCL from the SEER database from 2000 to 2021 using the ICD-10 morphology code C91.4. The primary outcome was 5-year OS. Patients with missing or unknown race/ethnicity, household income, residential area, or survival data were excluded. Kaplan-Meier methods estimated 5-year survival, and differences between groups were assessed using the log-rank test. Cox proportional hazards regression was used for multivariable modeling. Survival analyses were censored at 5 years, with HRs reflecting 5-year OS.

Results

A total of 5494 patients were included, with 1579 observed events. The cohort included 4344 male patients and 1150 female patients. Male sex was not significantly associated with survival compared with female sex (HR, 0.92; 95% CI, 0.82–1.00; P=0.157). Race/ethnicity included Hispanic patients (n=523), non-Hispanic White patients (n=4581), non-Hispanic Black patients (n=195), non-Hispanic Asian or Pacific Islander patients (n=180), and non-Hispanic American Indian/Alaska Native patients (n=15). Compared with Hispanic patients, survival was not significantly different among non-Hispanic White (HR, 1.1; 95% CI, 0.88–1.3; P=0.548), non-Hispanic Black (HR, 1.3; 95% CI, 0.95–1.7; P=0.099), non-Hispanic Asian or Pacific Islander (HR, 1.0; 95% CI, 0.72–1.4; P=0.924), or non-Hispanic American Indian/Alaska Native (HR, 1.5; 95% CI, 0.59–3.6; P=0.412) patients. By contrast, patients with a household income less than $70000 had inferior survival compared with those with an income of $70000 or more (HR, 1.3; 95% CI, 1.1–1.4; P<0.001). Rural residence was also associated with worse survival compared with urban residence (HR, 1.2; 95% CI, 1.1–1.3; P=0.004).

Conclusions

In this SEER-based analysis, lower household income and rural residence were associated with inferior 5-year OS in HCL, while sex and race/ethnicity were not significant predictors. These findings suggest that socioeconomic and geographic barriers may influence outcomes even in this highly treatable rare leukemia.