Epidemiology and risk factors for the development of infectious complications in newly diagnosed multiple myeloma: a multicenter prospective cohort study in Uruguay.

Introduction: Infections represent a significant cause of morbidity and mortality in patients with multiple myeloma (MM). In Latin America, data on infectious complications in newly diagnosed MM (NDMM) patients are limited.

Methods: We conducted a multicenter, prospective cohort study of patients with NDMM in Uruguay between June 2019 and December 2020. Patients with active disease, on active therapy and who provided written informed consent were included. Elegible patients were followed for 6 months from the time of diagnosis and before proceeding to autologous stem cell transplantation or until death, whichever occurred first. Our primary endpoint was the number of infectious events that required hospitalization for ≥ 24 h.

Main Results: Of 124 patients with NDMM, 54 (43.5 %) had infectious complications (74 infectious events), the majority (74.3 %) within the first 3 months from diagnosis. The most common sites of infection were urinary (39.2 %) and respiratory tracts (33.8 %). The microbial agent was identified in 60.8 % of patients with Gram-negative bacteria (71.4 %) as the most common pathogen. Viral and fungal infections were infrequent. In the multivariable analysis, the Eastern Cooperative Oncology Group (ECOG) performance status was ≥ 2 (odds ratio [OR], 2.16; 95 % confidence interval [95 %CI], 1.23 - 3.79; p = 0.008) and creatinine ≥ 2 mg/dl (OR, 2.33; 95 %CI, 1.33 - 4.07; p = 0.003) were independent factors associated with bacterial infections. At 6 months, 14 patients (11.3 %) had died, 50 % related to infectious complications.

Conclusion: Bacterial infections are a substantial cause of hospital admissions and early death in patients with NDMM. Antibiotic prophylaxis should be considered to reduce infectious complications in patients with MM.