Infections in Hospitalised Patients with Multiple Myeloma: Main Characteristics and Risk Factors

Multiple myeloma is a common haematological malignancy and immune dysfunction is the hallmark of the disease. It leads to an increased infection risk, which is still a major cause of mortality. The infection spectrum and characteristics have evolved with the introduction of novel agents. An understanding of risk factors that increase susceptibility to infections is critical in fighting them. This retrospective investigation aimed to establish the incidence and main characteristics of infections in non-transplanted hospitalised myeloma patients in our department over a 3-year period, as well as factors associated with infections.

A total of 240 hospitalised patients with multiple myeloma (120 males and 120 females; average age: 69 years, range: 41-89 years) who were diagnosed or treated in our department from January 2008 to December 2010 were included in this study and their data were retrospectively analysed.

Infections were identified in 17.9% of hospitalised patients. The most common pathogen found was Pseudomonas aeruginosa. The frequency of gram-positive and gram-negative pathogens was similar. In 37.2% of cases, the agent was not isolated. The most common sites of infections were the urinary system and the blood (septicemia). The frequency of infection increased with duration of disease and the rate of reinfection was 41.9%. The patients treated with bortezomib had the highest infection occurrence. Fatal outcome occurred in 9.3% of cases.

The factors associated with infections in this investigation were female sex, 3B clinical stage of disease, increased serum creatinine and ferritin levels, neutropenia, poor general condition, and presence of catheters. Myeloma patients with one or more of these mentioned risk factors should be monitored with particular care in order to decrease the incidence and severity of infective complications.