Outcomes of pneumococcal disease in patients with B-cell malignancies: A retrospective cohort study.

e23110 Background: Streptococcus pneumoniae disproportionately affects adults with B-cell hematologic malignancies due to profound humoral immune dysfunction and B-cell–depleting therapies. Although ACIP recommends pneumococcal conjugate vaccination for all immunocompromised adults, guidance does not distinguish B-cell malignancies from other hematologic cancers. National data defining severe inpatient outcomes in this high-risk subgroup are limited. We evaluated outcomes of pneumococcal disease hospitalizations among adults with B-cell hematologic malignancies. Methods: We conducted a retrospective study of hospitalizations with a principal diagnosis of pneumococcal disease using in the HCUP all-payer database (2018–2021). The primary exposure was B-cell hematologic malignancy. Primary outcome was in-hospital mortality; key secondary outcomes were invasive mechanical ventilation (IMV), length of stay (LOS), and total hospital charges. Weighted multivariable logistic regression (odds ratios [OR], 95% confidence intervals [CI]) and linear regression (beta [B]) adjusted for demographics, payer, socioeconomic status, comorbidity burden, sepsis severity, and hospital factors were used to estimate effects. Results: Among an estimated 186,860 pneumococcal hospitalizations, B-cell hematologic malignancy was independently associated with higher odds of IMV (OR 1.87, 95% CI 1.73–2.02; p < 0.001) but not increased in-hospital mortality (OR 0.97, 95% CI 0.86–1.10; p = 0.629). B-cell malignancy was associated with longer LOS (B = 0.69 days; p < 0.001) and a marginal increase in cost (B = $4,729; p = 0.051). Acute illness severity dominated outcomes: ventilator use strongly predicted mortality (OR 8.18, 95% CI 7.80–8.57; p < 0.001), and sepsis/severe sepsis were major drivers of IMV and death (all p < 0.001). In secondary analyses, results were directionally consistent when expanding exposure to all hematologic malignancies (IMV OR 1.87; mortality OR 0.95). Conclusions: Adults with B-cell hematologic malignancies hospitalized for pneumococcal disease experienced significantly higher risk of invasive mechanical ventilation and longer hospital stays, without increased adjusted in-hospital mortality. These findings support prioritization and systematic delivery of pneumococcal conjugate vaccination strategies in B-cell malignancy populations to reduce severe respiratory morbidity and healthcare utilization. Adjusted association of B-Cell hematologic malignancy with inpatient outcomes. Outcome Adjusted Effect Estimate 95% CI p-value In-hospital mortality OR 0.97 0.86–1.10 0.629 Invasive mechanical ventilation OR 1.87 1.73–2.02 <0.001 Length of stay (days) B = +0.69 0.43–0.96 <0.001 Total hospital charges (USD) B = +4,729 −29 to 9,487 0.051